COMMENTS ON SULPHATE OF COPPER EXPERIMENTS.

The first experiment was carried out by Mr. W.W. Evans, on the Southern Railway of Chili, in 1857, and he informs your committee that in 1860, when he left that country, the ties were still good and in serviceable condition.

We give herewith, in Appendix No. 16, an interesting letter from Mr. E. Pontzen to Mr. Evans, on the subject of the Boucherie process.

Experiments Nos. 2 to 16, inclusive, were all tried with various modifications of the sulphate of copper process as introduced by Mr. W. Thilmany in this country. They date back to 1870 (experiment No. 2), when Mr. Thilmany was working and recommending the methods of vital suction and of the Boucherie hydraulic pressure system. After describing the foreign methods of injection with sulphate of copper, he states in his first pamphlet (1870): "This process resulted very satisfactorily, but it was found that the sulphate of copper became very much diluted by the sap, and when the same liquid was used several times, the decaying substance of the sap, viz., the albumen, was reintroduced into the wood, and left it nearly in its primitive condition."

He accordingly proposed a double injection, first by muriate of barytes, and, secondly, by sulphate of copper, forced through by the Boucherie process, and it is presumed that the ties of 1870, in experiment No. 2, which showed favorable results when examined in 1875, were prepared by that process.

Subsequently Mr. Thilmany changed his mode of application to the Bethell process of injecting solutions under pressure in closed cylinders, and probably the paving blocks for experiment No. 3 were prepared in that way. The chemical examination of them by Mr. Tilden, however, showed the "saturation very uneven; absorptive power, high; block contains soluble salts of copper, removable by washing."

It was expected that the double solution, by forming an insoluble compound, would prove an effective protection against the teredo. Experiments Nos. 4, 5, 6, and 8, however, proved the contrary to be the fact.

The process, when well done, gave moderately satisfactory results against decay. A pavement laid in the yard of the Schlitz Brewing Company, in Milwaukee (experiment No. 7), was sound in 1882, after some six years' exposure. A report by Mr. J.F. Babcock, a chemist of Boston (experiment No. 9), indicated favorable results, and the planks in a ropewalk at Charlestown (experiment No. 15), laid in 1879, were yet sound in 1882.

The experiments on railroad ties (Nos. 10, 11, 12, 13, 14, and 16), however, did not result satisfactorily. They seemed favorable at first, and great things were expected of them; but late examinations made on the Wabash Railroad, on the New York, Pennsylvania, and Ohio, and on the Cleveland and Pittsburg Railroad, have shown the ties to be decaying, and the results to be unfavorable.

This applies to the sulphate of copper and barium process. Mr. Thilmany has patented still another combination, in which he uses sulphate of zinc and chloride of barium, which has been noticed under the head of burnettizing.

Experiment No. 17 was tried on the Hudson River Railroad. It consisted of 1,000 sap pine ties, which had been impregnated in the South, by the Boucherie process, with a mixture of sulphate of iron and sulphate of copper, under Hamar's patent. These ties were laid in the tunnel at New Hamburg, a trying exposure, and when examined, in 1882, several of them were still in the track. The process, however, was found to be so tedious that it was abandoned after a year's trial, and has not since been resumed.

In 1882 Mr. H. Fladd, of St. Louis, patented a method which is the inverse of the Boucherie process (experiment No. 18). To the cap fastened to the end of a freshly cut log he applies a suction pump, and placing the other end into a vat, filled with the desired solution, he sucks up the preserving fluid through the pores or sap cells of the wood.

Quite a number of experimental ties have been prepared in this way, with various chemical solutions, chief of which was sulphate of copper, and there is probably no question but that the life of the wood will be materially increased thereby.

Whether the process will prove more convenient and economical than the original Boucherie process can only be determined by practical application upon an extensive scale.

A considerable number of modifications and appliances for working the Boucherie process have been patented in this country; but none of them seems to have come into practical use, probably because of the necessity for operating upon freshly cut logs, and the inconvenience of such applications.

The table on this page gives a record of various experiments with miscellaneous substances.

RECORD OF AMERICAN EXPERIMENTS—MISCELLANEOUS.

+ + + -+ -+ + -+ - Material Subsequent No Locality Year Process. Treated. Exposure Results. Authority. + + + -+ -+ + -+ - 1 Chestnut 1839 Earle's Hemlock Paving Failure S.V. Beuet Street, blocks Philadelpha 2 Watervliet 1840 " Oak Gun " " Arsenal timber carriage 3 Delaware & 1840 " Rope Fungus Favorable " Hudson pit Canal 4 Philadelphia 1840 Lime bath Pine Railroad Unfavor. M. Coryell & Columbia stringers track Railroad 5 Boston & 1844 Sulphate Ties " " I. Hinckley Providence of iron Railroad 6 Belvedere 1850 Salt Hemlock " " M. Coryell Railroad 7 Baltimore 1850 Lime Ties " " J.L. Randolph & Ohio Railroad 8 Rochester 1852 Payenizing Ties " " T. Hilliard 9 Germantown, 1855 Charring Fence Fence Favorable G. McGrew Ind. posts 1879 10 Pottsville, 1857 Pyrolig'ite Timber Railroad Unfavor. H.K. Nichols Pa. of iron sills 11 Erie Railway 1858 Boring " Bridges Favorable H.D.V. Prait 12 Galveston 1867 Casing Piles Bridge Failure W.H. Smith 13 New York 1868 Beerizing Lumber Signs Doubtful S. Beer 14 Wyoming 1868 Natural Ties Railroad Preserved J. Territory soil track Blinkinsderfer 15 Chicago, 1870 Foreman- Timber Steamboat Favorable M.B. Brown Ill. izing 1879 16 Illinois 1871 " Ties Railroad Failure L.P. Morehouse Central track Railroad 17 St. Louis 1871 " Shingles Roof " F. De Funiak 18 Memphis & 1871 " Ties Railroad " F. De Funiak Charleston track 19 Washington, 1871 Tripler Paving Laboratory " W.C. Tilden D.C. blocks 20 " 1872 Samuel " " " " 21 " 1872 Taylor " " " " 22 " 1872 Waterbury " " " " 23 " 1872 Sulphate " Pennsyl- " J.A. Partridge of iron vania Ave 24 " 1872 Samuel " F. Street " " 25 " 1872 Samuel " 16th St. " " 26 Norvolk, Va. - Red lead Pine and Teredo " P.C. Asserson oak 27 " - White zinc " " " " 28 " - Tar and " " " " plaster 29 " - Kerosene " " " " 30 " - Rosin and " " " " tallow 31 " - Fish oil & " " " " tallow 32 " - Verdigris " " " " 33 " - Bark on " " Good for " pile 5 years 34 " - Carbolic " " Failure " acid 35 " - Tar and " " " " cement 36 " - Davis' " " " " compound 37 " - Carbolized " " " " paper 38 " - Paint " " " " 39 " - Thilmany " " " " 40 " - Vulcanized " " " " fiber 41 " - Charring " " Good for " 9 years 42 New Orleans 1872 " Piles " Failure J.W. Putnam & Mobile R.R. 43 " 1872 " & " " Temporary " oiling prot'n 44 Galveston & 1870 Charring " " " " Houston 1874 R.R. + + + -+ -+ + -+ -

COMMENTS ON MISCELLANEOUS EXPERIMENTS.

Experiments Nos. 1, 2, and 3 relate to the Earle process, from which great results were expected from 1839 to 1844. It consisted in immersing timber, rope, canvas, etc., in a hot solution of one pound of sulphate of copper and three pounds of sulphate of iron mixed in twenty gallons of water. It was first tested on some hemlock paving blocks on Chestnut Street, Philadelphia, and for a time seemed to promise good results. Experiments with prepared rope, exposed in a fungus pit, by Mr. James Archbald, Chief Engineer of the Delaware and Hudson Canal, seemed also favorable.

The process was, therefore, thoroughly tried at the Watervliet Arsenal, where it was applied to some 63,000 cubic ft. of timber, at a cost of about seven cents per cubic foot. The timber was used for various ordnance purposes, and while it was found to have its life extended, as would naturally be expected from the known character of the antiseptics used, its strength was so far impaired, and it checked and warped so badly, that the process was abandoned in 1844.

The committee is indebted to General S.V. Benet, Chief of Ordnance, for a full copy of the reports upon these experiments.

Experiments Nos. 4 and 7 represent the lime process, which has been applied to a considerable extent in France. The fact that platforms and boxes used for mixing lime mortar seem to resist decay has repeatedly suggested the use of lime for preserving timber. In 1840 Mr. W.R. Huffnagle, Engineer of the Philadelphia and Columbia Railroad, laid a portion of its track on white pine sills, which had been soaked for three months in a vat of lime-water as strong as could be maintained. Similar experiments were tried on the Baltimore and Ohio in 1850. The result was not satisfactory, as might be expected from the fact that lime is a comparatively weak antiseptic (52.5 by atomic weight, while creosote is 216), and from the extreme tediousness of three months' soaking.

Experiments Nos. 5 and 8 were tried with sulphate of iron, sometimes known as payenizing, and the particulars of the former have been furnished by Mr. I. Hinckley, President of the Philadelphia, Wilmington, and Baltimore Railroad, to whom your committee is much indebted for a large mass of information on the subject of timber preservation.

Mr. Hinckley has had longer and more varied experience on this subject than any other person in this country. Beginning with sulphate of copper in 1846, following with chloride of mercury in 1847, and chloride of zinc in 1852, going back to chloride of mercury, and again to chloride of zinc, using the latter until 1865, then using creosote to protect the piles against the teredo at Taunton Great River (experiment No. 2. creosoting), he has had millions of feet of timber and lumber prepared by the various processes, and has kindly placed at our disposal many original reports in manuscript and pamphlets which are now very rare.

Experiment No. 6 was made by Mr. Ashbel Welch, former President of this Society, and consisted in boring hemlock track sills 6 x 12 with a 1-1/8 inch auger-hole 10 inches deep every 15 inches. These were filled with common salt and plugged up, as is not infrequently done in ship-building, but while the life of the timber was somewhat lengthened, it was concluded that the process did not pay.

Salt has been experimented with numberless times. It is cheap, but is a comparatively weak antiseptic, its atomic weight being 58.8 in the hydrogen scale, as against 135.5 for chloride of mercury.

Experiment No. 9 is included in order to notice the well-known and most ancient process of charring the outside of timber. In this particular case, the fence posts after charring were dipped for about three feet into a hot mixture of raw linseed oil and pulverized charcoal, which probably acted by closing the sap cells against the intrusion of moisture, which, as is well known, much hastens decay. The posts, which had been set butt-end upward, were mostly sound in 1879, after 24 years' exposure.

Experiments Nos. 41, 42, 43, and 44 did not, however, result as well, and numberless failures throughout the country attest that charring is uncertain and disappointing in its results.

Much ingenuity has been wasted in devising and patenting machinery for charring wood on a large scale to preserve it against decay. The process, however, is so tedious in comparison with the benefits which it confers, and the charred surface is so objectionable for many uses, that nothing is to be expected from the process upon a large commercial scale.

In 1857-58 Mr. H.K. Nichols tried sundry experiments (No. 10), at Pottsville, Pa., upon timber which he endeavored to impregnate with pyrolignite of iron by means of capillary action. Similar experiments had previously been thoroughly tried in France by Dr. Boucherie, but the result has not been found satisfactory.

In 1858 the Erie Railway purchased the right of using the Nichols patent, and erected machinery at its Owego Bridge shop for boring a 2 inch hole longitudinally through the center of bridge timbers. This continued till 1870, when the works were burned, and in rebuilding them the boring machinery was not replaced. The longitudinal hole allowed a portion of the sap to evaporate without checking the outside of the timber, and undoubtedly lengthened its life. It is believed there are yet (1885) some sticks of timber in the bridges of the road that were so prepared in 1868 or 1869.

In 1867 Mr. W.H. Smith patented a method of preserving timber, by incasing it in vitrified earthenware pipes, and filling the space between the timber and the pipe with a grouting of hydraulic cement. This was applied to the railroad bridge connecting the mainland with Galveston Island (experiment No. 12), and so well did it seem to succeed at first that it was proposed to extend the process to railroad trestlework, to fencing, to supports for houses, and to telegraph poles. But after a while the earthenware pipes were displaced and broken, the process was given up, and Galveston bridge is now creosoted.

In 1868 Mr. S. Beer patented a process for preserving wood by simply washing out the sap from its cells. Having ascertained that borax is a solvent for sap, he prepared a number of specimens by boiling them in a solution of borax. For small specimens, this answered well, and a signboard treated in that way (experiment No. 13) was preserved a long time; but when applied to large timber, the process was found very tedious and slow, and no headway has been made in introducing it.

Experiment No. 14 was brought about by accident. Some years age it was discovered that there was a strip of road in the track of the Union Pacific Railroad, in Wyoming Territory, about ten miles in length, where the ties do not decay at all. The Chief Engineer, Mr. Blinkinsderfer, kindly took up a cotton wood tie in 1882, which had been laid in 1868, and sent a, piece of it to the committee. It is as sound and a good deal harder than when first laid, 14 years before, while on some other parts of the road cottonwood ties perish in two or five years.

The character of the soil where these results have been observed is light and soapy, and Mr. E. Dickinson, Superintendent of the Laramie Division, furnishes the following analysis:

Sodium chloride 10.64 Potassium 4.70 Magnesium sulphate 1.70 Silica 0.09 Alumina 1.94 Ferric oxide 5.84 Calcium carbonate 22.33 Magnesium 3.39 Organic matter 4.20 Insoluble matter 941.47 Loss in analysis 4.00 Traces of phosphorous acid and ammonia.

The following remarks made by the chemists who made the analysis may be of interest:

"The decay of wood arises from the presence in the wood of substances which are foreign to the woody fiber, but are present in the juices of the wood while growing, and consist of albuminous matter, which, when beginning to decay, causes also the destruction of the other constituents of the wood."

"One of the means adopted to prevent the destruction of wood by decay is by the chemical alteration of the constituents of the sap."

"This is brought about by impregnating the wood with some substance which either enters into combination with the constitutents of the sap or so alters their properties as to prevent the setting up of decomposition."

"The analysis of this soil shows that it contains large quantities of the substances (sodium, potassium chloride, calcium, and iron) most used in the different processes of preserving or kyanizing wood. It also contains much inorganic matter, which also acts as a preserving agent."

Some of the ties so preserved have been transferred to other portions of the track, and some of the soil has also been transported to other localities, so that it is hoped that in the discussion that may be expected to follow this report, some further light will be thrown on the subject by an account of the results of these experiments.

Experiments Nos. 15, 16, 17, and 18 are most instructive, and convey a useful lesson.

In 1865 Mr. B.S. Foreman patented the application of a dry powder for preserving wood, which was composed of certain proportions of salt, arsenic, and corrosive sublimate. This action was based upon an experience which he had had when, as a working mechanic of Ellisburg, Jefferson County, N.Y., in 1838, he had preserved a water-wheel shaft by inserting such a compound in powder in the body of the wood, and ascertained that it was still sound some 14 years later.

His theory of the action of his compound upon timber was briefly this:

"That all wood before it can decay must ferment; that fermentation cannot exist without heat and moisture; that the chemical property or nature of his compound, when inserted dry into wood, is to attract moisture, and this moisture, aided by fermentation, liquefies the compound; that capillary attraction must inevitably convey it through the sap ducts and medullary rays to every fiber of the stick.... Were these crystallizations salt alone, they would soon dissolve, but the arsenic and corrosive sublimate have rendered them insoluble; hence they remain intact while any fiber of the wood is left."

"The antiseptic qualities of arsenic are also well known, and have been known for centuries. Chemical analysis of the mummies of Egypt to-day shows the presence of arsenic in large quantities in every portion of their substance. Whatever other ingredients may have entered into the compound that has been so potent in preserving from decay the bodies of the old kings of Egypt, and even the linen vestments of their tombs, arsenic was most certainly one."

The mode of application used by Mr. Foreman was to bore holes two inches in diameter three-fourths of the way through sticks of square timber, four feet apart, to fill them with the dry powder, and to plug them up with a bung. For railroad ties he bored two holes two inches in diameter, six inches inside of the rails, and filled and plugged them. Fresh cut lumber and shingles were prepared by piling layers upon each other with the dry powder sprinkled between in the ratio of twenty pounds to the thousand feet of lumber. This was allowed to remain at a temperature of at least 458 deg. F. until fermentation took place, when the lumber was considered fully "foremanized."

The process was first applied to the timber and lumber for a steamboat, and in 1879 the result was reported to be favorable. It was then applied to some ties on the Illinois Central Railroad, where it did not succeed, and to some on the Chicago and Northwestern, where they seem to have been lost sight of, being few in number, so that your committee has not been able to learn the result.

Great expectations were, however, entertained, and a conditional sale was made to various parties of the right of using the process, notably, it is said, to the Memphis and Charleston Railroad for $50,000; and some ten miles of ties were prepared on that road, when the poisonous nature of the ingredients used brought about disaster.

Some shingles were prepared for a railroad freight house at East St. Louis, but all the carpenters who put them on were taken very ill, and one of them died.

The arsenic and corrosive sublimate effloresced from the ties along the Memphis and Charleston Railroad. Cattle came and licked them for the sake of the salt, and they died, so that the track for ten miles was strewed with dead cattle. The farmers rose up in arms, and made the railroad take up and burn the ties. The company promoting foremanizing was sued and cast in heavy damages, and it went out of business.

In 1870 Mr. A.B. Tripler patented a mixture of arsenic and salt, and the succeeding year a specimen of wood prepared under that patent was submitted to the Board of Public Works of Washington, D.C., and examined by its chemist, Mr. W.C. Tilden (experiment 19). He found the impregnation uneven, and the absorptive power high, but he did not find any arsenic, though its use was claimed.

The Samuel process (experiment 20) consisted in the injection, first, of a solution of sulphate of iron, and afterward of common burnt lime. Mr. Tilden reported the wood to be brittle, and the water used to test the absorptive power to have been filled with threads of fungi in forty-eight hours.

The Taylor process (experiment No. 21) used a solution of sulphide of calcium in pyroligneous acid. It was condemned by Mr. Tilden.

The Waterbury process (experiment 22) consisted in forcing in a solution of common salt, followed by dead oil or creosote. It was also condemned by Mr. Tilden.

The examinations of Mr. Tilden extended to some fourteen different processes, most of which have already been noticed in this report, and their practical results given.

The Board of Public Works, however, laid down a considerable amount of prepared wood pavement in Washington, all of which is understood to have proved a dismal failure. After a good deal of inquiry, your committee has been enabled to obtain information of the results of three of these experiments.

The pine paving blocks upon Pennsylvania Avenue (experiment 23) were first kiln-dried, and then immersed in a hot solution of sulphate of iron.

The spruce blocks on E Street (experiment 24) were treated with chloride of zinc, or, in other words, burnettized; but the mode of application is not stated.

The pine blocks upon Sixteenth Street (experiment 25) were treated with the residual products of petroleum distillation. It is stated that this was the only process in which pressure was used.

In from three and a half to four and a half years the blocks were badly decayed, and large portions of the streets were almost impassable, while other streets paved in the same year with untreated woods remained in fair condition.

It has been stated to your committee that this result, which did much toward bringing all wood preserving processes into contempt, was chiefly owing to the very dishonest way in which the preparation was done; that in fact there was a combination between the officials and the contractors by which the latter were chiefly interested "how not to do it," and that the above results, therefore, prove very little on the subject of wood preservation.

Through the kindness of the United States Navy Department your committee is enabled to give the results of a series of experiments (Nos. 26 to 41 inclusive) which have been carried on at the Norfolk, Va., Navy Yard, for a series of years, by Mr. P.C. Asserson, Civil Engineer, U.S.N., to test the effect of various substances as a protection against the Teredo navalis. It will be noticed that the application of two coats of white zinc paint, of two coats of red lead, of coal tar and plaster of Paris mixed, of kerosene oil, of rosin and tallow mixed, of fish oil and tallow mixed and put on hot, of verdigris, of carbolic acid, of coal tar and hydraulic cement, of Davis' patent insulating compound, of compressed carbolized paper, of anti-fouling paint, of the Thilmany process, and of "vulcanized fiber," have proved failures.

The only favorable results have been that oak piles cut in the month of January and driven with the bark on have resisted four or five years, or till the bark chafed or rubbed off, and that cypress piles, well charred, have resisted for nine years.

This merely confirms the general conclusion which has been stated under the head of creosoting, that nothing but the impregnation with creosote, and plenty of it, is an effectual protection against the teredo. Numberless experiments have been tried abroad and in this country, and always with the same result.

There are quite a number of other experiments which your committee has learned about which are here passed in silence. The accounts of them are vague, or the promised results of such slight importance as not to warrant cumbering with them this already too voluminous report.

The committee also forbears from discussing the merits of the many patents which have been taken out for wood preservation. It had prepared a list of them, and investigated the probable success of many of them, but has concluded that it is better to confine itself to the results of actual tests, and to stick to ascertained facts.

Neither does the committee feel called upon to point out the great importance of the subject, and the economical advantages which will result from the artificial preparation of wood as its price advances. They hope, however, that the members of this Society, in discussing this report, will dwell upon this point.

We shall instead give as briefly as possible the general conclusions which we have reached as the result of our protracted investigation.

DECAY OF TIMBER.

Pure woody fiber is said by chemists to be composed of 52.4 parts of carbon, 41.9 parts of oxygen, and 5.7 parts of hydrogen, and to be the same in all the different varieties. If it can be entirely deprived of the sap and of moisture, it undergoes change very slowly, if at all.

Decay originates with the sap. This varies from 35 to 55 per cent. of the whole, when the tree is felled, and contains a great many substances, such as albuminous matter, sugar, starch, resin, etc., etc., with a large portion of water.

Woody fiber alone will not decay, but when associated with the sap, fermentation takes place in the latter (with such energy as may depend upon its constituent elements), which acts upon the woody fiber, and produces decay. In order that this may take place, it is believed that there must be a concurrence of four separate conditions:

1st. The wood must contain the elements or germs of fermentation when exposed to air and water.

2d. There must be water or moisture to promote the fermentation.

3d. There must be air present to oxidize the resulting products.

4th. The temperature must be approximately between 50 deg. and 100 deg. F. Below 32 deg. F. and above 150 deg. F., no decay occurs.

When, therefore, wood is exposed to the weather (air, moisture, and ordinary temperatures), fermentation and decay will take place, unless the germs can be removed or rendered inoperative.

Experience has proved that the coagulation of the sap retards, but does not prevent, the decay of wood permanently.[1] It is therefore necessary to poison the germs of decay which may exist, or may subsequently enter the wood, or to prevent their intrusion, and this is the office performed by the various antiseptics.

[Footnote 1: Angus Smith, 1869, "Disinfectants." S.B. Boulton, 1884, Institution Civil Engineers, "On the Antiseptic Treatment of Timber."]

We need not here discuss the mooted question between chemists, whether fermentation and decay result from slow combustion (eremacausis) or from the presence of living organisms (bacteria, etc.); but having in the preceding pages detailed the results of the application of various antiseptics, we may now indicate under what circumstances they can economically be applied.

(To be continued).

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THE SPAN OF CABIN JOHN BRIDGE.

To the Editor of the Scientific American Supplement:

Your issue of 17th October contains the fifth or sixth imprint of Mr. B. Baker's, C.E., recent address at the British Association of Aberdeen which has come into my hands.

In speaking of stone bridges, he alludes to the bridge over the Adda as 500 years old. It was never more than 39 years old as stated in the same address, and he belittles the American Cabin John Bridge by making its span "after all only 215 ft." As the builder of this greatest American stone arch, I regret that on so important and public an occasion the writer was not accurate.

The clear span of Cabin John Bridge is 220 ft. The difference is not great, but in the length of a bridge span it is the last foot that counts, as in an international yacht race to be beaten by one minute is to fail to capture the cup.

M.C. MEIGS.

Washington, D.C., Oct. 16, 1885.

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THE GERMAN CORVETTE AUGUSTA.

On the 3d of June of this year, the German cruising corvette Augusta left the island of Perrin, in the Straits of Bab el Mandeb, for Australia; and as nothing has been heard of her since that day, the report that she was destroyed in the typhoon on June 3 is probably correct. The vessel left Kiel on April 28, with the crews for the cruisers of the Australian squadron; 283 men were on board, including the commander, Corvette Captain Von Gloeden. There is still a possibility that the Augusta was dismasted, and is drifting somewhere in the Indian Ocean, or has stranded on an island; but this is not very probable, as the Augusta was not well adapted to weather a typhoon. During her cruise of 1876 to 1878, all the upper masts, spars, etc, had to be removed, that she might be better adapted to weather a cyclone or like storm. If the Augusta had not met with an accident, she would have arrived at Port Albany in Australia by the 30th of June or beginning of July. She was due June 17.

The Augusta was built at Armands' ship yards at Bordeaux, and was bought in 1864 by Prussia. She was a screw steamer with ship's rigging, 2371/2 feet long, 351/2 feet beam, 16 feet draught, and 1,543 tons burden. Her engines had 400 horse-power, and her armament consisted of 14 pieces.



During the Franco-German war of 1870-71, she was commanded by Captain Weikhmann, and captured numerous vessels on the French coast. January 4, 1871, she captured the French brig St. Marc, in the mouth of the Gironde; the brig was sailing from Dunkirken to Bordeaux with flour and bread for the Third French Division. The Augusta then captured the Pierre Adolph, loaded with wheat, which was being carried from Havre to Bordeaux. Then the French transport steamer Max was captured and burned. The French men of war finally forced the Augusta to retreat into the Spanish port of Vigo, from which she sailed Jan. 28, and arrived March 28 at Kiel, with the captured brig St. Marc in tow.—Illustrirte Zeitung.

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IMPROVEMENT IN METAL WHEELS.

In the Inventions Exhibitions may be seen a good form of metal wheel, the invention of Mr. H.J. Barrett, of Hull, Eng., and which we illustrate.



Fig. 1 is a perspective view of the wheel, Fig. 2 a transverse section, and Fig. 3 a longitudinal section of the boss. These wheels are made in two classes, A and B. Our engraving illustrates a wheel of the former class, these wheels being designed for use on rough and uneven roads, and when very great jolting strains may be met with, being stronger than those of class B design. The wheels are made with mild steel spokes, which are secured by metal straps in the recesses cut in the annular flanges on the boss, and by a taper bolt or rivet through the tire and rim. These spokes can be easily taken out and renewed when necessary by any unskilled person in a few minutes. The spokes being twisted midway of their length give greater strength to the wheel and power to resist side strains in pulling out of deep ruts or holes, without increasing the weight. The bosses and straps are made of malleable iron, in which the metal bushes are secured by means of a key with a washer screwed up on the front end. They are also fitted with steel oil caps to the end of the bushes, which are provided with a small set screw, so that the cap need not be taken off when it is necessary to lubricate the wheel, as by simply taking out the set screw oil may be poured through the hole into the cap. The set screw also forms a fulcrum for a key, so that the cap can be taken off or put on when required, as well as a means of preventing the cap being lost by shaking loose on rough roads. In all hot and dry climates, the continued shrinking of wood wheels and loosening of the tires is a constant source of expense and inconvenience. This wheel having a tire and rim entirely of metal does away with the difficulty, as the expansion and contraction are equal, consequently the tires need only be removed when worn out, and others can be supplied, drilled complete, ready for putting on, which can be done by any unskilled person. The wheels of class B design are the same in principle of construction as those of class A, but they have cast metal bosses or naves, without loose bushes, and are suitable for general work and ordinary roads where the strains are not so severe. The bosses or naves are readily removed in case of breakage, and they can be fitted with steel oil caps for lubricating.—Iron.

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APPARATUS FOR THE PRODUCTION OF WATER GAS.

The apparatus shown in the accompanying engraving is designed for the manufacture of water gas for heating purposes, and is described in a communication, by Mr. W.A. Goodyear, to the American Institute of Mining Engineers.

The generator, A, is lined with refractory bricks and is filled with fuel, which may be coal, coke, or any suitable carbonaceous material. B and B' are two series of regenerating chambers lined with refractory brick, and, besides, filled with refractory bricks piled up as shown in the figure. The partitions, C and C', are likewise of refractory brick, and are rendered as air-proof as possible. Apertures, D and D', are formed alternately at the base of one partition and the top of the adjacent one, in order to oblige the gases that traverse the series of chambers to descend in one of them and to rise in the following, whatever be the number of chambers in use.

The two flues, E and E', lead from the bottom of the two nearest regenerator on each side to the bottom of the generator A, and serve to bring the current of air or steam into contact with the fuel. Valves, F and F', placed in these flues, permit of regulating the current in the two directions. Pipes, M and M', provided with valves, G and G', put the upper part of the generator in communication with the contiguous chambers, T and T'. Other pipes, N and N', with valves, H and H', permit of the introduction of a current of air from the outside into the chambers, T and T'. The pipes, O and O', and the valves, I and I', connected with a blower, serve for the same purpose. The pipes, P and P', and their valves, J and J', lead a current of steam. The conduits, Q and Q', and their valves, K and K', direct the gases toward the purifiers and the gasometer. Finally, the pipes, R and R', provided with valves, L and L', are connected with a chimney.

The generator, A, is provided at its upper part with a feed hopper. The doors, S and S', of the ash box close the apertures through which the ashes are removed.

When it is desired to use the apparatus, the pipes, P, Q, and R, are closed by means of their valves, J, K, and L, and the valve, I, of the pipe, O, is opened. The pipes, M and N, are likewise closed, while the flue, E, is opened. On the other side of the generator the reverse order is followed, that is to say, the flue, E', is closed, the pipes, M' and N', are opened, the pipes, O', P', and Q', are closed, and R' is opened.

A current of air is introduced through the pipe, O, and this traverses the regenerators, B, enters the chamber, T, and the generator, A, through the flue, E. As this air rises through the mass of incandescent fuel, its oxygen combines with an atom of carbon and forms carbonic oxide. This gas that is disengaged from the upper part of the fuel consists chiefly of nitrogen and carbonic oxide, mixed with volatile hydrocarburets derived from the fuel used. This gas, through the action of the air upon the fuel, is called "air gas," in order to distinguish it from the "water gas" formed in the second period of the process.

The air gas, on issuing from the generator through the pipe, M', in order to pass into the chamber, F', meets in the latter a second current of air coming in through the pipe, N', and which burns it and produces, in doing so, considerable heat. The strongly heated gases resulting from the combustion traverse the regenerators, B', and give up to the bricks therein the greater part of their heat, and finally make their exit, relatively cool, through the pipe, R', which leads them to the chimney. When the operation has been continued for a sufficient length of time to give the refractory bricks in the chamber, B', next the regenerator a high temperature, the valve, I, is closed, thus shutting off the entrance of air through the pipe, Q. The valve, F, of the flue, E, is also closed, and that of the pipe, M, is opened. The valves, G', H', L', of the pipes, M', N', R', are closed, and that, F', of the flue, E', is opened. The valve, J', of the pipe, P', is then opened, and a jet of steam is introduced through the latter.

The steam becomes superheated in traversing the regenerators, B', and in this state enters the bottom of the generator through the flue, E'. In passing into the incandescent fuel that fills the generator, the steam is decomposed, and there forms carbonic oxide, while hydrogen is liberated. The mixture of these two gases with the hydrocarburets furnished by the fuel constitutes water gas. This gas on making its exit from the generator through the pipe, M', passes through the chambers, B, and abandons therein the greater part of its heat, and enters the pipe, R, whence it passes through Q into the purifiers, and then into the gasometer.

As the production of water gas implies the absorption of a large quantity of sensible heat, it is accompanied with a rapid fall of temperature in the chambers, B', and eventually also in the generator, A, while at the same time the chambers, B, are but moderately heated by the sensible heat of the current of gas produced. When this cooling has continued so long that the temperature in the generator, A, is no longer high enough to allow the fuel to decompose the steam with ease, the valve, J', of the pipe, P', that leads the steam is closed, as is also the valve, K, of the pipe, Q, while the valves, L and H, of the pipes, R and N, are opened. After this the valve, I', is opened, and a current of air is let in through the pipe, O'. This air, upon traversing the chambers, B' and T', is raised to a high temperature through the heat remaining in these chambers, and then enters at the bottom of the generator, through the flue, E'. The air gas that now makes its exit from the pipe, M, in the chamber, T, meets another current of air coming from the pipe, N, and is thus burned. The products resulting from such combustion pass into the chambers, B, and then into the chimney, through the pipe, R. The temperature then rapidly lowers in the chambers, B', and rises no less rapidly in the generator, A, while the chambers, B, are soon heated to the same temperature that first existed in the chambers, B'. As soon as the desired temperature is obtained in the generator, A, and the chambers, B, the air is shut off by closing the valve, I', of the pipe, O'; the valve, F', of the flue, E', is also closed, the valves, G' and K', of the pipes, M' and Q', are opened, the valves, G, H, and L, of the pipes, M, N, and R, are closed, and the valve, F, of the flue, E, and the valve, J, of the pipe, P, are opened. A current of steam enters the apparatus through the pipe, P, traverses the chambers, B, and enters the generator through the flue, E. The gas produced makes its exit from the generator, passes through the pipe, M', and the chambers, T' and B', and the pipe, R, and enters the gasometer through the pipe, Q'.



When the chamber, B, and the generator, A, are again in so cool a state that the fuel no longer decomposes the steam easily, the valves are so maneuvered as to stop the entrance of the latter, and to send a current of air into the apparatus in the same direction that the steam had just been taking. The temperature thereupon quickly rises in the generator, A, while, at the same time, the combustion of the air gas produced soon reheats the chambers, B'. The cooled products of combustion go, as before, to the chimney. The position of the valves is then changed again so as to send a current of steam into the apparatus in a direction contrary to that which the air took in the last place, and the water gas obtained again is sent to the gasometer.

As will be seen, the process is entirely continuous, each current of air following the same direction in the apparatus (from left to right, or right to left) that the current of steam did which preceded it, while each current of steam follows a direction opposite that of the current of air which preceded it.

The inventor estimates that the cost of the coal necessary for his process will not exceed a tenth of a cent per cubic foot of gas.

One important advantage of the apparatus is that it can be made of any dimensions. Instead of giving the generator the limited size and form shown in the engraving, with doors at the bottom for the removal of the ashes by hand from time to time, it may be constructed after the general model of the shaft of blast furnaces, with a hearth at the base. Upon adding to the fuel a small quantity of flux, all the mineral parts thereof can be melted into a liquid slag, which may be carried off just like that of blast furnaces. There is no difficulty in constructing regenerators of refractory bricks of sufficient capacity, however large the generators be; and a single apparatus might, if need be, convert one thousand tons of anthracite per day into more than five million cubic feet of gas.

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LIGHTING AND VENTILATING BY GAS.

[Footnote: A paper read before the Gas Institute, Manchester, June, 1885.]

By WILLIAM SUGG, of London.

Ever since the introduction of electric lighting, the public have been assured, by those interested in the different kinds of lamps—arc, glow or otherwise—that henceforth, by means of such lamps, rooms are to be lighted without heat or baneful products such as they assert attend the use of gas, lamps, or candles. But I think it must not be implied, from what any one has said in favor of the electric light as a means of lighting our dwellings, that gas is unsuitable for the purpose, or that the glow lamp is a perfect substitute for gas, or that there is a very large difference throughout the year on the points of health, convenience, or comfort, or that the balance in favor rests with electric light upon all or any of these points. The fact is, the glow lamp is only one more means (not without certain disadvantages) of producing light added to those which already exist, and of which the public have the choice. Now, looking to best means of lighting rooms, and particularly the principal rooms of a small dwelling-house, I beg to say that the arguments which can be adduced in favor of gas lighting in preference to any other means greatly preponderate, and that it can be substantiated that, light for light, under the heads of convenience, health, comfort, reliability, readiness, and cheapness, gas is superior to all.

As a scientific means for the purposes mentioned, gas is comparatively untried. This assertion may sound somewhat astounding; but I think it is a true one. More than that, even in the crude and unscientific way in which it has most frequently been used up to the present, it has been far from unsuccessful in comparison with electricity or other means of lighting; and in the future it will prove the best and cheapest practical means, although, for effect, glow lamps may be used in palatial dwellings in conjunction with it.

It must be remembered that, in laying down a system of artificial lighting, we have to imitate, as well as we can, that most beautiful and perfect natural light which, without our aid, and without even a thought from us, shines regularly every day upon all, in such an immense volume, so perfectly diffused, and in such wonderful chemical combination, that it may safely be said that not one atom of the whole economy of Nature is unaffected by it, and that we and all the animal kingdom, in common with trees and plants, derive health and vigor therefrom. This glorious natural light leaves our best gas, electricity, oil lamp, and all our multiplicity of candles, immeasurably behind. But although we cannot hope to equal, in all its beneficent results, the effects of daylight, or to perfectly replace it, we can more perfectly make the lighting of our homes comfortable (and as little destructive to the eyes and to the general health) by the aid of gas than by any other means. It must also be borne in mind that, in this country at least, we have to fulfill the conditions of artificial lighting under frequent differences of temperature and barometric influence, exaggerated by the manner in which our homes are built; and that for at least nine months of the year we require heat as well as light in our dwellings, and that for the other three months (excepting in some few favored localities) the nights are often chilly, even though the days may be hot. Therefore, independently of any effect produced by the lighting arrangements, there must be widely different effects produced in the temperature and conditions of the air in rooms by influences entirely beyond our control.

As an example of what I mean, a short time ago I had to preside over a meeting which was held in a large room—one of two built exactly alike, and in communication with each other by means of folding doors. These rooms formed part of one of the best hotels in London—let us call it the "Magnificent." Of course, it was lighted by electric glow lamps, in accordance with the latest fashion in that department of artificial lighting, viz., suspension lamps, in which the glow lamps grew out of leaves and scrolls, twisted and twirled in and out, very much after the pattern of our most aesthetic gas lamps, which, of course, are in the style of the most artistic (late eighteenth century) oil lamps, which were in imitation of the most classic Roman lamps, which followed the Persian, and so on back to the time of Tubal Cain, the great arch-artificer in metals, who most likely copied in metal some lamps he had seen in shells or flints. Both rooms were heated by means of the good old blazing coal fire so dear to a Briton's heart; and they were ventilated with all due regard to the latest state of knowledge on the subject among architects and builders. In fact, no pains had been spared to make these rooms comfortable in the highest acceptation of the word.

There were, some of our members remarked, no gas burners to heat and deteriorate the atmosphere, or to blacken the ceilings; and therefore, under the brilliant sparkle of glow lamps, the summit of such human felicity as is expected by a body of eighteen or twenty business men, intent on dispatching business and restoring the lost tissue by means of a nice little dinner afterward, ought, according to the calculations of the architect of the building, to have been reached. I instance this case because it is a typical one, which, under most aspects, does not materially differ from the conditions of home life in such residences as those whose occupiers are likely to use electric lighting. The rooms were spacious (about 20 feet by 35 feet, and about 15 feet high); and they were lighted during the day by means of large lantern ceiling-lights, with double glass windows. The evening in question was chilly, not to say cold.

Upon commencing our business, we all admired the comfort of the room; but as time went on, most of the company began to complain of a little draught on the head and back of the neck. The draught, which at first was only a suspicion, became a certainty, and in another hour or so, by the time our business was over, notwithstanding a screen placed before the door, and a blazing fire, we were delighted to make a change to the comfortable dining-room, which communicated with the room we had just left by means of folding doors, closed with the exception of just sufficient space left at one end of the room to allow a waiter to pass in and out. Very curiously, before the soup was finished, we became aware that the candles which assisted the electric glow lamps (merely for artistic effect) began to flare in a most uncandlelike manner—the flames turning down, as if some one were blowing downward on the wicks; and at the same time the complaints of "Draughts, horrid draughts!" became general, and from every quarter. Finding that, as the dinner went on, the discomfort became unbearable, even although the doors were shut and screens put before them, I gave up dining, and took to scientific discovery. The result of a few moments' observation induced me to order "those gas jets," which I saw peeping out from among the foliage of the electroliers, to be lighted up. In two or three minutes the flames of the candles burned upright and steadily, and in less than ten minutes the draughts were no longer felt; in fact, the room became really comfortable.

The reason of the change was simple. The stratum of air lying up at the ceiling was comparatively cold. The column of heated air from the bodies of the twenty guests, joined to the heat produced by the movements of themselves and the waiters, together with the steam from the viands and respiration, displaced the colder air at the ceiling, and notably that coldest air lying against the surface of the glass. This cold air simply dropped straight down, after the manner of a douche, on candles and heads below. The remedy I advised was the setting up of a current of hotter steam and air from the gas burners, which stopped the cooling effect of the glass, and created a stratum of heated steam and air in slow movement all over the ceiling. The effect was a comfortable sensation of warmth and entire absence of draught all round the table. Later on, to avoid the possibility of overheating the room, the gas was put out, and the electric lights left to themselves. But before we left, the chilliness and draughts began to be again felt.

The incident here narrated occurred at the end of the month of April last, when we might reasonably have hoped to have tolerably warm nights. It is therefore clear that in this instance neither electricity nor candles could effectually replace gas for lighting purposes. They both did the lighting, but they utterly failed to keep the currents of air steady. I have always remarked draughts whenever I have remained any length of time in rooms where the electric light is used. On a warm evening the electric light and candles would undoubtedly have kept the room cooler than gas, with the same kind of ventilation; I do not think they would have put an end to cold draughts. This the steam from the gas does in all fairly built rooms.

It is a well-known fact that dry air parts with its relatively small amount of specific heat, in an almost incredibly rapid manner, to anything against which it impinges. Steam, on the contrary, from its great specific heat, remains in a heated state for a much longer time than air. It is not so suddenly reduced to a low temperature, and in parting with its own heat it communicates a considerable amount of warmth to those bodies with which it comes in contact. Thus the products of the combustion of gas (which are principally steam) serve a useful purpose in lighting, by keeping at the ceiling level a certain stratum of heated vapor, which holds up, as it were, the carbonic acid and exhalation from the lungs given off by those using the room. The obvious inference, therefore, is that if we take off these products from the level of the ceiling, we shall take off at the same time the impure and vitiated air. On the other hand, if we make use of a system of artificial lighting, which does not produce any steam, then we shall have to adopt means to keep the air at the ceiling level warm, in order to prevent the heated impure air from descending in comparatively rapid currents, after having parted with its heat to the ceiling. It may very frequently be observed on chilly days that a number of currents of cold air seem to travel about our rooms, although there may be no crevices in the doors and windows sufficient to account for them; and, further, that these currents of cold air are not noticed when the curtains are drawn and the gas is lighted. The reason is that there is generally not enough heat at the ceiling level in a room unlighted with gas to keep these currents steady. Hence the complaints of chilliness which we constantly hear when electric lights are used for the illumination of public buildings. For example, at the annual dinner of the Institution of Civil Engineers, held at the end of April last in the Conservatory of the Horticultural Gardens, the heat from the five hundred guests, and from an almost equal number of waiters and attendants, displaced the cold air from the dome of the roof, and literally poured down on the assembly (who were in evening dress) in a manner to compel many of them to put on overcoats. If the Conservatory had been lighted with gas suspended below the roof, this would not have been the case, because sufficient steam would have been generated to stop these cold douches, and keep them up in the roof. In fact, if electric lights are to be used in such a building, it will be necessary to lay hot-water pipes in the roof, to keep warm the upper as well as the lower stratum of air, and thus steady the currents.

Having pointed out difficulties which arise under certain conditions of the atmosphere in rooms built with care, to make them comfortable when electric lighting is substituted for gas, I will lay before you some few particulars relative to the condition of small rooms of about 12 ft. by 15 ft. by 10 ft., or any ordinary room such as may be found in the usual run of houses in this country. The cubical contents of such a room equals 1,700 cubic feet. If the room is heated by means of a coal fire, we shall for the greatest part of the year have a quantity of air taken out of it at about 2 feet from the floor by the chimney draught, varying (according to atmospheric conditions and the state of the fire) from 600 to 2,000 or more cubic feet. This quantity of air must, therefore, be admitted by some means or other into the room, or the chimney will, in ordinary parlance, "smoke;" that is, the products of combustion, very largely diluted with fresh air, will not all find their way up the flue with sufficient velocity to overcome the pressure of the heavy cold air at the top of the chimney. If no proper inlets for air are made, this supply to the fire must be kept up from the crevices of the doors and windows. In the line of these currents of cold air, or "draughts" as they are usually called, it is impossible to experience any comfort—quite the contrary; and colds, rheumatism, and many other serious maladies are brought on through this abundant supply of fresh air in the wrong way and place.

According to General Morin (one of the best authorities on ventilation), 300 cubic feet of air per hour are required for every adult person in ordinary living rooms. Peclet says 250 cubic feet are sufficient; less than this renders the atmosphere stuffy and unhealthy. It is generally admitted that an average adult breathes out from 20 to 30 cubic inches of steam and vitiated air per minute, or, as Dr. Arnott says, a quantity equal in bulk to that of a full-sized orange. This vitiated air and steam is respired at a temperature of 90 deg. Fahr.; and therefore, by reason of this heat, it immediately ascends to the ceiling, together with the heat and carbonic acid given off from the pores of the skin. This fact, by the bye, can be clearly demonstrated by placing a person in the direct rays from a powerful limelight or electric lamp, and thus projecting his shadow sharply on a smooth white surface. It will be observed that from every hair of the head and beard, and every fiber of his clothing, a current of heated air in rapid movement is passing upward toward the ceiling. These currents appear as white lines on the surface of the wall; the cause probably being that the extreme rarefaction of the air by the heat of the body enables the rays of light to pass through them with less refraction than through the denser and more moist surrounding cold air. An adult makes, on an average, about 15 respirations per minute, and therefore he in every hour renders to the atmosphere of the room in which he is staying from 10 to 15 cubic feet of poisonous air. This rises to the ceiling line, if it is not prevented; and thus vitiates from 100 to 150 cubic feet of air to the extent of 1 per cent, in an hour. General Morin thought that air was not good which contained more than 1/2 per cent, of air which had been exhaled from the lungs; and when we consider how dangerous to health these exhalations are, we must admit that he was right in his view. Therefore in one hour the 15 foot by 12 foot room is vitiated to more than 2 feet from the ceiling by one person to the extent of 1/2 per cent., and it will be vitiated by two persons to the extent of 1 per cent, in the same time.

It must be remembered here that the degree of diffusion of the vitiated air into the lower fresh air contained in the remaining 8 feet of the height of the room depends very materially on the difference of temperature between these upper and lower strata and the movements of air in the room. The heavy poisonous vapors and gases fall into and diffuse themselves among the fresh air of the lower strata—very readily if they are nearly the same temperature as the upper, but scarcely at all if the air at the ceiling line is much hotter. Hence it occurs that, in warmed rooms of such size as I have mentioned, where one or two petroleum lamps are used for lighting them, after two or three hours of occupation by a family of three or four persons in winter weather, the air at the ceiling line has become so poisonous that a bird dies if allowed to breathe it for a very short time—sometimes, indeed, for only a few minutes. With candles, if the illumination of the room is maintained at the same degree as in the case of lamps, the contamination of the air is very much worse. It is doubtless the case that poisonous germs are rapidly developed in atmospheres which are called "stuffy;" and although, in a healthy state of the body, we are able to breathe them without perceptible harm, yet even then the slight headache and uneasiness we feel is a symptom which does not suffer itself to be lightly regarded, whenever, from some cause or other, the general condition is weak.

The products of combustion from coal gas (which are steam and carbonic acid mixed with an infinitesimal quantity of sulphur) are, proportionately, far less injurious to animal life than the products from an equal illuminating power derived from either oil or candles. They are, however, it is certain, destructive to germ life; and therefore, if taken off from the ceiling level, where they always collect if allowed to do so, no possible inconvenience or danger to health can be felt by any one in the room. But in our endeavors to take off the foul air at the ceiling, we encounter our first serious check in all schemes of ventilation. We draw the elevation and section of the room, and put in our flues with pretty little black arrows flying out of the outlets for vitiated air, and other pretty little red arrows flying in at the inlets; but when we see our scheme in practice, the black arrows will persist in putting their wings where their points ought to be; in other words, flying into instead of out of the room.

One of the best ways of finding the true course of all the hot and cold currents in a room is to make use of a small balloon, such as used to be employed for ascertaining the specific gravity of gases; and, having filled it with ordinary coal gas, balance it by weights tied on to the car till it will rest without going up or down in a part of the room where the air can be felt to be at about the mean temperature, and free from draught. Then leave it to itself, to go where it will.

As soon as it arrives in a current of heated air, it will ascend, passing along with the current, and descending or rising as the current is either warm or cold. The effect of the cold fresh air from windows or doors, as well as the effect of the radiant heat from the fire, can be thus thoroughly studied. Some of our pet theories may receive a cruel shock from this experiment; but, in the end, the ventilation of the room will doubtless be benefited, if we apply the information obtained. It will be discovered that the wide-throated chimney is the cause of the little black arrows turning their backs on the right path and our theoretical outlets for vitiated air becoming inlets. The chimney flue must have an enormous supply of air, and it simply draws it from the most easily accessible places. From 1,000 to 2,000 cubic feet of air per hour is a large "order" for a small room. Therefore, until we have made ample provision for the air supply to the fire, it is quite useless to attempt to ventilate the upper part of the room, either by ventilating gas lights or one of the cheap ventilators with little talc flappers, opening into the chimney when there is an up draught, and shutting themselves up when there is any tendency to down draught. The success of these and all other ventilators depends upon there being a good supply of air from under the door or through the spaces round the window frames. These fresh air supplies are, of course, unendurable; but if one of the spaces between the joists of the floor is utilized to serve as an air conduit, and made to discharge itself under the fender (raised about two inches for the purpose), quite another state of things will be set up. Then the supply of air thus arranged for will satisfy the fire, without drawing from the doors and windows, and at the same time supply a small quantity of fresh air into the room. But the important fact that the radiant heat from the fire will pass through the cold air without warming it all must not be lost sight of. In reality, radiant heat only warms the furniture and walls of the room or whatever intercepts its rays. The air of the room is warmed by passing over these more or less heated surfaces; and as it is warmed, it rises away to the ceiling. Therefore, if we desire to warm any of this fresh air supplied to the fire, it must be made to pass over a heated surface. The fender may be used for this purpose by filling up the two inch space along the front, as shown in the drawing, with coarse perforated metal. This will also prevent cinders from getting under it. It will be found that for the greater part of the year the chimney ventilator and the supply to the fire will materially prevent "stuffiness," and keep those disagreeable draughts under control, even although the room be lighted with a 3 light chandelier burning a large quantity of gas.



With improvements in gas burners, we may expect to light rooms perfectly with a less expenditure of gas than we now do. But we cannot light a room without in some measure creating heat; and I think I have shown that we want this heat at the ceiling line for the greater part of the year.

In summer we do not use gas for many hours; but, on the other hand, it is more difficult, with an outside temperature at 65 deg. to 70 deg. Fahr., to keep the air in proper movement in small rooms. There are also times in the fall of the year, and also in spring, when the nights are unusually warm; and, with a few friends in our rooms, the lighting becomes a "hot" question, not to say a "burning" one. On these occasions we have to resort to exceptional ventilation, which for ordinary every-day life would be too much. It is then, and on summer nights, that the system of ventilation by diffusion is most useful. To explain it, when two volumes of air of different temperatures or specific gravities find themselves on opposite sides of a screen or other medium, of muslin, cloth, or some more or less porous substance, they diffuse themselves through this medium with varying rapidity, until they become of equal density or temperature. Therefore, if we fill the upper part of a window (which can be opened, downward) with a strained piece of fine muslin or washed common calico, the air in the room, if hotter than the external air, will, when the window is more or less opened, pass out readily into the cooler air, and the cooler air will pass in through the pores of the medium. The hotter air passing out faster than the cooler air will come in, no draught will be experienced; and the window may be opened very widely without any discomfort from it.

It is, of course, quite impossible, in the limits of a paper, to do more than indicate a means of ventilation which will be effective under most circumstances of lighting with those gas burners and fittings usually employed, and which will lend itself readily to modifications which will be necessitated by the use of some of the newest forms of burners and ventilating gas lights.



In conclusion, I wish to draw attention to an important discovery I have made in reference to blackened ceilings, for which, up to the present time, gas has been chiefly blamed. I have long entertained the belief that with a proper burner it is possible to obtain perfect combustion, without any smoke; and a series of experiments with white porcelain plates hung over some burners used in my own house proved conclusively that the discoloration which spread itself all over my whitewashed ceilings arose from the state of the atmosphere, which in all large towns is largely mixed with heavy smoky particles, and from the dust or dirt created in rooms by the use of coal fires as well as from the smoke which, more frequently than one is at first supposed to imagine, escapes from the fire-place into the room. I therefore, in two of my best rooms, which required to have the ceilings whitened every year, substituted varnished paper ceilings (light oak paper, simply put on in the usual way, and varnished) instead of whitewash. I also changed the coal fires for gas fires. These alterations have gone through the test of two winters, and the ceilings are now as clean as when they were first done. The burners have been used every night, and the gas fires every day, during the two winters. No alteration has been made in the burners employed, and no "consumers" have been used over them. If the varnished paper ceilings are tried, I am sure that every one will like them better than the time honored dirty whitewash, which is simply a fine sieve. This fact is clearly shown by the appearance of the rafters, which, after a short time, invariably show themselves whiter than the spaces between.

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ANDERS' TELEPHONE.

Mr. G.L. Anders' telephone, shown in the accompanying cut, combines in a single apparatus a transmitter, A, a receiver, B, and a pile, C. The transmitter consists of a felt disk, a, containing several large apertures, and fixed by an insulating ring, c, to a metallic disk, d, situated within the box, D. The apertures, b, are filled with powdered carbon, e, and are covered by a thin metal plate, f, which is fixed to the insulating ring, c, by means of a metallic washer, g. Back of the transmitter is arranged the receiver, B, which consists of an ordinary electro-magnet with a disk in front of its poles. The pile, C, placed behind the receiver, consists of a piece of carbon, h, held by a partition, i, and covered with a salt of mercury, and of a plate of zinc, l, which is held at a distance from the mercurial salt by a spring, m, fixed to the insulating piece, n.



When the button, o, which is a poor conductor, is pressed, the zinc plate, l, comes into contact with the mercurial salt, and the circuit is closed through the line wire 1, the pile, the receiver, the transmitter, and the line wire 2, while when the button is freed the current no longer passes. The apparatus, then, can serve as a receiver or transmitter only when the button is pressed.—Bull. de la Musee de l'Industrie.

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BROWN'S ELECTRIC SPEED REGULATOR.

When the sea is rough, and the screw leaves the water as a consequence of the ship's motions, the rotary velocity of the screw and engine increases to a dangerous degree, because the resistance that the screw was meeting in the water suddenly disappears. When the screw enters the water again, the resistance makes itself abruptly felt, and causes powerful shocks, which put both the screw and engine in danger. Ordinary regulators are powerless to overcome this trouble, since their construction is such that they act upon the engine only when the excess of velocity has already been reached.

Several remedies have been proposed for this danger. For example, use has been made of a float placed in a channel at the side of the screw, and which closes the moderator valve by mechanical means or by electricity when the screw descends too low or rises too high.



Mr. Brown's system is based upon a new idea. The apparatus (see figure) consists of two contacts connected by an electric circuit. One of them, b, is fixed to the ship in such a way as to be constantly in the water, while the other, a, corresponds to the position above which the screw cannot rise without taking on a dangerous velocity. In the normal situation of the ship, the electric circuit, c (in which circulates a current produced by a dynamo, d), is closed through the intermedium of the water, which establishes a connection between the two contacts. When the contact, a, rises out of the water, the current is interrupted. The electro, d, then frees its armature, f, and the latter is pulled back by a spring—a motion that sets in action a small steam engine that closes the moderator valve. When the contact, a, is again immersed, the electro, e, attracts its armature, and thus brings the moderator valve back to its normal position. It is clear that the contact, a, must be insulated from the ship's side.

Several contacts, a, might be advantageously arranged one above another, in order to close the moderator valve more or less, according to the extent of the screw's rise or fall.

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MAGNETO-ELECTRIC CROSSING SIGNAL.

We illustrate to-day a new application of electricity to railroad crossing signaling which the Pennsylvania Steel Company, of Steelton, Pa., has just perfected. By its operation an isolated highway crossing in the woods or any lonely place can be made perfectly safe, and that, too, without the expense of gates and a man to work them or of a flagman. It is surely a great improvement over the old methods, and it is likely to have a large sale. In addition to considerations of safety, possible saving in salaries to railroad companies by its use will be great. This device is more reliable than a human being, and can make any crossing safe to which it is applied. Its operation is described as follows:



The illustration shows the device as used on a single track railroad, where it is so arranged as to be operated only by trains approaching the crossing (i.e., in the form illustrated, from the right). A similar box on the other side of the crossing is used for trains approaching in the other direction. Two plates connected by a link, and pivoted, are placed alongside of one rail, close enough to it to be depressed by the treads of the wheels. By another link, one of the plates called the rock plate (the one to the right) is connected to a rock shaft which extends through a strong bearing into the heavy iron case or box shown, at a suitable distance from the rail, within which an electric generator is placed; the whole being mounted and secured upon the ends of two long ties framed to receive it.

The action of this rock plate is peculiar. It is pivoted at the rear end, not to a fixed point, but to a short crank arm, the bearing for which is inclosed in the small box shown. As the first wheel of a train which is approaching in the desired direction (from the right in the engraving) touches it, it will be seen that it must not only depress it, but produce a slight forward motion, causing a corresponding rotary motion in the rock shaft which actuates the apparatus. On the other hand, when a train is approaching from the other direction, or has already passed the crossing, its wheels strike first the curved plate to the left of the illustration, and by means of the peculiar link connections shown, depress the rock plate so as to clear the wheels before the wheels touch it, but the depression is directly vertical, so that it does not give any horizontal motion to it, which would have the effect of actuating the rock shaft. Consequently, trains pass over the apparatus in one direction without having any effect upon it whatever, the different point at which the same force is applied to the rock plate giving the latter an entirely different motion.



The slight rotary motion which is in this way communicated to the rock shaft, when a train is approaching in the right direction, compresses a spring inside the case. As each wheel passes off the rock plate, the reaction of the spring throws it up again to its former position, giving additional speed to the gearing within, which is set in motion at the passage of the first wheel, and operates the electric "generator." The spring is really the motive power of the alarm. A small but heavy fly-wheel is connected with the apparatus, the top of which is just visible in the engraving, which serves to store up power to run the "generator," which is nothing more than a small dynamo, for the necessary number of seconds after the rear of the train has passed. The dynamo dispenses with all need for batteries, and reduces the work of maintenance to occasionally refilling the oil-cups and noticing if any part has been broken.

A suitable wire circuit is provided, commencing at the generator with insulated and protected wire, and continued with ordinary telegraph wire, which can be strung on telegraph poles or trees leading to the electric gong, Fig. 2, which rings as long as the armature revolves. It is a simple matter so to proportion the mechanism for the required distance and speed that the revolutions of the armature and the ringing of the gong shall continue until the train reaches the crossing; and as each wheel acts upon the apparatus, the more wheels there are in the train the longer the bell will ring, a very convenient property, since the slowest trains have nearly always the most wheels. The practical limits to the ringing of the gong are that it will stop sounding after the head of the train has passed the crossing and before or very soon after the rear has passed. A "wild" engine running very slowly might not actuate the signal as long as was desirable, but even then it is not unreasonably claimed the warning would probably last long enough for all practical requirements, as a team approaching a crossing at eight miles per hour takes 42 seconds to go 500 feet. All the bearings of any importance are self-lubricated by oil cups, the whole apparatus being designed to require inspection not more than once a month. The iron case when shut is water-tight, and when duly locked cannot be maliciously tampered with without breaking open the case; so that, the manufacturers claim, it will not be essential to examine it more than once a month. The parts outside the case are all strong and heavy, and not likely to get out of order, while easily inspected.

The apparatus can be used for announcing trains as well as sounding alarms, as the gongs can be placed upon any post or building. The gong has a heavy striker, and makes a great deal of noise, so that no one should fail to hear it.—Railway Review.

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THE SIZES OF BLOOD CORPUSCLES.

Professor Theodore G. Wormley, in the new edition of his work, gives the following sizes of blood corpuscles, as measured by himself and Professor Gulliver. We have only copied the sizes for mammals and birds. It will be seen that, with three or four exceptions, the sizes obtained by the two observers are practically the same:

Mammals Wormley. Gulliver.

Man 1-3250 1-3260 Monkey 1-3382 1-3412 Opossum 1-3145 1-3557 Guinea pig 1-3223 1-3538 Kangaroo 1-3410 1-3440 Muskrat 1-3282 1-3550 Dog 1-3561 1-3532 Rabbit 1-3653 1-3607 Rat 1-3652 1-3754 Mouse 1-3743 1-3814 Pig 1-4268 1-4230 Ox 1-4219 1-4267 Horse 1-4243 1-4600 Cat 1-4372 1-4404 Elk 1-4384 1-3938 Buffalo 1-4351 1-4586 Wolf (prairie) 1-3422 1-3600 Bear (black) 1-3656 1-3693 Hyena 1-3644 1-3735 Squirrel (red) 1-4140 1-4000 Raccoon 1-4084 1-3950 Elephant 1-2738 1-2745 Leopard 1-4390 1-4319 Hippopotamus 1-3560 1-3429 Rhinoceros 1-3649 1-3765 Tapir 1-4175 1-4000 Lion 1-4143 1-4322 Ocelot 1-3885 1-4220 Mule 1-3760 Ass 1-3620 1-4000 Ground squirrel 1-4200 Bat 1-3966 1-4173 Sheep 1-4912 1-5300 Ibex 1-6445 Goat 1-6189 1-6366 Sloth 1-2865 Platypus (duck-billed) 1-3000 Whale 1-3099 Capybara 1-3164 1-3190 Seal 1-3281 Woodchuck 1-3484 Muskdeer 1-12325 Beaver 1-3325 Porcupine 1-3369 Llama, Long diam. 1-3201 1-3361 Short " 1-6408 1-6229 Camel, Long diam. 1-3331 1-3123 Short " 1-5280 1-5876

WORMLEY GULLIVER. Birds. Length. Breadth. Length. Breadth.

Chicken 1-2080 1-3483 1-2102 1-3466 Turkey 1-1894 1-3444 1-2045 1-3599 Duck 1-1955 1-3504 1-1937 1-3424 Pigeon 1-1892 1-3804 1-1973 1-3643 Goose 1836 1-3839 Quail 2347 1-3470 Dove 2005 1-3369 Sparrow 2140 1-3500 Owl 1736 1-4076

The subject of minute measurements was discussed in an interesting manner in an address before the Microscopical Section of the A.A.A.S. last year, an abstract of which was published in this journal, vol. v., p. 181.

The slight differences in size accurately given in this table are not always appreciable under modern amplification, but under a power of 1,150 diameters "corpuscles differing by the 1-100000 of an inch are readily discriminated." For the conclusions of Prof. Wormley as regards the possibility of identifying blood of different animals, the reader is referred to his book on Micro-Chemistry of Poisons.—Amer. Micro. Jour.

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THE ABSORPTION OF PETROLEUM OINTMENT AND LARD BY THE SKIN.

[Footnote: From the American Druggist.]

E. Joerss has investigated the question whether ointments made with vaseline or other petroleum ointments are really as difficult of resorption by the skin, or of yielding their medicinal ingredients to the latter, as has been asserted. In solving this question, he considered himself justified in drawing conclusions from the manner in which such compounds behaved toward dead animal membrane. If any kind of osmosis could take place, he argued, from ointments prepared with vaseline, etc., through dead membranes, such osmosis would most probably also take place through living membranes. At all events, the endosmotic or exosmotic action of the skin of a living body must necessarily play an important role in the absorption of medicinal agents; and, on the other hand, it is plain that fats, which render the living skin impermeable, necessarily also diminish or entirely neutralize its osmotic action. To test this, the author made the following experiments:

Bladder was tied over the necks of three wide-mouthed vials, with bottoms cut off, and each was filled with iodide of potassium ointment.

No. 1 contained an ointment made with lard.

No. 2, one made with unguentum paraffini (Germ. Pharm.), and

No. 3, one made with unguentum paraffini mixed with 3 per cent. of lard.

All three vials were then suspended in beakers filled with water. After standing twenty-four hours at the ordinary temperature, the contents of none of the beakers gave any iodine reaction. After having been placed into a warm temperature, between 25-37 deg. C., all three showed iodine reactions after three hours, Nos. 2 and 3 very strongly, No. 1 (with lard alone) very faintly.

The same experiment was now repeated, with the precaution that the bladder was previously washed completely free from chlorine. Each vial was suspended, at a temperature of 25-27 deg. C., in 50 grammes of distilled water. After three hours, the contents of No. 1 (containing the ointment made with lard) gave no iodine reaction; the contents of the other two, however, gave traces. After eight hours no further change had taken place. The temperature was now raised to 30-35 deg. C., and kept so for eight hours. All three beakers now gave a strong iodine reaction, 0.2 c.c. of normal silver solution being required for each 15 grammes of the contents of the beakers.

In addition to the iodide, some of the fatty base had osmosed through the membrane in each case.

The next experiment was made by substituting a piece of the skin (freed from chlorine by washing) of a freshly killed sheep for the bladder. The ointment in No. 3 in this case was made with 10 per cent. of lard. No reaction was obtained, at the ordinary temperature, after twelve hours, nor after eight more hours, at a temperature of 25-30 deg. C. After letting them stand for eight hours longer at 30-37 deg. C., a faint reaction was obtained in the case of the ointment made with unguentum paraffini; a still fainter with No. 3; but no reaction at all with No. 1 (that made with lard). None of the fats passed through by osmosis. After eight hours more, the iodine reaction was quite decisive in all cases, but no fat had passed through even now. On titrating 20 grammes of the contents of each beaker,

No. 1 required 0.5 c.c. of silver solution. No. 3 " 0.5 c.c. " No. 2 " 0.7 c.c. "

showing that the most iodine had osmosed in the case of the ointment made with unguentum paraffini (equivalent to vaseline).

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THE TAILS OF COMETS.

I.—If we throw a stone into the water, a wave will be produced that will extend in a circle. The size of this wave and the velocity with which it extends depend upon the size of the stone, that is to say, upon the intensity of the mechanical action that created it. The extent and depth of the water are likewise factors.

If we cause a cord to vibrate in the water, we shall obtain a succession of waves, the velocity and size of which will be derived from the cord's size and the intensity of its action. These waves, which are visible upon the surface, constitute what I shall call mechanical waves. But there will be created at the same time other waves, whose velocity of propagation will be much greater than that of the mechanical ones, and apparently independent of mechanical intensity. These are acoustic waves. Finally, there will doubtless be created optical waves, whose velocity will exceed that of the acoustic ones. That is to say, if a person fell into water from a great height, and all his senses were sufficiently acute, he would first perceive a luminous sensation when the first optical wave reached him, then he would perceive the sound produced, and later still he would feel, through a slight tremor, the mechanical wave.[1]

[Footnote 1: Certain persons, as well known, undergo an optical impression under the action of certain sounds.]



Under the action of the same mechanical energy there form, then, in a mass of fluid, waves that vary in nature, intensity, and velocity of propagation; and although but three modes appreciable to our senses have been cited, it does not follow that these are the only ones possible.

We may remark, again, that if we produce a single wave upon water, it will be propagated in a uniform motion, and will form in front of it successive waves whose velocity of propagation is accelerated.

This may explain why sounds perceived at great distances are briefer than at small ones. A detonation that gives a quick dead sound at a few yards is of much longer duration, and softer at a great distance.

The laws that govern the system of wave propagation are, then, very complex.



II.—If an obstacle be in the way of the waves, there will occur in each of them an alteration, a break, which it will carry along with it to a greater or less distance. This succession of alterations forms a trace behind the obstacle, and in opposition to the line of the centers. Finally, if the obstacle itself emits waves in space that are of less intensity then those which meet it, these little waves will extend in the wake of the large ones, and will form a trace of parabolic form situated upon the line of the centers.



III.—Let us admit, then, that the sun, through the peculiar energy that develops upon its surface or in its atmosphere, engenders in ethereal space successive waves of varying nature and intensity, as has been said above, and let us admit that its mechanical waves are traversed obliquely (Fig. 1) by any spherical body—by a comet, for example; then, under the excitation of the waves that it is traversing, and through its velocity, the comet will itself enter into action, and produce mechanical waves in its turn. As the trace produced in the solar waves consists of an agitation of the ether on such trace, it will become apparent, if we admit that every luminous effect is produced by an excitation—a setting of the ether in vibration. The mechanical waves engender of themselves, then, an emission of optical waves that render perceptible the alteration which they create in each other.

Let a be the position of the comet. The altered wave, a, will carry along the mark of such alteration in the direction a b, while at the same time extending transversely the waves emitted by the comet. During this time the comet will advance to a', and the wave will be altered in its turn, and carry such alteration in the direction, a' b'.

The succession of all these alterations will be found, then, upon a curve a'' d' d, whose first elements, on coming from the comet, will be upon the resultant of the comet's velocity, and of the propagation of the solar waves. Consequently, the slower the motion of the comet, with respect to the velocity of the solar waves, the closer will such resultant approach the line of centers, and the more rectilinear will appear the trace or tail of the comet.



IV.—If the comet have satellites, we shall see, according to the relative position of these, several tails appear, and these will seem to form at different epochs. If c and s be the positions of a comet and a satellite, it will be seen that if, while the comet is proceeding to c', the satellite, through its revolution around it, goes to s', the traces formed at c and s will be extended to d and d', and that we shall have two tails, c' d and s' d', which will be separated at d and d' and seem to be confounded toward c' s'.

V.—When the comet recedes from the sun, the same effect will occur—the tail will precede it, and will be so much the more in a line with the sun in proportion as the velocity of the solar waves exceeds that of the comet.

If we draw a complete diagram (Fig. 4), and admit that the alteration of the solar waves persists indefinitely, we shall see (supposing the phenomenon to begin at a) that when the comet is at a 1, the tail will and be at a 1 b; when it is a 2 the tail will be at a 2 b'; and when it is at a 4, the tail will have become an immense spiral, a 4 b'''. As in reality the trace is extinguished in space, we never see but the origin of it, which is the part of it that is constantly new—that is to say, the part represented in the spirals of Fig. 4.

The comet of 1843 crossed the perihelion with a velocity of 50 leagues per second; it would have only required the velocity of the solar waves' propagation to have been 500 leagues per second to have put the tail in a sensibly direct opposition with the sun.

Knowing the angle [gamma] (Fig. 5) that the tangent to the orbit makes with the sun at a given point, and the angle [delta] of the track upon such tangent, as well as the velocity v of the comet, we can deduce therefrom the velocity V of the solar waves by the simple expression: