At the conclusion of this brilliant exhibition, Dr. P.T. Austen made some remarks on

LABORATORY MANIPULATIONS.

The points referred to were the apparently unimportant details which often contribute so much to the ease and pleasure of working. First, the use of square pieces of felt, such as are used under beer glasses in saloons, for setting hot beakers and flasks on to prevent chilling and consequent cracking. Second, in crystallizing substances for examination under the microscope; one watch glass is placed upon another with the substance between them, and the upper glass filled with ether, the cold produced by its evaporation hastening the crystallization. Third, removing precipitates and solid matter from flasks, by heating to boiling, and inverting in a vessel of water. Fourth, crystallization by gradual dilution. Fifth, filter paper without ash. In German laboratories it is customary to dissolve out the mineral matter from white filtering paper by washing in dilute hydrochloric and hydrofluoric acids. Sixth, the use of infusorial silica for drying purposes. Being very porous, it will absorb five times its own volume of water. If a filter paper, holding a wet precipitate, be placed upon a layer of this earth, it will become quite dry in a very short space of time. Mr. Austen also remarked that substances retain their heat for several days when placed in cork boxes. To keep a substance air-tight, it may be placed in a flask, the neck painted with a solution of india rubber in chloroform, and a plate of glass laid upon it. The solvent quickly evaporates, leaving a delicate film of rubber, which holds the glass tightly in place.

The next meeting of the Chemical Section will be held February 12; of the Mineralogical Section, February 19.

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ANNUAL REPORT OF THE PATENT OFFICE.

The annual report to Congress of the Commissioner of Patents, for the year 1876, has made its appearance.

The amount received on applications for patents, reissues, designs, extensions, caveats, disclaimers, appeals, trade marks, labels, copies, etc., was $757,987.65. The amount paid for salaries was $425,930; other expenses, $226,612. Total payments, $652,542.

Number of applications for patents during the year 1876 21,425 Number of patents issued, including reissues and designs 15,595 Number of applications for extension of patents 2 Number of patents extended 3 Number of caveats filed during the year 2,697 Number of patents expired during the year 814 Number of patents allowed but not issued for want of final fee 3,353 Number of applications for registering of trade marks 1,081 Number of trade marks registered 959 Number of applications for registering of labels 650 Number of labels registered 402

Of the patents granted there were to—

Citizens of the United States 16,239 Subjects of Great Britain 511 Subjects of France 104 Subjects of other foreign governments 172 ——- Total 17,026

The number of applications for patents was a little less than during the previous year. The Commissioner suggests that Congress should appropriate $50,000 to promote the printing of the old patents; that additional examiners be employed, and more clerks, for the purpose of expediting the business of the office; that the price of the Official Gazette be reduced, also the fee for trade mark registration; that the library fund be increased; that more space be provided for models, and for the transaction of business.

In respect to the Centennial, the value of new improvements, and the service of the Patent Office in stimulating discovery, the Acting Commissioner speaks as follows:

"The display made at the Exposition by the Patent Office was creditable in every respect, and excited general attention. About 5,000 models of inventions, representing the leading branches of the arts and manufactures, were exhibited in suitable cases, and properly labeled, the various publications of the Office were displayed, its practice fully explained to all inquirers, and copies of the Patent Laws and the Office regulations and forms freely distributed. The knowledge of our patent system thus imparted to foreigners and all others unable to visit Washington has more than repaid the small cost attendant upon the representation. The exhibits were sent from and returned to the Office with scarcely any damage being suffered.

"But the array of models, etc., made by the Patent Office at the Exposition was not needed to illustrate the value of our patent practice. The wisdom of that system was demonstrated in the most practical and triumphant manner in nearly every branch of that munificent enterprise. Not only in the grand display of labor-saving machinery, but in the vast collection of manufactured articles, and even in the department of fine arts, were seen the fruits of that provision in our Constitution giving to Congress the power 'to promote the progress of science and the useful arts by securing for limited times to authors and inventors the exclusive right to their respective writings and discoveries.'

"Whatever persons may do in a 'perfect condition of society' in sharing, without price, the fruits of their labors with others, it must be apparent to the dullest observer that the wonderful growth of the useful arts in this country is due, thus far, to the protection given by our Government to property in inventions—a property as sacred as any other class of property, and whose value is determined by the same general law of supply and demand.

"It may be safely said that two thirds of the manufacturing interests of the country are based upon patents, and the welfare of all such interests are intimately connected with the welfare of the patent system. During the past seven years a larger number of applications for patents were filed and patents granted than during the entire seventy-eight preceding years, reaching back to the enactment of the first patent law. The needs of the Office have advanced in proportion to this sudden and vast increase of work, but have been but partly supplied. Nay, in fact, its already scanty force and accommodations have been actually reduced at a time when most required. If these vast interests, and the future promotion of science and the useful arts are to be encouraged, a liberal recognition must be made of the wants of this Office.

"The Examining Corps, the duties in which are most arduous and exacting, comprises gentlemen of legal, as well as scientific, attainments. It should be re-inforced by more of the same character. They should be relieved, by legislation, of continual embarrassment by reason of meager salaries and fears of removal incident to merely political changes. The Office would then be spared the continual loss of its most experienced and efficient men."

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THE IRON TRADE IN ENGLAND.

The British Mercantile Gazette of January 15 states that the situation and prospects of the iron trade have not materially improved in the month of December, but some week or two must elapse yet before trade returns to its regular channels. In the north of England the tone of the market is tolerably cheerful, and prospects, though still vague, are considered encouraging. Makers of pig iron go into the next quarter with a good supply of orders on their books, and merchants and consumers are desirous of buying over the first half of the year. Notwithstanding the great depression which has ruled throughout 1876, there is likely to be a greater production of pig iron by several thousand tons than ever there was before, and the total make must considerably exceed two million tons, which is twice the quantity turned out in Scotland, though in the latter district a greater number of furnaces have been kept in blast. Prices are nominally the same as were quoted last week, but show an upward tendency. The bulk of the mills and forges, foundries, etc., have resumed work, and the finished iron trade is again in full swing. The plate department is well provided with orders, but the rail manufacturers, though rather better off than they were, are still in a poor position. The miscellaneous branches of the iron trade, such as the foundries and tube, wire, and cut-nail manufactories are generally well off for orders, and engineers find plenty to do. The wages agreement in the finished iron trade ends this week, but it is thought that no alteration will be made. In the South Staffordshire iron trade, work has been only partially resumed as yet, and many of the mills and forges will not be started until the quarterly meetings, next week. Orders have rarely been so scarce as they are at this moment, arrears having been pretty generally cleared off before the holidays, and no new ones coming in. Nevertheless, the feeling of the trade is more hopeful than it was a month ago. The number of furnaces in blast in this district is now only 58 out of 153; but should the expected improvement in trade arrive with the quarterly meeting, this number will soon be increased. In the finished iron branch, in which quotations for marked iron contain the basis of $45 for bars, makers of leading brands of sheets and bars are better off than the manufacturers of cheap iron, who suffer much from competition in the north. Some considerable contracts for girders, bridges, gasometers, etc., are under execution at the works devoted to constructive ironwork; but the merchant iron trade, as a whole, is very dull. Unmarked iron is weak and variable, and to this circumstance may be attributed the reduction, announced this week, in various descriptions of common iron hardware.

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IMPROVED LATHE CHUCK.

The annexed engravings represent a new lathe chuck, which may be constructed of any size, which holds tools with great firmness, and which is provided with an improved device for taking up wear and for the separate adjustment of the jaws. The implement is made of the best steel, by special machinery, so that its parts are interchangeable.



Figs. 1 and 2 represent the chuck taken apart so as to exhibit the interior. Figs. 3 and 4 are sectional views. A is a collar which encircles the spindle, and has formed on its outer face a bevel gear wheel, B. C, Fig. 3, is the rear portion of the shell of the chuck inclosing the forward part of the collar, A. Also on said collar, A, is a washer, D, which rests against the shell, C, and a nut, E, which travels on a thread formed on the collar. As it is necessary, as will be explained further on, to turn the entire shell in order to move the jaws, the use of the nut just described is to jam the part, C, and the enlarged portion of the collar, A, tightly together, and so rigidly hold the jaws in any position in which they may be adjusted. Fig. 1 represents the outer face of the chuck with the jaws and their working mechanism. Within the chuck, each jaw has attached to it a screw, E. This enters a bevel wheel, F. As the jaws are incapable of any but radial motion, it follows that, when the chuck is rotated bodily and the bevel wheels engage on the motionless gear wheel, B, the effect of the rotation of said bevel wheels is to cause the jaws to travel toward or from the center of the chuck face. And it will be further clear that this motion must be simultaneous in all the jaws. As the outer portion of the chuck is rigidly secured to the shell, C, by screws, of course when that shell is jammed, as already stated, by the nut, E, it becomes impossible to turn the chuck bodily; and hence the bevel wheels cannot be rotated around the main gear wheel, and consequently the position of the jaws cannot be altered. The above comprises the mechanism proper of the device, that is to say, all that is necessary for moving or clamping the jaws.

There is, however, another feature of considerable importance yet to be described, and that is the device for taking up any play of the jaws due to wear, and which enables each to be adjusted so that the motion of all may be uniform. By referring to Fig. 4, it will be seen that, above the bevel wheel, there is a projection, into the threaded interior of which, as already explained, the jaw screw enters. Surrounding this projection is a sleeve, G, the outer surface of which is threaded to fit a similarly threaded aperture, cut partly in the shell and partly in the face plate. The upper portion of the sleeve is notched to receive a wrench or driver; and beneath the sleeve an armed washer, H, is slipped over the projection. The arms of this washer enter recesses in the face plate. It will be evident that, by turning the sleeve, F, so that the screw works inward, the jaw and all its appendages will be moved bodily in corresponding direction. But its movement is limited by the arms of the washer, G, which, through the narrowness of the recesses, are allowed only just enough play to compensate for slight changes in the jaw. As the above device is applied to every jaw, it follows that any one of them may be nicely adjusted from the outside, so that all are caused to grasp the tool accurately. The spindle, instead of being solid as represented, may be made hollow. Patented to J.H. Vinton, August 18, 1874. For further information, address the manufacturer, Mr. F. Armstrong, Bridgeport, Conn.

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SCREW-CUTTING LATHES.



An English lathe, now in use at the Rogers Locomotive Works, Paterson, N.J., contains several novel features. The ways are flat on the faces, instead of having raised Vs; and this is a feature of all English lathes, and of those known in this country as the Freeland lathes. A great deal of discussion has at various times taken place as to the relative qualification or merits of these two forms of lathe bed. The advocates of the flat way, with Vs at the edges of the way, claim superiority on the score of steadiness, increased wearing surface, and strength; while, on behalf of the raised Vs, it is urged that, the Vs being true, the saddle is bound to travel true, because there can be no lost motion on the slides; whereas any lost motion, from want of adjustment of the slides in flat ways, is liable to be reproduced twofold in the work, for the reason that 1/100 of an inch lateral movement of the slide carriage becomes 1/50 of an inch in the diameter of the work. Then, again, the most of the wear upon a lathe bed takes place at the part at and near the running center of the lathe, because the saddle is, on account of short jobs, more used in that part than on any other. As a result, when wear has taken place, the saddle, if adjusted to suit the worn part, becomes too tight to travel over the unworn part of the bed; and hence, after the wear has taken place, a proper adjustment of the lathe saddle becomes impossible if the job is a long one. In the case of raised Vs, however, the wear simply causes the saddle to fall vertically, so that an amount of wear equal to 1/100 of an inch would have the same effect as lowering the tool 1/100 inch, its effect upon the work being almost imperceptible by ordinary measurement. On the other hand, however, V lathes are usually made with either a weight or a spring to keep the saddle down; and as a result, when the cutting tool stands far out from the tool post, the saddle is apt to tip, especially in the case of boring with a lathe tool. In some cases, the raised Vs are accompanied with gibs to secure the saddle; but in many instances the gibs are given too little wearing surface. In the lathe above referred to, there are three ways in one casting, with the slide angles on the outer edges. There are also three separate and independent tail stocks fitting into the two openings between the ways. The running head has one cone pulley connected by suitable gearing to three face plates. The three centers at the running head are stationary. The slide rest saddle spans the three ways, having a V slide which contains three separate slide rests, all connected by a nut to the feed screw, so that all three are operated by the one screw. In addition to this, the two back slide rests have the nuts so attached that they can be moved by means of a separate screw, the object being to facilitate setting the cuts, since it would be a tedious matter to set all three tools to an equal cut, or to their desired respective cuts, without means of operating two of them independently. To set the cut during screw-cutting operations, the ingenious device shown in our engraving is provided. A represents the cross-feed or slide rest screw, which operates the three slide rests. It is fast to the notched wheel, B, and is operated by it in the usual way. C is a short screw which provides journal bearing for the screw, A, by a plain hole. It is screwed on the outside, and the plate in which it fits acts as its nut. It is fast to the handle, D, and is in fact operated by it. The handle or lever is provided with a catch, E, pivoted in the enclosed box, F, which also contains a means of detaining the catch in the notches of the wheel, or of holding it free from the same when it is placed clear. If, then, the lever, D, be moved back and forth the feed screw, A, and hence the three slide rests, will be operated; while, if the catch be placed in one of the notches on the wheel, B, both the screws, A and C, will act to operate the rests. When, therefore, the operator is cutting screws, he sets the catch, E, into one of the notches so soon as the tools are properly adjusted to the work; and then lifting the catch, E, he turns the wheel, B, so that the catch falls into the next notch, and this puts the cut on. When the tool has taken that cut, and while the latter saddle is traveling back, the catch is placed in the next notch, and so on, the cut for the forward travel always being put on as above while the saddle is traveling back. Thus is insured an exactly equable amount of cut on the whole three rests. When the lever, D, is not in use, the catch is removed from the wheel, B, and is allowed to rest against the pins, G or A, provided for that purpose. For piston rods, or for work such as cutting jack screws, this lathe is very useful. It is obviously, however, a special tool.

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NATURAL ORNAMENTS IN WINTER.

Now that the hedges are no longer green, and the trees stand black and bare on the landscape, is the time to seek for endless variety and beauty waiting to be admired in its turn. What miniature fairy glens and grottoes are distributed over the hedge banks of our country lanes! Mosses, delicate and beautiful, may be found in the interstices of any old wall, or at the foot of almost any tree or shrub. In the winter time mosses and lichens are found in fruit, and are beautiful objects. A pocket microscope lens is essential for their proper observation; and though the delicate carmine cups of the species known as the cup moss, and the familiar gray and yellow mosaic appearance we see on twigs and branches on our way, are easily recognized, the study of this form of winter vegetation is an inexhaustible one, and is an occupation for a lifetime, if earnestly pursued. We do not however, suggest that every one who endeavors to recognize the different species of moss, lichens, or fungi should necessarily do so through the medium of the microscope; but it will greatly add to the pleasure of making a collection out of doors if there be a good microscope at home, so that when the contents of the basket be turned out, after the winter's walk, there should be interest even in the fragments left, after a little pile of varied bits has been constructed, rivalling the choicest summer bouquet in beauty of form and color. We have seen such a collection formed into a beautiful object by raising a little mound of rough bits of bark in a plate or saucer, and placing on it varieties of fungus of every shade of red, brown, yellow, and gray. They seem to spring forth from a bed of sphagnum or bog moss of brightest emerald green; while a clump of the screw wall moss in fruit, with its curious little box-like capsules, supports a gray or yellow lichen, which has been gently removed from some old wall or tree. A bit of stick or a twig, incrusted with a bright orange-colored lichen, supports a trailing branch of delicate green ivy, the most beautiful and adaptable of all winter foliage. Over this little arrangement is placed a bell glass, to preserve it from dust and the effect of a dry atmosphere; and we know how pleasing to the eye is its varied beauty of form and color, lasting thus, a constant source of pleasure, for many a day without renewal.—Chambers' Journal.

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IMPROVED HARNESS COCKEYE.

We illustrate herewith a very simple little device for attaching traces to the single tree. It forms a secure fastening which may be instantly attached, and which, by its construction, is prevented from wearing out rapidly.



Fig. 1 shows the cockeye attached to the single tree, and Fig. 2 exhibits parts in section, displaying the construction very clearly. The yoke is of the usual pattern. Swiveled to it is a long loop, which is chambered out to receive a spiral spring which acts upon a plunger. The latter is provided with a follower having a semicircular notch, which corresponds in form to the inside of the end of the loop. The follower also has guiding lips which extend over the sides of the loop. Through the yielding of the spring, the space between the follower and loop adjusts itself to studs or hooks of any size. Patented December 12, 1876, through the Scientific American Patent Agency. For further particulars, address the inventors, Messrs. F.W. Knapp and C. Schallhorn, Fiddletown, Amador county, Cal.

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PROPOSED CREMATION TEMPLE.

Cremation, in this country at least, is not popular. For a time, it occupied here some public attention, but only in a sensational way; and the sober discussion of the subject, which followed after its novelty had worn off, led to the general opinion that, while every one might be quite willing to see his dead neighbors cremated, no one would acquiesce in the disposal of his friends and relatives in so abnormal a manner. Hence, with the single exception of the late revolting exhibition in Pennsylvania, which we alluded to at the time, the dead in this country have continued to be deposited in their hallowed resting places, and have not been packed away, in an incinerated state, in labeled urns. In Europe, however, cremation still finds many warm adherents; and during last summer a congress of the "Friends of Cremation" (a society which, we are informed by Engineering, whence we take the annexed engravings, has branches in various parts of the world), was held in Dresden. Before this meeting, a large number of designs for cremation and mortuary buildings were brought in competition, and finally the prize was awarded to Mr. G. Lilienthal, a Berlin architect, for the imposing structure illustrated herewith.

This will be the grand temple of cremation when it is erected—a proceeding to take place in the dim future: when or where not stated. On each side of a central chapel there is a circular memorial hall; and extending so as to inclose the garden of the establishment, on the sides of the halls are wings containing a large number of niches for the reception of funeral urns.

The cremation ceremony is proposed to be as follows: The body, having been brought into the hall, is subjected to the usual medical examination; or when an inquest is necessary, it is removed to offices in another part of the building, where the required investigation can be held. When all is ready, the body, placed on the platform, B, Fig. 2, is raised by a lift into the hall, A, where visitors are gathered, and here the result of the medical examination is declared, and whatever preliminary religious ceremonies that are desired are performed. The body is then transported to the chapel, E, in front of the pulpit, F, where the burial service is performed. The bier is afterward lowered mechanically, and brought to the furnaces, which are arranged in a semicircle and partitioned for the reception of several biers. The ashes are subsequently placed in an urn, on which the name, etc., of the deceased are recorded, and which is set up in a suitable niche.



The building, which we illustrate both in elevation, Fig. 1, and in plan, Fig. 2, is designed to contain 100,000 urns, and is adapted for a town of 200,000 inhabitants. The architect has certainly exhibited much taste in his design for the building, and has provided every convenience in the internal arrangement for carrying on a large business in the cremation line.



* * * * *

HOW TO REJUVENATE AN OLD ROSE BUSH.

Never give up a decaying rose bush till you have tried watering it two or three times a week with soot tea. Make the concoction with boiling water, from soot taken from the chimney or stove in which wood is burned. When cold, water the bush with it. When it is used up, pour boiling hot water on the soot a second time. Rose bushes treated in this way will often send out thrifty shoots, the leaves will become large and thick, the blossoms will greatly improve in size and be more richly tinted than before.—D.H. Jacques.

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A CLOCK COLLECTOR.

One of those odd geniuses, who spend their lives and means in collecting curious and rare articles, lately died. His name was Sylvester Bonaffon, a retired merchant of Philadelphia. His elaborate collections were sold at auction, and their oddity has attracted general attention. His chief mania was for clocks, which literally covered every portion of available space in his apartments, whether they were placed on chairs, tables, shelves, or hung against the wall. Some of these timepieces were of unique construction. One clock was made to run for 400 days after one winding; another was set in the dashboard of his carriage, and he used Mr. Bonaffon also had an especial fondness for electrical apparatus. His windows were provided with ingenious burglar alarms, his rooms with fire alarms, and he ignited his gas always by electricity. His place of business, his stable, the Continental Hotel where he dined, were all connected with instruments in his room; and he even had perfected arrangements so that he could set at home and send his own messages to California. Besides the clocks and electric apparatus, there was an immense collection of bric-a-brac of every conceivable variety, which was sold at the auction—as is usually the case—at prices much below those paid by its late owner.

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FERTILIZING INFLUENCE OF SNOW.

Snow is often called the "poor man's manure;" and if it is true that it has any manurial value, the farmer's prospects for the next season are certainly flattering. The body of snow upon the ground in all the Northern and Middle States is very great, and millions of acres of land are covered by it as with a blanket of the whitest wool. It is probable that seldom, perhaps never, has so wide an area of our country been covered as during this month of January, 1877. The question whether snow is capable of affording to lands any of the elements of fertility is one often asked; and in reply, the Boston Journal of Chemistry says that it probably is. The atmosphere holds ammonia and some other nitrogenous products, which are without doubt brought to the soil by snowflakes as well as by rain drops. Experiments both here and abroad would seem to prove the truth of this conclusion.

Rains are not only valuable for the moisture which they supply, but for what they bring to us from the atmosphere. During a thunderstorm nitric acid is produced in considerable quantities; and dissolved in the rain drops to a high degree of attenuation, its effects upon soils are highly salutary, as the nitrogen permeates the entire soil.

* * * * *

ACTION OF SEA WATER ON LEAD.

The Journal of the Chemical Society says that freshly cut strips of lead were kept in a bottle of sea water for four days, the bottle being frequently shaken. No trace of lead could be detected in the water, but the bright surface of the strips was coated with an insoluble lead compound. Hence lead pipes may be used in marine aquaria without any fear of injury to their inhabitants.

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PAPIN'S STEAM ENGINE.

BY PROFESSOR CHARLES A. JOY.

It is a matter of history that, as early as 1688, Denis Papin, Professor of Physics and Mathematics at the University of Marburg, proposed to substitute steam for powder in the engine invented by Huyghens, and that in 1695 he published a description of several new inventions, in which steam played an important part. The Elector Carl, of Hesse-Cassel, was anxious to be free from the annoyances and impositions practised upon his boatmen by the authorities at Muenden, and he proposed to avoid that city by constructing a canal connecting the Weser with the river that flowed through Cassel. Much of the work was accomplished, and the half finished line of the canal can be traced even at the present day. Papin was authorized to build a powerful steam pump by which the supply of water was to be regulated. A working model of this pump was completed; and the Elector was on the point of visiting the laboratory to witness its operation, when a fearful explosion frightened the workmen, and afforded an opportunity for enemies to intrigue for the expulsion of Papin from the country. The model was preserved for a long time in Cassel; but at the time of the French invasion, it disappeared, and no trace of it has since been found. In writing about his inventions, Papin says, in 1695: "It would occupy too much space for me to describe in what manner this principle could be applied to removing water from mines, throwing bombs, sailing against the wind, and for many other similar purposes; everyone according to his wants can imagine the constructions that could be made. I cannot, however, refrain from remarking how much preferable this power would be to oars for those whose business calls them to the sea." And further on he says: "The steam cylinders could be employed for a great variety of purposes." One of the cylinders, which was to form a part of the pump, was cast at the foundry in Cassel, and after various vicissitudes has finally become the property of the Historical Museum in that city, where it will be preserved, with jealous care, from any further injury. During the recent exhibition of philosophical instruments in London, this remnant of Papin's invention played an important part, it having been generously loaned by the authorities for that occasion. After the flight of Papin from Germany, the cylinder was used as a receptacle for iron turnings and borings in the royal works; and after the destruction of those works by fire, it came into the possession of Henschel, the founder of one of the most extensive locomotive works in Germany. This man fully appreciated the value of the historical relic; and when I visited him at the works, twenty-five years ago, he pointed out with pride to me the inscription on its side, "Papin's Cylinder," and said that he intended to have it placed upon a solid pedestal near the gate. His grandson has since presented it to the city, and its preservation from destruction or sale is now secured. A copy of the drawing made by Papin of the pump of which this cylinder was to form a part, and which was published in 1695, has recently appeared in Dingler's Journal, and I send it to you, hoping that you will have it engraved and perpetuated in your valuable paper. It is a peculiar combination of Savery's invention and Papin's piston engine, suggested for another purpose, and is a decided improvement on Huyghens' powder engine.



A is the boiler for the generation of the steam, provided with a safety valve (an invention of Papin). On opening the stopcock, C, the steam passes through B into the cylinder, D, and by its expansion drives the plunger, E, against the water contained in the cylinder, D, which is thus forced into the chamber, F, compressing strongly the air, which in turn expels the water through the pipe, G, to the height desired. K is a funnel for the fresh supply of water, and at I and H are valves opening upwards and downwards. After the condensation of the steam in D, a renewed supply of water, through K, forces the plunger, E, to the top of the cylinder, ready for the next action of steam. The strokes of such a pump could not be frequent, and it would not compare very favorably with the wonderful machinery exhibited in Philadelphia last summer; but it contains the germ of the idea, and is worthy of all honor. Having often seen it stated that Papin had invented a steamboat, I resolved during a recent visit to Germany to investigate the matter, and especially to search for the correspondence between Papin and Leibnitz in the library at Hanover. It will be borne in mind that two hundred years ago, on December 4, 1676, Leibnitz was appointed to take charge of the library in Hanover, and that he remained in this position until his death in 1716. He bequeathed his manuscripts to the library; and as he had the habit of writing upon all manner of loose scraps of paper, it has cost much labor to assort and classify them.

On making my application to the librarian to be permitted to see the correspondence between Papin and Leibnitz, my request was at once granted; and a table having been assigned me, I was able to examine these precious relics at my leisure. I was also shown a copy of an original treatise on the steam engine by Papin, which contained numerous marginal notes by Leibnitz. In one place, Leibnitz criticized Papin's method for condensing steam, and makes a drawing on the margin, showing a piston and valve which he thought would be more practical. It is somewhat remarkable that the Germans have not caused a fac-simile of this little volume to be published. After considerable search, I found a copy of the original letter addressed by Papin to Leibnitz in 1707, asking Leibnitz to assist him in obtaining the consent of the Hanoverian Government to navigate the river Weser with a sidewheel steamboat. The letter was dated July 7, 1707, and contained among other interesting passages the following sentence: "The new invention will enable one or two men to accomplish more effect than several hundred oarsmen." It is evident that Leibnitz was deeply impressed by Papin's letter, and he supported the simple and reasonable request contained in it by the following petition addressed to the Councillors of State. This communication from Leibnitz bears two indorsements, one by the clerk of the council, "pro memoria respectfully, in reference to the passage of a ship from the river Fulda into the Weser;" the other is in the handwriting of Leibnitz: "Papin's sidewheel ship." This last indorsement is of great value, as indicating the fact that Papin proposed to apply side wheels for the propulsion of his new invention. The following is a translation of Leibnitz' letter, the original of which I saw in the library:

"Dionysius Papin, Councillor and Physician to his royal highness the Elector of Cassel, also Professor of Mathematics at Marburg, is about to dispatch a vessel of singular construction down the river Weser to Bremen. As he learns that all ships coming from Cassel, or any point on the Fulda, are not permitted to enter the Weser, but are required to unload at Muenden, and as he anticipates some difficulty, although those vessels have a different object, his own not being intended for freight, he begs most humbly that a gracious order be granted that his ship may be allowed to pass unmolested through the electoral domain, which petition I most humbly support.

G.W. LEIBNITZ. "Hanover, July 13, 1707."

This letter was returned to Leibnitz with the following indorsement: "The Electoral Councillors have found serious obstacles in the way of granting the above petition, and, without giving their reasons, have directed me to inform you of their decision, and that in consequence the request is not granted by his Electoral Highness.

H. REICHE. "Hanover, July 25, 1707."

This failure of Papin's petition was the deathblow to his effort to establish steam navigation. A mob of boatmen, who thought they saw in the embryo ship the ruin of their business, attacked the vessel at night and utterly destroyed it. Papin narrowly escaped with his life, and fled to England, where he endured great hardships and poverty, and all traces of him were soon lost, so that it is uncertain in what country he finally died or where he was buried.

This remarkable man was driven out of France on account of his Protestant faith, and found a refuge in Germany; here he was again persecuted on account of the injury that ignorant and jealous people believed his inventions would inflict upon the industries of the country; and when the climax of steam engines for pumping water and propelling ships was reached, the enlightened government of the period "found serious obstacles" in the way of granting him protection, and, without condescending to state what those "objections" were, secretly instigated the mob to make an end of the trouble. It is another instance, unfortunately too often repeated in history, of the mischief men dressed up in a little brief authority can work upon their generation. If Papin had been permitted to navigate the Weser with his ship, and to carry it to London, as was his intention, it is possible that we should have had steamboats one hundred years earlier than they were given to us by Fulton. The plan proposed by Papin was highly impracticable; but a knowledge of what Savery had done in the way of steam machinery, aided by the shrewd suggestions of Leibnitz, combined with the practical assistance of Englishmen, would, no doubt, have enabled him to improve upon his invention until it had obtained sufficient credit to be secure against the misfortune of being totally forgotten. After the lapse of 100 years from the date of Papin's invention, when the first steamboat was put upon the river Rhine, the vessel was fired into by concealed marksmen on shore, and navigation was more dangerous than it is now on the upper waters of the Missouri in times of Indian hostility. It was only after stationing troops along the banks of the river to protect the boatmen that the government, fortunately more enlightened than in the days of Leibnitz, was able to establish steam navigation on a secure footing.

I have thought it worth while to make this contribution to the history of steam navigation, particularly as I have been able to authenticate a portion of it by reference to original documents.

Columbia College, New York city, January, 1877.

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THE SPEAKING TELEGRAPH.

We have heretofore given accounts of the wonderful success of Professor Bell in transmitting the vibrations of the human voice by electrical means over a telegraph wire. He has lately made improvements in his method of transmission, by which he dispenses with the use of the battery, and substitutes the magneto-electric plan of producing the current. The Boston Transcript describes a recent experiment with the new apparatus, by which conversation and singing was successfully carried on between Boston and Malden, a distance of six miles. The telephone, in its present form, consists of a powerful compound permanent magnet, to the poles of which are attached ordinary telegraph coils of insulated wire. In front of the poles, surrounded by these coils of wire, is placed a diaphragm of iron. A mouthpiece to converge the sound upon this diaphragm substantially completes the arrangement. As is well known, the motion of steel or iron in front of the poles of a magnet creates a current of electricity in coils surrounding the poles of the magnet, and the duration of this current of electricity coincides with the duration of the motion of the steel or iron moved or vibrated in the proximity of the magnet. When the human voice causes the diaphragm to vibrate, electrical undulations are induced in the coils environing the magnets, precisely analogous to the undulations of the air produced by that voice. These coils are connected with the line wire, which may be of any length, provided the insulation be good. The undulations which are induced in these coils travel through the line wire, and, passing through the coils of an instrument of precisely similar construction at the distant station, are again resolved into air undulations by the diaphragm of this instrument.

The experiments were as follows: Telephones having been connected with the private telegraphic line of the Boston Rubber Shoe Company, conversation was at once commenced. Stationed at the Boston end of the wire, Professor Bell requested Mr. Watson, who was at the Malden end, to speak in loud tones, with a view of enabling the entire company at once to distinguish the sounds.

This was so successful that a smile of mingled pleasure and surprise played on the features of those present. That it, however, might not be supposed that loud speaking was essential to intelligibility, Mr. Bell explained that soft tones could be heard across the wires even more distinctly than loud utterances, even a whisper being audible. In confirmation of this statement, Mr. Watson commenced speaking in turn with each member of the company; and after the efficiency of this method had been proved to the satisfaction of all, he took up a newspaper and informed the assemblage that gold had closed the previous evening at New York at 105-5/8. As there were quite a number of business men present, the effect that this practical demonstration of the value of the telephone produced can scarcely be exaggerated. Other passages from the daily journals were then given, and by this time the desire for conversation having become general, Mr. Watson was plied with questions such as: "Is it thawing or freezing at Malden? Who will be the next President?" etc. It was remarkable that Mr. Watson was able to distinguish between the voices at the Boston end, he calling at least one gentleman by name as soon as the latter commenced speaking.

This went on for some time, until a lady at the Malden end sent the company an invitation to lunch per telephone, and an appropriate response was made by the same medium. At length the Boston company were requested to remain quiet while a lady at the other end conveyed to them the sweet strains of music. The assemblage thereupon listened with rapt attention while a young lady commenced singing "The Last Rose of Summer." The effect was simply charming. The sound of the voice penetrated into the Boston end of the telephone with a distinctness equal to that attainable in the more distant parts of a large concert room, and a unanimous vote of thanks was sent by the handy little instrument which had procured for the assemblage so agreeable an hour.

* * * * *

The superb steam engine built by C.H. Brown & Co., of Fitchburg, Mass., which was illustrated and described on page 1 of our current volume, has been purchased by Messrs. Phineas Jones & Co., and is being erected in their extensive carriage wheel works at Newark, N.J.

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CROSSING A RIVER ON A WIRE.

A reporter of the New York Sun wanted to realize the sensation of being suspended on a wire 275 feet from the surface of the earth. He applied to the engineer of the Brooklyn bridge for permission to cross the East river on a wire, three quarters of an inch in diameter, which hangs between the two towers. He was refused permission; but he finally saw the president of the company, who granted his request. Arriving at the appointed time, the engineer, Mr. Farrington, said: "Well, sir; whenever you're ready, I am."

"All ready, said I, as bold as brass outside, and as nervous as the Endorian witch on the inside. He walked on and I followed, when, Horror of Horrors—capital H's—to both Horrors—instead of leading me to the 'cradle,' which I called a raft, he took me to a little square board held up by two crossed iron arms, called a 'buggy.' It was about three feet square, and depended from the 'traveler,' a three quarter inch wire which crosses the river, and is run from tower to tower over apparatus, by means of a stationary engine. It was too late to back out, but I didn't feel exactly prepared to plunge in. He did.

"He jumped in, and the little buggy swung from side to side, precisely as a swing does when you jump on the board and try to steady it by the ropes. I looked at him, at the scale—that's it; it's exactly like a pair of scales, with one scale—at the deep depths below us, and at myself. I imagined the ticklish thrill which would permeate my body when we started. I fancied the glories of the prospective perspective before me.

"'Come, hurry up, please,' interrupted Farrington, and with resignation I hurried down. He stood up. I crouched down. Perhaps you think you'd have stood up as he did. You're mistaken. I crouched down and held on tight. Make no mistake. I held on tight and waited for my thrill. It didn't come. Then I stood up, and Farrington gave the word 'Go.' 'Wouldn't you better take a rope along?' said one of the men. 'Yes, I think I would.' What did he want of a rope? He feared I would be nervous. He meant to grapple me in the middle of the river, and tie me in. I knew it. I felt it. But I didn't say a word.

"With a gentle jerk we started—slow, slow, very slow. Farrington stood in front and watched the wire. I stood behind and watched myself. I felt nothing. I was'n't exhilarated. I was'n't scared. I was'n't even timid. I can't look from the top of a house without desiring to jump off, but I looked down from the buggy and hadn't the least desire to jump. Farrington says: 'It's because it's so high up.' Well, we went on without any special sensation till the buggy struck against a stay rope which reaches from one of the cables to the tower. In the effort to free the buggy, Mr. Farrington gave a push which swung us out some little distance and back again, at which a little piece of indigestion seemed to be monarch of my interior, and for a moment I was on the verge of a sensation. Having passed the middle, the ascent was more labored. I waved my handkerchief to the people on the ferryboats. I looked out toward the sea. I looked up at the heavens. I even looked toward Harlem, but, like the buyer in the Bible, I said: 'It is naught, it is naught.'

"In about eight minutes we touched the New York side—all but ten feet. The red flag waved for the engine to stop. There we hung in mid-air 275 feet above the level, swinging to and fro like a drunken buggy, at an angle of forty degrees, and quite uneasy. The rope which was to haul us on was fastened to the iron—blest be the tie that binds—and with a few hearty pulls we were brought so near the New York tower that without difficulty we clambered up. I had made the trip, but I had not felt a feel. From the top of the New York tower I saw much, but the chief point of interest was the innumerable jets of steam which flourish in the air, and fantastically curl off into space.

"Again the steeples, the tower, and the long, narrow, dirty river filled the prospect, and the bright sun of a charming day lightened up the western sky That was all, except to say 'thanks and good-bye,' and descend the stairs. There were 417 of them stairs, and before I reached the bottom I was dizzy, faint, seasick, and filled with a decoction of tickle, so that I had to shut my eyes and rest from my labors.

"Thus ends the trip which filled my anticipatory imagination as the waters fill the sea, but which resolved itself in realization to a simple, childlike faith in the fixtures on the wire, and in the skill and competence of the man who guided them. MONSIEUR X."

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BLUE GLASS SCIENCE.

There is nothing more reassuring in these days, when new "isms" of the scientists are slowly sapping the foundations of cherished beliefs, than to remember that, after all, the much vaunted dicta of Nature are yet opposable by the sound operations of honest common sense. See for example how one of our evening dailies, tossing the dogmas of so-called science contemptuously aside, evolves such profoundly original thoughts as these, to explain the lucid blue glass theory of General Pleasonton: "The blue glass presents an obstruction to the sun's rays which can only be penetrated by one of the seven primary rays—the blue ray; the remaining six rays, travelling with the velocity of 186,000 miles a second, falling upon the blue glass, are suddenly arrested; the impact evolves upon the surface of the glass friction, heat, electricity and magnetism; the heat expands the molecules of the glass, and a current of electricity and magnetism passes through it into the room; this current, falling upon animal or vegetable life within, stimulates it to unusual vigor. Certainly the results achieved, and abundantly certified to, are marvellous, and sufficient to provoke further experiments and inquiry." Prior to these splendid original discoveries of our contemporary, we ignorantly believed that blue glass only partially sifted out the orange and yellow rays from the spectrum, and that with this exception, it acted merely as a screen to diminish the intensity of all the rays. We also supposed that there was a sharp distinction to be drawn between sunlight after passing through blue glass and the blue spectral ray: that in one case all the colored rays were more or less present, and that in the other but one was. But think of the utter dismay of such pretenders as Helmholtz, Tyndall, and Henry when they learn that the undulatory theory of light with which they have so long taxed our credulity is overthrown—that of the seven primary rays, six bounce off from blue glass and distribute themselves over the adjoining neighborhood. That the glass is heated by the impact; and as the sun persistently emits more rays, there are more impacts and more heat. The glass gets hotter and hotter; but—mark the scientific acumen here—just as we are wondering whether it will reach the melting point, the pores open. It is the Turkish bath of Nature. Electricity and magnetism, no longer shut out, rush in between the separate molecules. Hand in hand, these great curative powers seek a proper subject. They meet (we learn from a report, also in our contemporary, of Pleasonton's latest triumph) a pig or a young lady whose hair has come out—a heifer, a rooster, or a rheumatic child. Forthwith the pig fattens, hair equal to that produced by the finest tricopherus pervades the female scalp, and "unusual vigor" and general happiness prevail. Such is the boon which Pleasonton bestows on humanity, as elucidated by the original genius of our contemporary.

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INFECTIOUS DISEASE PROPAGATION.

In view of the alarming prevalence of scarlet fever in many parts of the country, the following hints by the British Medical Journal are wholesome warnings: "There are three common ways by means of which infectious diseases may be very widely spread. It is a very usual practice for parents to take children suffering from scarlet fever, measles, etc., to a public dispensary, in order to obtain advice and medicines. It is little less than crime to expose, in the streets of a town and in the crowded waiting room of a dispensary, children afflicted with such complaints. Again, persons who are recovering from infectious disorders borrow books out of the lending departments of public libraries; these books, on their reissue to fresh borrowers, are sources of very great danger. In all libraries, notices should be posted up informing borrowers that no books will be lent out to persons who are suffering from diseases of an infectious character; and that any person so suffering will be prosecuted if he borrow during the time of his illness. Lastly, disease is spread by tract distributors. It is the habit for such well meaning people to call at a house where a person is ill and to leave him a tract. In a week or so the tract is called for again, another left in its place, and the old one is left with another person. It needs not much imagination to know with what result to health such a practice will lead if the first person be in scarlet fever or smallpox."

Dr. Hutton offers "a warning on the reckless manner in which parents allow their healthy children to run into the houses of acquaintances who have members of their families suffering from scarlatina, etc., and states that he has seen the infection thus carried from the patient, and several families attacked."

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TOUGHENED GLASS MAKING IN BROOKLYN.

A World reporter has lately visited the works in Brooklyn where the manufacture of the La Bastie toughened glass is now in active progress. The manufacturer states that, in June last, his factory was destroyed by fire, and the introduction of the glass into our markets has for that reason been delayed. Only one kind of goods, lamp chimneys, are now made, and the process is as follows: A workman, having in his hand a pole about eight feet long, with a knob on the end of the size of a lamp burner, fits a chimney on the knob and plunges it into the flame of a furnace. He with-draws it twice or thrice that it may not heat too quickly, turning the pole rapidly the while, and when the glass reaches a red heat quickly shoots it into one of a dozen small baths fixed on a revolving table, and seizes another chimney. A boy keeps the revolving table always in position, and as the chimneys come around to him, having been the proper time in the bath, he takes them out to be dried, sorted, cleaned, and packed. The bath has to be of just the right temperature, as, if it be too hot or too cold, the chimneys are liable to explode. In either case the process of annealing is imperfect. By working the tables at a certain rate, the baths are kept at the right temperature by the immersion of the red hot glass. Oil or tallow is used in the bath. Any greasy substance will do, though tallow has proved most satisfactory.

M. De la Chapelle, the manufacturer, states that he has already sold $150,000 worth of the chimneys. The toughened chimneys are about 60 per cent dearer than those of ordinary glass. The factory is in Delavan street, Brooklyn, N.Y.

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ALEXANDER BAIN, ELECTRICIAN.

This ingenious man, whose inventions in connection with the electric telegraph entitle his name to be held in grateful remembrance, died in January last at the new Home for Incurables at Broomhill, Kirkintilloch, near Glasgow, Scotland, and on Saturday his remains were interred in the burying ground in the neighborhood of that town known as the Old Aisle Cemetery. Mr. Bain, who was about sixty-six years of age, was a native of Thurso. He was the inventor of the electro-chemical printing telegraph, the electro-magnetic clock, and of perforated paper for automatic transmission of messages, and was author of a number of books and pamphlets relating to these subjects. Sir William Thomson, in his address to the Mathematical Section of the British Association at its meeting in Glasgow last year, said: "In the United States Telegraphic Department of the Great Exhibition at Philadelphia, I saw Edison's automatic telegraph delivering 1,015 words in 57 seconds. This was done by the long neglected electro-chemical method of Bain, long ago condemned in England to the helot work of recording from a relay, and turned adrift as needlessly delicate for that." Mr. Bain was stricken by paralysis, and suffered from complete loss of power in the lower limbs. For some time he had received a pension from the government, obtained for him, we believe, through the instrumentality of Sir William Thomson. Mr. Bain was a widower, and has left a son and daughter, the former of whom is in America, and the latter at present on the Continent. Photographs of him by Mayall were recently presented to the Society of Telegraph Engineers and the American Society of Telegraphers at Philadelphia. —The Engineer.

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SELF-RELIANCE NECESSARY TO SUCCESS.

Self-reliance, conjoined with promptitude in the execution of our undertakings, is indispensable to success. And yet multitudes live a life of vacillation and consequent failure, because they remain undetermined what to do, or, having decided that, have no confidence in themselves. Such persons need to be assured; but this assurance can be obtained in no other way than by their own successes in whatever they may attempt for themselves. If they lean upon others, they not only become dissatisfied with what they achieve, but the success of one achievement, in which they are entitled to but partial credit, is no guaranty to them that, unaided, they will not fail in their very next experiment.

For want of self-reliance and decision of character, thousands are submerged in their first essays to make the voyage of life. Disappointed and chagrined at this, they underestimate their own capacities, and thenceforward, relying on others, they take and keep a subordinate position, from which they rise, when they rise at all, with the utmost difficulty. When a young man attains his majority, it is better for him, as a general rule, to take some independent position of his own, even though the present remuneration be less than he would obtain in the service of others. When at work for himself, in a business which requires and demands foresight, economy, and industry, he will naturally develop the strong points of his character, and become self-reliant.

A glance at the business men of any community will show who have and who have not improved the opportunities of their earlier years. The former transact their business with ease, promptitude, and profit. They rely upon themselves, and execute what they have to do with energy and dispatch. But those who shirked everything in their youth are compelled to rely on their clerks and salesmen for advice, and are never ready to act when occasions of profit arise. Many parents commit a lamentable error in this respect. They lead their children to believe that they can do nothing without the constant assistance of their superiors, and after awhile the child becomes impressed with that idea. Fortunate will it be for him when he emerges from the parental roof, if he can at once acquire the self-reliance which has been kept down at home—otherwise he must necessarily fail in whatever independent enterprise he undertakes; and in such a case, while the misfortune is his own, the fault lies at the door of misjudging parents rather than at his own.

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SOMETHING TO DO.

It is an old trick of despots, and a good one, to employ their subjects. Why? To keep them out of mischief, Employed men are most contented. There is no conspiracy. Men do not sit down and coolly proceed to concoct iniquity so long as there is plenty of pleasant and profitable employment for body and mind. Work drives off discontent, provided there is compensation in proportion to the amount of labor performed. There must be a stimulant. God never intended a man should sweat without eating of the fruits of his labor—reaping a reward—more than he intended the idle man should revel in plenty and grow gouty on luxuries. Industry is a great peacemaker—a mind-your-own-business citizen. Something to do renders the despairing good-natured and hopeful—stops the cry of the hungry, and promotes all virtue. The best men are the most industrious; the most wealthy work the hardest. They always find something to do. Do you ever wonder that men of wealth do not "retire" and enjoy their substance? We know some young men look forward with anticipation to the time of "retiring." It is doubtful if a man should ever retire from business as long as he lives. We think we know men who, were they to abandon business, would be ruined, not pecuniarily, but mentally—their lives would be shortened. God never intended man's mind should become dormant. It is governed by fixed laws. Those laws are imperative in their exactions.

Something to do! "Oh, if I had something to do!" There are young men who sigh for it, yet one thing they can do—that is, seek for a job. Once found, provided it is an honest one, do not hesitate to perform it, even if it does not pay as well as you expected.

* * * * *

MONEYED MEN.

The Cleveland Herald said, twenty years ago, during a stringency of the times, that moneyed men are the veriest cravens on earth: so timid, that on the least alarm they pull their heads, turtle-like, within their shells, and, snugly housed, hug their glittering treasure until all fear is removed. The consequence is that a few days' disturbance of the monetary atmosphere brings on a perfect dearth of not only the precious metals, but even of paper money, their representative. Moneyed men never adopt the tactics of mutual support; hence, as soon as a shot is fired into the flock, they scatter, each looking out for himself, each distrustful of the other, and each recognizing only the great law of selfishness, which is to take care of number one. Courage has saved many an army, even when ammunition was low; and many a foe has been scattered by one yell of defiance when there was not a cartridge left.

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NEW BOOKS AND PUBLICATIONS.

ARCHOLOGY, OR THE SCIENCE OF GOVERNMENT. By S.V. Blakeslee. Price $1.25. New York and San Francisco: A. Roman & Co.

This book is a very metaphysical treatise on theories of government and the duties of citizens to the law, each other, and themselves. Theoretical politics are little in favor with thinking men of this day; and the social difficulties of our age will have to be solved by practical wisdom founded on experience. The people that knows that a certain course of legislation has destroyed an empire, and that a contrary policy has developed one, will care little as to whether or not "the will controls the feelings by mediate and indirect force." We are unable to find in this book any attempt to apply the finely worded theories stated to practical use and popular instruction in political science.

GRAPHICAL ANALYSIS OF ROOF TRUSSES, FOR THE USE OF ENGINEERS, ARCHITECTS, AND BUILDERS. By Charles E. Greene, A.M., Professor of Civil Engineering in the University of Michigan. Chicago, Ill: George H. Frost.

The author of this work truly says that any designer who fairly tries the graphical method will be pleased with the simplicity and directness of the analysis, even for apparently complex forms. The hindrance to the general use of the method is the want of knowledge of the higher mathematics, which are largely used in most treatises on the subject. Professor Greene has avoided this stumbling block, and given us a treatise which may be understood and appreciated by any one of common school education. We therefore give his work a hearty commendation, and we hope that every carpenter and builder may be induced to analyze the stresses which affect the different parts of structures, which he can readily do by carefully reading this volume.

THE HUB: a Journal devoted to the Carriage Building Trades. Published monthly. Subscription price, $3.00 a year. New York city: The Hub Publishing Company, 323 Pearl street.

This journal is widely known for its accurate and extended information as to carriage building, trimming, lining, painting, etc.; and since its first issue it has maintained its reputation, and given the public an immense amount of instruction in a spirited and practical manner. The illustrations and typography are excellent, and every number shows how extended an area it serves as an authority on the important industry to which it is devoted.

ASSIGNATS AND MANDATS: the Money and the Finances of the French Revolution of 1789. By Stephen D. Dillaye. Price, free by mail, 30 cents. Philadelphia, Pa.: Henry Carey Baird & Co., 810 Walnut street.

Mr. Dillaye differs with the Hon. A.D. White, President of Cornell University, as to the relative merits of money and promises to pay money; and he begins with the assertion that the President's "object is to depreciate American credit, stability, and honor." Further perusal, to ascertain the meaning of this attack on a patriotic and useful member of society, shows us what Mr. Dillaye thinks he means. He talks of credit being the vital element of national power; and from this he argues that the more "credit" a nation has—that is, the deeper it is in debt—the more powerful it becomes. In short, he confuses credit as opposed to discredit with credit as opposed to cash—a grievous blunder, surely. A nation's credit is like a merchant's; it becomes greater only as his debts become smaller; and people trust a government for the same reason as they trust an individual, mainly because every previous obligation has been honorably observed. It is gratifying to know that persons of Mr. Dillaye's way of thinking are few and unimportant, and their number is diminishing daily.

CROTON WATER SUPPLY FOR THE CITY OF NEW YORK: an Address by George B. Butler to the New York Municipal Society. New York city: Published by Order of the Society, 87 Madison avenue.

A review of the whole subject of our water supply, its sources and the area they drain, the geographical features of the district, and the works erected by the city. Mr. Butler maintains that the Croton valley, with proper storage reservoirs, can abundantly supply the whole city; and that no new aqueduct need be constructed in the present condition of the public debt.

EINE KURZE ALLGEMEINE EINLEITUNG ZU DEN AROMATISCHEN NITROVERBINDUNGEN. Von Peter Townsend Austen. Leipzig, Germany: Winter, Publisher.

We are glad to see that an American is able to publish a very useful chemical treatise in Germany, the great head center of chemistry. Dr. Austen, one of our most distinguished young chemists in the field of original research, has produced a work which bears the marks of much patient thought and study. The book is dedicated to the renowned German chemist, Professor A.W. Hofmann.

OUR YOUNG FOLKS' MAGAZINE: a Monthly Journal of Instruction and Amusement. Subscription price, $1.60 a year. Boston, Mass.: Post Office Box 3090.

A readable little periodical, well calculated to amuse the little ones for whom it is intended.

GLASS FOR THE STUDIO AND DARK ROOM. By Thomas Gaffield. Philadelphia, Pa.: Benerman & Wilson.

There is much useful information in this little pamphlet, and photographers especially should read it. The matter first appeared in the Philadelphia Photographer.

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RECENT AMERICAN AND FOREIGN PATENTS



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NEW AGRICULTURAL INVENTIONS.

IMPROVED GANG PLOW.

Ezra Peak, Montana, Kan.—This invention is so constructed that it may be easily raised from and lowered to the ground, and adjusted to work at any desired depth in the ground. It is claimed to be of lighter draft than plows constructed in the usual way, also to be simple in construction and inexpensive in manufacture. The wheels, the faces of which are notched to give them a slight up-and-down movement as they are drawn forward, slightly jar the plows, and thus cause them to be easier drawn than when smooth wheels are used. The shaft can be provided with a ratchet wheel and pawl to hold it in any position into which it may be turned; and to it is attached a rope or chain, the other end of which, is attached to the forward end of the frame, so that by turning the shaft the plows may be raised from, lowered to, and adjusted to work at any desired depth in the ground.

IMPROVED PLOW.

James Willis Hendley, Cedar Hill, N.C., assignor to David N. Bennett and Samuel T. Wright, of same place.—The objects here are simplicity and cheapness of construction, and such arrangement of parts as will prevent the plow becoming clogged with weeds, etc. The mold-board is welded to the land side, or cast in one piece with it, so that no brace or other connection is required between the mold-board and standard; secondly, the curved beam is attached to the heel of the land-side and supported by a brace, which is bolted to the middle portion of the latter, and arranged in such relation to the mold-board that a space is left between them, into which the trash will fall, and thus be drawn into the furrow and covered.

IMPROVED GRAIN DRILL.

George W. Osborn, Parkville, Mich.—This is an improved attachment for seed drills, for gaging the depth at which the grain shall be deposited in the earth. It consists in an adjustable spring gage bar attached to the shank of each drill tooth, whereby the teeth may be made to enter the ground a greater or less depth. It is claimed to ensure the planting of seeds at equal depth in hard or soft ground, and to diminish the draft.

IMPROVED HORSE HAY RAKE.

Joseph B. Wakeman and John L. Wager, Deposit, N.Y.—The construction of this implement is such that a large space is afforded beneath the rake head for the collection of hay. The pivots of said rake head back are also brought back, so that the teeth may be readily raised to discharge the collected hay. By an ingenious lever arrangement the driver is enabled to hold the rake to its work by the pressure of his foot, and also readily to discharge the hay gathered.

IMPROVED BEE HIVE.

George W. Akins, Bridgeton, Pa.—In this hive, holes are bored in the sides of the compartment for ventilation, and windows are flared for the purpose of inspecting the inside of the hive. A frame is used whenever it is desired to have the honeycomb of any particular shape. It consists of a form of tin or other suitable maternal, placed on a frame or slide, and having the shape required in the comb. Bees will build inside of the form, leaving about one fourth inch space between the form and the comb. The tin sheet receives a portion of the refuse matter, and can be readily taken out and cleaned. On the 1st of May the bees are driven out into another hive and the frames examined. Three frames are taken out and set in a new box, and three empty frames are put in their place. The old queen must be put with the new colony, and half of the bees must be put in each box and shut up, and put on a stand. The hives are to be opened the next morning. At the next natural swarming time the swarms can be again divided. The hive cannot freeze, and it is proof against mice.

IMPROVED PLOW STOCK.

Robert Weber, New Ulm, Texas.—In this invention, by loosening a nut, the point of draft attachment may be raised and lowered to cause the plow to work deeper or shallower in the ground, or turned to one or the other side, to cause the plow to take or leave land, and may be secured in place when adjusted by again tightening the nut.

IMPROVED COMBINED HAY TEDDER AND SIDE RAKE.

John Huber and Henry Snell, Girard, Ill.—This machine may be used simply for stirring up and turning the hay, or for turning the hay and gathering it into windrows. The shaft of a reel revolves in bearings attached to the side bars of the frame near their rear ends. To the bars of the reel are attached spring teeth, which, as the machine is drawn forward, take hold of the hay, carry it up and over the reel, and drop it to the ground in the rear of the machine. A carrier takes the hay from the teeth, when it has been brought to the top of the reel, carries it over the shaft, and discharges it into a trough, down which it slides, and is deposited in a windrow along one side of the path of the machine.

IMPROVED GRUBBING MACHINE.

Ira Burley, Redwing, Minn.—This invention consists in the combination of wheels and axle, tongue, adjusting bar, adjustable brace, uprights, cross bar, two ropes, and four pulley blocks with each other. To the forward end of the tongue is attached a loop or clevis, to receive an iron pin, to be driven into the ground to keep the machine from moving about while being used. To the pulley block is swiveled a hook, to be hooked into a loop, attached to the forward end of a lever. The rear end of the lever passes through a slot in the upper end of a fulcrum post, and has a notch formed in its lower side to receive a bolt or pin, attached to said post to serve as a fulcrum to said lever. Several notches are formed in the lever to receive the fulcrum bolt, to enable the position of the fulcrum post to be adjusted to regulate the leverage, and as circumstances may require. To the lever is attached a strong clevis, to receive the hook of the chain, that is secured to the stump to be pulled.

IMPROVED SEED PLANTER.

Daniel J. Davis, Red Boiling Springs, Tenn.—In this invention two wheels revolve upon the journals of the axle. Upon the end parts of the axle are attached the rear ends of side bars, the forward ends of which are bolted to the outer sides of the forward ends of the plow beams. The forward ends of the beams are bolted to the ends of the front bar, to the center of which is secured the forward end of the central bar. To the beams are attached the plows for opening furrows to receive the seed as it passes from the conductor spouts. The lower ends of the spouts or tubes pass in through the sides of the plows, so as to conduct the seed into the bottom of the furrows before they have been partially filled by the falling in of the soil. The dropping plate is concaved around its dropping holes, and is provided with a plate that may be adjusted to cover one set of dropping holes to drop the hills twice as far apart as when both sets of holes operate.

IMPROVED ANIMAL TRAP.

Thomas N. Hughes, Muddy Creek, Tenn.—This trap is for animals of all kinds, as rats, mice, and larger animals, as foxes, minks, coons, etc., that are allured by bait, and is automatically set again by the animal caught, to be ready for the next animal attracted by the bait. It is divided by a longitudinal partition into two main sections, in which the working parts are disposed. The entrance at the end of one section has a drop door, which is arranged back of the same, resting, when closed, on side strips in inclined position, and being supported on an upright arm, of a centrally pivoted treadle door, at the bottom of the trap, when the trap is set. The treadle door is only required to swing sufficiently on its pivots to release the drop door from the arm, suitable seats at the under side of the trap, at both sides of the treadle door, preventing the door from swinging farther than necessary. The bait is placed, in a grated receptacle, near the treadle door, and entices the animal to pass in, so as to close the drop door when it arrives at the part of the treadle door near the bait. The back end of this section is perforated or grated to admit light, which attracts the frightened animal and induces him to pass toward the light. The top part of the trap may be grated to admit air, and the glass door at the end made to slide, to admit the taking out of the animals for killing them.

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NEW MISCELLANEOUS INVENTIONS.

APPARATUS FOR THE HYDRATION OF CHLORINE GAS.

William Maynard, New York city.—This invention relates to an improved construction of apparatus for the hydration of gases, and more particularly chlorine gas for the manufacture of chlorine water for use in the industrial arts of bleaching, etc. It consists mainly in a case having an inlet for the water above, an inlet for the gas below, and provided with an intermediate water percolating medium; combined with a reservoir located below the level of the case and having a water-sealed communication therewith, which reservoir receives the hydrated gases, and which water seal prevents the heavy gas in the case from passing out through the bottom inlet. The case for the percolation of water and the absorption of the gas is made of conical shape, with the largest diameter at the bottom, to produce the greatest absorption of the heavy gas when first admitted; while horizontal partitions, or shelves, in said case are provided with upwardly projecting tubes which hold a permanent surface of water on the said partition or shelves. The tubes permit, by their peculiar shape, the water to pass down on one side and the gas up on the opposite side of said tube, while their alternating arrangement in the alternating shelves gives a zigzag and long continued passage to the gas and water in moving in opposite directions through the case.

IMPROVED PROCESS OF PREPARING GAS FUEL.

Martin N. Diall, Terre Haute, Ind.—This inventor saturates wood by immersing it in any hydrocarbon oil for from six to twelve hours, as required by the nature of the wood, so that it may take up the necessary quantity of oil for the required strength of gas. The wood is then immersed in a bath of water, for taking up a quantity of water outside the oil, and is then charged in the retorts, the same as coal, and distilled in the same way. By this process the inventor claims that he produces fixed gas equal to coal gas, much faster, and with less expense, the wood and water furnishing the hydrogen, and the oil furnishing the carbon.

IMPROVED FISHING LINE LEADER.

Welmer T. Jahne and Anthony Moors, Jersey City, N.J.—This consists of a leader made of spring wire, bent into V form, provided with a swivel and eye at its middle part, and with eyes or loops at its ends to receive the line and snells. By this construction the snells and hooks will be kept apart however the line maybe thrown, and however they and the leader may be turned about by the tide or current. The device is one well calculated to meet with a favorable reception from fishermen.

IMPROVED ABDOMINAL CORSET.

Christina Lascell, Newark, N.J.—The object of this invention is to furnish an improved abdominal corset, which supports the weight of the abdomen in a perfectly comfortable and easy manner, and throws the strain on the shoulders and hips of the wearer. The corset is adjustable to the varying conditions of the abdomen, does not interfere with the motion and different positions of the body, and is readily put on and taken off. It has adjustable elastic shoulder straps, and opening at the sides by lacings and elastic bands and buttons. The front part of the corset is stiffened by a stay that slides in a pocket to provide for stooping. A central front and lacing admit the front part of the corset to expand. The lower extension part of the corset has short stiffening stays, and it is connected independently of the upper stays by short side lacing and elastic straps to the side or hip parts of the corset. A hernial band extends from the lowermost part of the corset-extension between the legs to the rear, and is attached by adjustable hip straps to the sides of the corset.

IMPROVED FIRE ESCAPE.

John F. Werner, New York city.—The terrible disaster in the Brooklyn theater is serving as a stimulus to induce the invention of devices looking to the prevention of a like occurrence. The present inventor has devised a new fire escape for theaters, concert halls, and other public places of amusement, by which the space at the upper parts of the entrances, halls, or vestibules of the buildings is utilized for the purpose of forming additional passage ways for the persons in the buildings, to be used in case of fire for the more convenient and less dangerous exit of the same. The invention consists, mainly, of a movable floor, suspended by chains, pulleys, and weights, near the ceiling of the entrances, and lowered in case of fire. It is supported on projecting rests of the side walls, at suitable height above the floor. Sliding extensions and swinging stairs and rear sections connect with the ground outside of the door, and with the staircases of the gallery, so as to form separate exits above the regular entrances.

IMPROVED ELECTRO-MAGNETIC DENTAL PLUGGER.

James E. Dexter, New York city.—This invention consists, first, in a magnet having a centrally bored iron core, surrounded by a magnetic coil, which is enveloped by an iron shell that is concentric with the central core, and is attached to a flange formed on the lower end of the said central core. One side of both shell and core are split for the purpose of obviating residual magnetism. The invention also consists in combining a spring yoke, a vibrator, and a spring contact piece, as hereinafter particularly described. The third part of this invention consists in the arrangement of the key for completing the circuit, which is made with an insulating exterior, and is provided with one of the termini of the magnet coil, and bears against the side of the key to insure a constant contact of the surfaces. The various parts of the plugger are combined, so that pressing the key with the finger makes the circuit, and a succession of regular strokes is produced, the force of which may be varied by an adjusting screw.

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NEW MECHANICAL AND ENGINEERING INVENTIONS.

IMPROVED COTTON GIN.

Joseph W. Thorn, Iuka, Miss., assignor to himself and M.W. Beardsley, of same place.—In this machine there is a new construction of the brush drum for simplifying the same, and facilitating the application of the brush wings, so that they can be readily taken off and put on; also, an arrangement of the ribs between the saws for facilitating the separating of the seed from the cotton without breaking and injuring the fiber. There are also ingenious devices for preventing the seed from gathering and clogging at the ends of the saw drum.

IMPROVED SAFETY CHECK FOR ELEVATORS.

Nathan H. Fogg, Boston, Mass.—When the car is suspended normally from the rope, the rubber balls, arranged in sockets near the lower part of the car, are supported on their seats in a state of rest; but the instant that the rope breaks or gets detached from the bolt the action of a spiral spring throws an actuating plate downward, and levers and ball-carrying rods upward. The balls are thus thrown off their seats and wedged between the inclined sides of the pockets and the guide posts of the elevator so as to stop thereby the car.

IMPROVED COMBINATION LOCK.

Achille Parise, Naples, Italy.—This is a new combination lock for doors, trunks, safes, etc., that admits of a large number of combinations, and may be opened and closed quickly. It consists of sliding tumbler plates, having longitudinal slots and a number of perforations placed at different relative positions to the slots of each tumbler. The trunks are connected by screw set pins attached to face slides, and passing through any one of the perforations, admitting the setting of the tumblers and opening of the lock by outer projections or buttons of the slides to fixed exterior guides.

IMPROVED MACHINE FOR WIRING AND BINDING HATS.

Mari A. Cuming and Judson Knight, New York city.—This is a machine for binding hats, felt skirts, and similar articles, by a uniform and parallel pressure on the rims, and by facilitating the applying and taking off of the articles from the machine, and accomplishing the cutting of the binding or braid and wire in a reliable and improved manner. Pressure rollers attach the binding and the wire, if one is required, in connection with a grooved gage that is supported on a seat of the shaft of the lower pressure roller. The wire is guided by annular recesses or chamferings at the rear circumference of the pressure rollers and the groove of the gage. The gage is so connected to its seat that it may be turned and another guide groove of the same be exposed to face the pressure rollers, so as to adapt the same for a variety of work.

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BUSINESS AND PERSONAL

The Charge for Insertion under this head is One Dollar a line for each insertion. If the Notice exceeds four lines, One Dollar and a Half per line will be charged.

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Manufs. of Scissors address J.W.D.E., Harmony Grove, Ga.

For Sale—36 in. Lathe, $4.00; 72 in. Lathe, $4.50; 10 in. Pratt Whiting Shaper, $2.75; 35 H.P. Loco. Boiler, $300; 12 in. Lathe, $65; at Shearman's, 132 N. 3d St., Phila.

Iron Tubing—Wanted, a yearly supply of 1-4 in. light Iron Tubing. Address P.O. box 1250, New York city.

Baxter's Adjustable Wrenches—The best for Farmers, Householders and Mechanics. Greene, Tweed & Co., 18 Park Place, N.Y.

For Sale—Baldwin No. 4 Foot Lathe and fittings; in perfect order. Address P.O. Box 196, Clinton, Mich.

National Steam Pump—Simple, durable, economical. Reduced price. National Iron Works, N. Brunswick, N.J.

Manufs. and dealers in Cotton Gins, Grist Mills, and Rice Hullers and Polishers, address with terms, Y.L. Ridley, Liberty, Texas.

For Sale—Patent Combination Fruit Press, Filter and Funnel. An indispensable article in every household. For circulars, address G.A. Newsam, 118 3d Pl. Brooklyn.

Mill Stone Dressing Diamonds. Simple, effective, and durable. J. Dickinson, 64 Nassau St., N.Y.

Will purchase or introduce, on a reasonable royalty, some good, useful article. Address, with description and full particulars, A.E. Lowison, Boston, Mass.

Mechanical inventors familiar with Envelope Manufacturing. L.J. Henry, 615 Kearny st., San Francisco, Cal.

Set of Mechanical Curves, as illustrated in Sci. Am. Supplement, No. 50, mailed on receipt of $5.25, by Keuffel & Esser, New York.

Hyatt & Co.'s Varnishes and Japans, as to price, color, purity, and durability, are cheap by comparison than any others extant. 246 Grand st., N.Y. Factory, Newark, N.J. Send for circular and descriptive price list.

Lightning Screw Plates. A perfect thread at one cut adjustable for wear. Frasse & Co., 62 Chatham St., N.Y.

Wire Needle Pointer, W. Crabb, Newark, N.J.

Power & Foot Presses, Ferracute Co., Bridgeton, N.J.

Superior Lace Leather, all sizes, cheap. Hooks and Couplings for flat and round Belts. Send for catalogue. C.W. Arny, 148 North 3d St., Philadelphia, Pa.

F.C. Beach & Co., makers of the Tom Thumb Telegraph and other electrical machines, have removed to 530 Water St., N.Y.

For Best Presses, Dies, and Fruit Can Tools, Bliss & Williams, cor. of Plymouth and Jay Sts., Brooklyn, N.Y.

Water, Gas, and Steam Pipe, Wrought Iron. Send for prices. Bailey, Farrell & Co., Pittsburgh, Pa.

Walrus Leather and supplies for polishing Iron, Steel, and Brass. Greene, Tweed & Co., 18 Park Place, N.Y.

Hydraulic Presses and Jacks, new and second hand. Lathes and Machinery for Polishing and Buffing metals. E. Lyon, 470 Grand St., N.Y.

Solid Emery Vulcanite Wheels—The Solid Original Emery Wheel—other kinds imitations and inferior. Caution.—Our name is stamped in full on all our best Standard Belting, Packing, and Hose. Buy that only. The best is the cheapest. New York Belting and Packing Company, 37 and 38 Park Row, New York.

Steel Castings from one lb. to five thousand lbs. Invaluable for strength and durability. Circulars free. Pittsburgh Steel Casting Co., Pittsburgh, Pa.

M. Shaw, Manufacturer of Insulated Wire for galvanic and telegraph purposes, &c., 259 W. 27th St., N.Y.

Shingle, Heading, and Stave Machine. See advertisement of Trevor & Co., Lockport, N.Y.

For Solid Wrought iron Beams, etc., see advertisement. Address Union Iron Mills, Pittsburgh, Pa., for lithograph, etc.

Articles in Light Metal Work, Fine Castings in Brass, Malleable Iron, &c., Japanning, Tinning, Galvanizing. Welles Specialty Works, Chicago, Ill.

See Boult's Paneling, Moulding, and Dovetailing Machine at Centennial, B. 8-55. Send for pamphlet and sample of work. B.C. Mach'y Co., Battle Creek, Mich.

Wanted—Novel and practical invention, by a reliable house, for manufacturing. Address Post Office, Box 25, Chillicothe, Ohio.

Chester Steel Castings Co. make castings twice as strong as malleable iron castings, at about the same price. See their advertisement on page 125.

Hand Fire Engines, Lift and Force Pumps for fire and all other purposes. Address Rumsey & Co., Seneca Falls, N.Y., U.S.A.

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NOTES & QUERIES

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S.J.S. will find good recipes for laundry soaps on pp. 331, 379, vol. 31. For toilet soaps, see p. 289, vol. 28.—B.F.T. will find directions for putting a black finish on brass on p. 362, vol. 25.—J.C.S. will find directions for coloring a meerschaum pipe on p. 90, vol. 36.—A.B. will find a good recipe for Babbitt metal on p. 122, vol. 28.—G.A.D. will find directions for coloring butter with annatto on p. 187, vol. 31.—L.O.J. will find something on iceboats sailing faster than the wind on p. 107, vol. 36.—J.M.L. will find directions for clarifying cotton seed oil on p. 91, vol. 36.—D.V. will find a good recipe for shoe polish on p. 107, vol. 36.—A.B. will find directions for japanning on metal on p. 408, vol. 30.—T.S.D. will find recipes for all kinds of colored fires on p. 203, vol. 34.—G.S.C. can fasten his paper labels to wood with flour paste.—W.R.B. will find directions for dyeing billiard balls on p. 88, vol. 34.—G.W.M. will find directions for making raisins on p. 59, vol. 34.—T.F.T. will find something on burning petroleum in steam boilers on p. 165, vol. 30.—S.B.U. will find some illustrations of lathes for turning spokes, tool handles, etc., on p. 88, vol. 36.—W.E.P. will find a formula for safety valves on p. 330. vol. 32.—A.O. will find directions for removing mildew on p. 138, vol. 27. For mending rubber boots, etc., see p. 203, vol. 30.—W.C.L. will find directions for preserving eggs on p. 306, vol. 34.—R.M.G. will find a recipe for root beer on p. 138, vol. 31.—W.F.H.'s plan for a refrigerator might answer. See p. 251, vol. 31.—J.C. can remove the wool from pelts by steeping the skins in water, and hanging them up till the wool putrifies. Then scrape with a blunt knife. For cleansing wool, see p. 6, vol. 32.—W.H.J. will find a recipe for a cement for marble on p. 344, vol. 32.—T.B. can gild his steel scabbard by following the directions given on p. 106, vol. 34.—A.H.B., J.A.C., W.H.H., J.F.P., D.S., J.N.H., J.P., F.F., M.N., M.C., R.C., K.S.W., T.J., and others, who ask us to recommend books on industrial and scientific subjects, should address the booksellers who advertise in our columns, all of whom are trustworthy firms, for catalogues

(1) R.H.C. says: We have a slate roof which leaks very much. I have not discovered any defect in the way in which it was put on; it appears to be perfect. The pitch may be too low, and the rain may be driven through by the wind on this account. Is there any wash, paint, or cement that might be used for the purpose of remedying this defect? A. There is an india rubber paint which is used to make leaky roofs tight, but we have not learned of its being applied to slate roofs.

(2) C.C.B. says: I am making a small steam engine. The cylinder has, inside diameter, about 1 inch with 21/2 inches stroke. What would be the most suitable material and dimensions for the boiler? A. Make one 10 or 12 inches in diameter and 18 inches high, of 1/8 inch iron. You can carry 60 lbs. steam pressure.

(3) M.C. says: I have had charge of some greenhouses that were erected about four years ago; they are thoroughly heated, and all the pipes have a thick coat of black paint. The houses never gave any satisfaction, no matter how healthy the plants were in the fall. Soon after the fires were lighted both leaves and flowers began to drop, and some plants died. My predecessors attributed it to gas getting into the houses. Upon inquiry I found no gas was there except when the pipes were hot, and that the hotter they were the worse it was. In my opinion, the cause of the trouble was a strong smell of paint from the pipes. Since then I only keep heat enough to save the plants from freezing. A. From your statement there is no doubt that the paint used on the pipes was an imperfectly purified coal tar. Such tar contains a great number of hydrocarbons—naphtha, naphthalen, anthracen, phenol, several organic alkaloids, hydrosulphuric and hydrocyanic acids, etc., all of which are more or less volatile at the temperature to which they must have been subjected. These exhalations have proved fatal to plant life when in sufficient quantity. We do not know of a better remedy than that of removing the cause. Painting the pipes with a strong solution of washing soda and lime would, in a measure, prevent the escape of the most objectionable constituents into the air, by forming with them compounds non-volatile at any temperature to which they are likely to be subjected in contact with the pipes; but the former would be the surest plan.

(4) C.D.W. asks: The roof of the new Illinois State House, as well as the stylobate cornices and upper portion of the dome, are covered with zinc. It has been on about three years, and I am told is materially affected by oxidation. The theory is that zinc, though subject to oxidization, has the peculiarity that the oxide does not scale off as from iron, but forms a permanent coating impervious to the action of the atmosphere. Some mechanics, however, assert that neither zinc, copper, nor lead will withstand the action of our atmosphere, as bituminous coal strongly impregnated with sulphur is almost the only fuel used. It is claimed by some that the sulphurous acid in the atmosphere tends to corrode zinc so as to make it worthless for roofs or gutter linings. A. Are you sure that the roof and gutters in question are not of galvanized iron, iron coated with zinc? This is the material most commonly used for that purpose at the present time. Zinc has been found to be too brittle for the strain to which it is subjected, in such cases, by the expansion and contraction induced by changes of temperature. A slight oxidation will adhere to the surface, but an acid deposit from the atmosphere will penetrate the coating in points and deteriorate the metal.

(5) N.J.S. says: I have a floor of ash and black walnut which has been oiled with raw linseed oil once. How can I finish it so as to get a hard, smooth finish that will not be scratched by boot heels nor be sticky or retain the dirt as a waxed floor does? A. Oil raises the fiber of black walnut and gives it a rougher surface than when free from it. To polish any wood, it is only necessary to fill the pores well, and then rub it down to a smooth surface. Thus painters prefer to put on a coat of shellac varnish first, before oiling walnut and other hard woods. For fine floors, a thin coat of liquid wax is applied as a finish.

(6) A.J.S. asks: What is the best plan for putting up a cheap dry house of lumber, for drying (by steam) white oak, hickory, and other lumber used in wagon and buggy making? A. Make as tight a house as possible with tongued and grooved siding-boards, floors, roof, etc., and provide a stack of steam pipe containing 1 foot of heating surface to every 50 cubic feet of air contained in the building. Set the steam pipe in compact shape and enclose it with a casing of galvanized sheet iron open at the top; supply cold air from outside of the building by a boxed conduit to the bottom of this stack. The air when heated will rise and diffuse itself into the room, and as it cools will fall to the floor; provide registers in the floor, through which it may escape into other boxed tubes under the floor leading to an upright chimney discharging above the roof. Let a smoke pipe from the boiler enter the chimney and extend up inside the flue far enough to heat the same. The change of air is necessary to dry the lumber. The size of the house of course will depend upon the quantity of material required to be stacked up into it at any one time.

(7) G. asks: 1. How do you calculate the amount of pipe of a given size to warm a room of a given size? A. One square foot of plate or pipe surface is generally taken as sufficient to heat about 70 cubic feet of air in dwellings. 2. What allowance should be made for doors and windows? A. The said foot of surface will heat, in accordance with varying conditions, from 40 to 100 cubic feet of air, and allowance should be made for extra exposures, to correspond with that scale. A steam pressure of 5 lbs. is sufficient for heating purposes. 3. What is meant by the terms direct and indirect radiation, in giving capacity of steam generators for heating houses? A. Direct radiation is used when the pipes are located in the room, and indirect when they are located in a chamber in the cellar, to warm air which is conducted to the room by air pipes.

(8) D.M. says: After reading L.S.W.'s reply to J.B.C., p. 75 (6), vol. 36, I think the following demonstration will be more acceptable to J.B.C.: Imagine three spheres of which the given circles are great circles, and a plane tangent to the three spheres. Any two of the spheres may be conceived to have been generated by the revolution of two of the circles about the line joining their centers. During such revolution, the lines tangent to the two circles describe a conical surface. We have, therefore, three spheres and three conical surfaces. Now the plane, which is tangent to the three spheres, is also evidently tangent to the three conical surfaces; and therefore the vertices of those conical surfaces are all in the tangent plane. Now those vertices are the points (1), (2), (3). But the same points are also in the plane passing through the centers of the three spheres, which is the same with the plane of the paper on which the figure is drawn. Those points, being in two planes at the same time, must therefore be in the intersection of those planes, that is to say, in a straight line.

(9) C.W.H. asks: Can dyeing or coloring be done in cold water? A. Many of the coal tar colors may be used in this way: For animal fibers wool, silk, etc. the affinity of these colors is so great that, in most instances, no mordants are necessary. The baths are usually made slightly acid. With vegetable fibers, however, a fast dye is not assured without mordanting. Some of the finer goods are prepared by treating with steam coagulated albumen (animalizing), gelatin, various tannates, tin salt, alum, and other metallic salts. The following is, the usual method of treatment, except with goods intended for very light shades: Pass the goods through a strong decoction of sumac or other tannin solution for an hour, and afterwards for an hour or two through a weak solution of stannate of soda; wring out, dip into a dilute solution of sulphuric acid, and rinse well in water. The goods are then ready to be passed through the color bath, slightly acidulated. For different tints, these baths are worked at different temperatures.

(10) F.W. says: I wish to lay the face tier of a brick wall in black mortar. How can I make the coloring material and mix it? A. Some prefer to use red mortar and afterwards pencil the joints with black. Color the ordinary white mortar with Spanish brown for red mortar, and with ivory black for black, by mixing in enough of the color in a powdered state to give a good deep tone.

(11) H.A.S. asks: 1. How many prisms are required in a spectroscope to detect mineral elements in presence of all the ash ingredients of organic bodies? A. If we understand you, one 60 deg. prism will answer. 2. What is the best and cheapest form of apparatus to heat such compounds for examination? A. Mix the substance with a little pure hydrochloric acid and glycerin, and introduce into the flame on a coil of platinum wire.