Further information may be obtained by addressing the inventor, as above.

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CHIMNEY FLUES.

Messrs. W. H. Jackson & Co., of this city, whose long experience in treating refractory flues gives weight to their opinion, communicate to the American Architect the following useful information:

To secure a good draught the chimney should be of sufficient size, should be carried up above surrounding objects, should be as straight as possible throughout its length, and should be as smooth as possible inside, to avoid friction. As a draught is caused by unequal temperatures, the chimney should be so arranged as to avoid a rapid radiation of heat. If in an exterior wall there should be at least 8 inches of brickwork between the flue and the exterior surface. For country houses it is much better to have the chimneys run up through the interior, as the flue is more easily kept warm, and the heat that is radiated helps to warm the house. The most frequent cause of a "smoky chimney" is the insufficient size of the flue for the grate or fireplace connected therewith. The flue should not be less than one eighth the capacity of the square of the width and height of the grate or fireplace. That is, if the grate has a front opening 20 inches wide and 26 inches high, the flue should be 8 in. x 8 in.; or, with an opening 36 inches wide and 32 inches high, the flue should be 12 in. x 12 in.; and, to get the best result, the opening into the flue from the grate or fireplace should be of a less number of square inches than the square of the flue, and never larger, as no more air should be admitted at the inlet than can be carried through the flue. Where there is more than one inlet to the same flue, the sum of all the inlets should not more than equal the size of the flue. A number of stoves may be connected with the same flue, one above another, if this rule is observed.

A square flue is better than a narrow one, as in two flues containing the same number of square inches the square flue would have the smallest amount of wall surface, and consequently less friction for the ascending currents, and less absorption of heat by the walls. Chimneys should be closely built, having no cracks nor openings through which external air may be drawn to weaken the draught. If they could be made throughout their length as impervious to air as a tube of glass, with interior surface as smooth, one cause of smoky chimneys would be removed. A downward current of air is frequently caused by some contiguous object higher than the chimney, against which the wind strikes. This higher object may sometimes be quite a distance from the chimney, and still affect it badly. A good chimney top constructed to prevent a down draught will remedy this difficulty. Each grate or fireplace should have a flue to itself. Under very favorable conditions, two grates or fireplaces might be connected with the same flue, but it is not a good plan. We have known grates and fireplaces connected with two flues, where they have been built under a window for instance, and, owing to there being insufficient room for a flue of suitable size, a flue has been run up on each side of the window. This is a very bad plan, and never can work well; it requires too much heat to warm both flues, and if the room in which the grate or fireplace is situated should be pretty close, so that there was no other entrance for air, there is danger that it would circulate down one flue and up the other, forcing smoke out of the fireplace into the room.

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IMPROVED FURNACE FOR BURNING GARBAGE.

The refuse matter and garbage of large cities is in the main composed of animal and vegetable offal of the kitchens; of the sweepings of warehouses, manufactories, saloons, groceries, public and private houses; of straw, sawdust, old bedding, tobacco stems, ashes, old boots, shoes, tin cans, bottles, rags, and feathers; dead cats, dogs, and other small animals; of the dust and sweepings of the streets, the condemned fruit, vegetables, meat, and fish of the markets, all of which compose a mass of the most obnoxious and unhealthy matter that can be deposited near human habitations.

The inventor of the furnace shown in the accompanying engravings aims to produce a change of form and of chemical nature and a great reduction in bulk of all such refuse and garbage within the limits of the city where it accumulates, without screening, separating, preparing, or mixing, without the expense of using other fuel, without any offensive odors being generated in the operation, and to produce an entirely unobjectionable residuum or product that may be made useful.



As a rule organic matter largely preponderates in the refuse, being as high in some instances as 94 per cent. There is always more than enough to generate sufficient heat to fuse the earthy or inorganic portion, which is mainly composed of sand, clay, and the alkalies from the coal and vegetable ashes, etc.

By producing a high degree of heat in the combustion of the organic portion of the refuse with a forced blast or forced draught, the non-combustible elements are fused, and form a vitreous slag, which is entirely inodorous and unobjectionable, and which may be utilized for many purposes.

The upper section or cone of the consuming furnace is built of boiler iron, and lined with fire brick resting upon an iron plate, which is supported by iron columns.

The hearth is made of fire brick, and is in the form of an inverted cone, being smaller at the bottom and larger at the top, as shown in Fig. 2.

The sides of the hearth are perforated near the bottom with arches for the tuyeres or blast pipes, and also in front for the special blast pipe and the tapping hole. The top of the furnace is closed with an iron plate, provided with a circular opening, through which the hopper enters the top of the furnace.

At the left in the larger engraving is seen an elevator, operated by a steam engine, for conveying the garbage and refuse to a platform, whence it is projected into the furnace by an inclined plane or chute.

Gas or smoke conductors convey the gas from the top of the furnace to the furnace of the boiler and to the heating oven, where it is used in heating air, which is conveyed through the iron pipes passing through the heating oven into a wind box, from which it enters the furnace at several points near the bottom by means of the tuyere pipes.



The consumption of the garbage is effected near the bottom of the furnace, where the air is forced in, and is continued as long as the blast is applied, and while burning at the base it is continually sinking down at the top, so that it is necessary to keep filling all the time. The odoriferous gases and the hot products of such combustion are forced upward through the superimposed mass, and escape to the fires of the boiler and heating oven, and, being largely composed of carbonic oxide and the hydrocarbon gases distilled from the animal and vegetable offal of the garbage, are thoroughly consumed; and it is said that by this means not only are all the offensive odors destroyed, but the heat generated is utilized for making steam and heating the air used for blast.

The refuse in its descent through the high furnace is exposed to the drying action of the hot gases of distillation and the hot products of combustion, its temperature increasing in its descent the nearer it approaches the tuyeres, and becomes completely desiccated and combustible when it reaches the blast. The high heat in this way obtained by the combustion of the organic portion melts all of the inorganic portion, forming a vitreous slag or glass, which may be allowed to run continuously, or by closing the tap may be allowed to accumulate, and can be drawn off at intervals. If there is an adequate supply of clay and sand in the refuse to combine with the ashes, the slag will run hot and free. The combination of silex or alumina and an alkali in proper portions always yields a fusible, easy-running compound.

The molten slag, as it runs from the furnace, may be discharged into tanks of cold water, which will pulverize or granulate it, making it like fine sand, or as it pours over a runner, through which it flows, if struck with a forcible air or steam blast it will be spun into fine thread-like wool.

The furnace once lighted and started may be kept running day and night continuously for days, months, or years, if desired; but if it becomes necessary to stop at any time, the tuyere pipes may be removed and the holes all stopped with clay, so as to entirely shut off the supply of air, and it will then hold in fire for many days, and will be in readiness to start again at any time the pipes are replaced and the blast turned on.

This furnace is the invention of Mr. Henry R. Foote, of Stamford, Conn.

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AN ANCIENT GREEK VASE.

The vase shown in the accompanying engravings must not be classed with ordinary ceramic ware, as it is a veritable work of art. It is the celebrated cup of Arcesilaus, which is preserved in the collection of the library of Richelieu street after having figured in the Durand Museum. It was found at Vulsei, in Etruria. It was made by a potter of Cyrene, the capital of Cyrenaica, founded by Greeks from the island of Thera. It is remarkable that Cyrene, removed from the center of Grecian manufacture, should possess a manufactory of painted vases from which have come so many works of art. The traveler, Paul Lucas, discovered in the necropolis of Cyrene, in 1714, many antique vases, both in the tombs and in the soil. One of them is still preserved in the Museum at Leyden. The Arcesilaus, who is represented on this vase, is not the celebrated skeptical philosopher of that name; it is Arcesilaus, King of Cyrenaica, who was sung by Pindar, and who was vanquished in the Pythian games under the 80th Olympiad (458 years B.C.).

The height of this vase is 25 centimeters, its diameter 28 centimeters. The paste is very fine, of a pale red. It is entirely coated with a black groundwork, which has been generally re-covered with a yellowish white clay, baked on.

According to M. Brongniart, this piece has been subjected to the baking process at least two or three times, thus indicating that the ceramic art had made considerable progress in Cyrene even at that remote epoch.

The following description of this vase is given in the catalogue of the Durand Museum: The King Arcesilaus is seated under a pavilion upon the deck of a ship. His head is covered with a kind of hat with a large brim, and his hair hangs down upon his shoulders. He is clothed in a white tunic and embroidered cloak or mantle, and he carries a scepter in his left hand; under his seat is a leopard, and his right hand he holds toward a young man, who makes the same gesture, and he is weighing in a large scale assafoetida, which is being let down into the hold of the ship. We know that he deals with assafoetida because one of the personages (the one who lifts up his arm toward the beam of the scale) holds in his right hand something resembling that which is in the scale, and the Greek word traced near it signifies "that which prepares silphium." Assafoetida, the resinous matter of the silphium, is used largely by the Greeks in the preparation of their food. The Orientals to-day make frequent use of it and call it the delight of the gods; while in Europe, because of its repulsive odor, it has long been designated as stircus diaboli.



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SNOW-RAISED BREAD.

Somebody thinks he has discovered that snow, when incorporated with dough, performs the same office as baking powder or yeast. "I have this morning for breakfast," says a writer in the English Mechanic, "partaken of a snow-raised bread cake, made last evening as follows: The cake when baked weighed about three quarters of a pound. A large tablespoonful of fine, dry, clean snow was intimately stirred with a spoon into the dry flour, and to this was added a tablespoonful of caraways and a little butter and salt. Then sufficient cold water was added to make the dough of the proper usual consistence (simply stirred with the spoon, not kneaded by the warm hands), and it was immediately put into a quick oven and baked three quarters of an hour. It turned out both light and palatable. The reason," adds the writer, "appears to be this: the light mass of interlaced snow crystals hold imprisoned a large quantity of condensed atmospheric air, which, when the snow is warmed by thawing very rapidly in the dough, expands enormously and acts the part of the carbonic acid gas in either baking powder or yeast. I take the precise action to be, then, not due in any way to the snow itself, but simply to the expansion of the fixed air lodged between the interstices of the snow crystals by application of heat. This theory, if carefully followed out, may perchance give a clew to a simple and perfectly innocuous method of raising bread and pastry." And stop the discussion as to whether alum in baking powders is deleterious to health or otherwise.

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NEW AGRICULTURAL INVENTIONS.

An improved gate, invented by Messrs. P. W. McKinley and George L. Ellis, of Ripley, O., is designed for general use. It is operated by cords and pulleys, and can be opened without dismounting from the horse. It is constructed so that it cannot sag, and is not liable to get out of order.

An improved apparatus for pressing tobacco has been patented by Mr. F. B. Deane, of Lynchburg, Va. It consists mainly in the construction of a suspended jack, arranged to travel over a row of hogsheads, so that a single jack gives successively to each hogshead the desired pressure.

An improved combined harrow and corn planter has been patented by Mr. M. McNitt, of Hanover, Kan. In this machine the opening, pulverizing, planting, and covering teeth are combined with a single frame.

A machine, which is adapted to the thrashing and cleaning of peas and seeds, and for cleaning all kinds of grain, has been patented by Mr. J. J. Sweatt, of Conyersville, Tenn.

Mr. Amos M. Gooch, of Farmington, W. Va., has patented an improved corn planter, which drops the fertilizer simultaneously with the seed, and is provided with a device for pressing the soil around the seed, leaving over the seed a portion of loose earth.

An improved machine for harvesting cotton has been patented by R. H. Pirtle, of Lowe's, Ky. This machine carries two vertical cylinders armed with teeth or spurs, and two inclined endless belts provided with teeth. The teeth of the cylinders and the belts remove the cotton from the plants, and deliver it to a receptacle carried by the machine.

Messrs. Julius Fern and Samuel Bligh, of Oneonta, N. Y., have patented an improved power for churning and other purposes where little power is required. It consists in the combination of a drum and weight, a train of gearing, and a pallet wheel arranged to oscillate a balanced beam.

An improvement in the class of feed cutters in which two or more knives work between parallel bars attached to the cutter box, has been patented by Messrs. J. N. Tatum and R. C. Harvey, of Danville, Va. The improvement consists in arranging the knives so that one begins and finishes its cut in advance of the other.

Mr. William Bradberry, of Darrtown, O., has invented an improvement in reciprocating churns. The aim of this inventor is to utilize the resistance of the milk as a source of power. To accomplish this a peculiar combination of mechanism is required, which cannot be clearly described without an engraving.

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READING AND EYESIGHT.

M. Javel, in a recent lecture, tries to answer the question, "Why is reading a specially fatiguing exercise?" and also suggests some remedies for this fatigue. First, M. Javel says reading requires an absolutely permanent application of eyesight, resulting in a permanent tension of the organ, which may be measured by the amount of fatigue or by the production of permanent myopy. Secondly, books are printed in black on a white ground; the eye is thus in presence of the most absolute contrast which can be imagined. The third peculiarity lies in the arrangement of the characters in horizontal lines, over which we run our eyes. If we maintain during reading a perfect immobility of the book and the head, the printed lines are applied successively to the same parts of the retina, while the interspaces, more bright, also affect certain regions of the retina, always the same. There must result from this a fatigue analogous to that which we experience when we make experiments in "accidental images," and physicists will admit that there is nothing more disastrous for the sight than the prolonged contemplation of these images. Lastly, and most important of all in M. Javel's estimation, is the continual variation of the distance of the eye from the point of fixation on the book. A simple calculation demonstrates that the accommodation of the eye to the page undergoes a distinct variation in proportion as the eye passes from the beginning to the end of each line, and that this variation is all the greater in proportion to the nearness of the book to the eye and the length of the line. As to the rules which M. Javel inculcates in order that the injurious effects of reading may be avoided, with reference to the permanent application of the eyes, he counsels to avoid excess, to take notes in reading, to stop in order to reflect or even to roll a cigarette; but not to go on reading for hours on end without stopping. As to the contrast between the white of the paper and the black of the characters, various experiments have been made in the introduction of colored papers. M. Javel advises the adoption of a slightly yellow tint. But the nature of the yellow to be used is not a matter of indifference; he would desire a yellow resulting from the absence of the blue rays, analogous to that of paper made from a wood paste, and which is often mistakenly corrected by the addition of an ultramarine blue, which produces gray and not white. M. Javel has been led to this conclusion both from practical observation and also theoretically from the relation which must exist between the two eyes and the colors of the spectrum. His third advice is to give preference to small volumes which can be held in the hand, which obviates the necessity of the book being kept fixed in one place, and the fatigue resulting from accidental images. Lastly, M. Javel advises the avoidance of too long lines, and therefore he prefers small volumes, and for the same reason those journals which are printed in narrow columns. Of course every one knows that it is exceedingly injurious to read with insufficient light, or to use too small print, and other common rules. M. Javel concludes by protesting against an invidious assertion which has recently been made "in a neighboring country," according to which the degree of civilization of a people is proportional to the number of the short sighted shown to exist by statistics; the extreme economy of light, the abuse of reading to the detriment of reflection and the observation of real facts, the employment of Gothic characters and of a too broad column for books and journals, are the conditions which, M. Javel believes, lead to myopy, especially if successive generations have been subjected to these injurious influences.

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PHOSPHORESCENCE.

M. Nuesch records, in a recent number of the Journal de Pharmacie, some curious observations regarding luminous bacteria in fresh meat. Some pork cutlets, he found, illuminated his kitchen so that he could read the time on his watch. The butcher who sent the meat told him the phosphorescence was first observed in a cellar, where he kept scraps for making sausages. By degrees all his meat became phosphorescent, and fresh meat from distant towns got into the same state. On scratching the surface or wiping it vigorously, the phosphorescence disappears for a time; and the butcher wiped carefully the meat he sent out. All parts of the animal, except the blood, acquired the phenomenon over their whole surface. The meat must be fresh; when it ceases to be so, the phosphorescence ceases, and Bacterium termo appear. None of the customers had been incommoded. It was remarked that if a small trace of the phosphorescent matter were put at any point on the flesh of cats, rabbits, etc., the phosphorescence gradually spread out from the center, and in three or four days covered the piece; it disappeared generally on the sixth or seventh day. Cooked meat did not present the phenomenon but it could be had in a weak manner, from cooked albumen or potatoes. No other butcher's shop in the place was affected. The author is uncertain whether to attribute the complete disappearance of the phenomenon to the higher temperature of the season, or to phenic acid, or to fumigation with chlorine.

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THE CHARMS OF NATURAL SCIENCE.

The Earl of Derby, in an address at the Edinburgh University, said: "Of the gains derivable from natural science I do not trust myself to speak; my personal knowledge is too limited, and the subject is too vast. But so much as this I can say—that those who have in them a real and deep love of scientific research, whatever their position in other respects, are so far at least among the happiest of mankind.... No passion is so absorbing, no labor is so assuredly its own reward (well that it is so, for other rewards are few); and they have the satisfaction of knowing that, while satisfying one of the deepest wants of their own natures, they are at the same time promoting in the most effectual manner the interests of mankind. Scientific discovery has this advantage over almost every other form of successful human efforts, that its results are certain, that they are permanent, that whatever benefits grow out of them are world-wide. Not many of us can hope to extend the range of knowledge in however minute a degree; but to know and to apply the knowledge that has been gained by others, to have an intelligent appreciation of what is going on around us, is in itself one of the highest and most enduring of pleasures."

THE VESUVIUS RAIL WAY.—The Italian Ministry of Public Works, in union with the Ministry of Finance and the Prefecture of Naples, has issued the concession for the construction of the Vesuvius Railway. The line will run along that part of the mountain which has been proved, after the experience of many years, to be the least exposed to the eruptions. The work is to be commenced immediately, and it is believed that it will come into use during the present year. A sufficient number of carriages are being built to convey 600 persons during the day. The line is to be constructed upon an iron bridge, built after a patented system.

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THE POTTERY TREE.

Among the various economic products of the vegetable kingdom, scarcely any hold a more important place than barks, whether for medicinal, manufacturing, or other purposes. The structure and formation of all barks are essentially very similar, being composed of cellular and fibrous tissue. The cell contents of these tissues, however, vary much in different plants; and, for this reason, we have fibrous or soft, woody, hard, and even stony barks. To explain everything which relates to the structure of bark would lead us into long details which our space will not permit. Briefly stated, the bark of trees (considering, now, those of our own climate) consists of three layers. The outermost, called the "cortical," is formed of cellular tissue, and differs widely in consistency in different species; thus, in the cork oak, which furnishes man with one of his most useful commercial products, the cortical layer acquires extraordinary thickness. The middle layer, called the "cellular" or "green bark," is a cellular mass of a very different nature. The cells of which it is composed are polyhedral, thicker, and more loosely joined, and filled with sap and chlorophyl. The inner layer (next the wood), called the "liber," consists of fibers more or less long and tenacious. It is from the liber that our most valuable commercial fibers are obtained. In some plants the fibrous system prevails throughout the inner bark; but what we wish to refer to more particularly at present is a remarkable example of the harder and more silicious barks, and which is to be found in the "Pottery Tree" of Para. This tree, known to the Spaniards as El Caouta, to the French as Bois de Fer, to the Brazilians as Caraipe, is the Moquilea utilis of botanists, and belongs to the natural order Ternstroeiaceae. It is very large, straight, and slender, reaching a height of 100 feet before branching; its diameter is from 12 to 15 inches; and its wood is exceedingly hard from containing much flinty matter. Although the wood of the tree is exceedingly sound and durable, the great value of the tree to the natives exists in the bark for a purpose which, to say the least, is a novel one in the application of barks—that of the manufacture of pottery. The Indians employed in the manufacture of pottery from this material always keep a stock of it on hand in their huts for the purpose of drying and seasoning it, as it then burns more freely, and the ashes can be gathered with more ease than when fresh. In the process of manufacturing the pottery the ashes of the bark are powdered and mixed with the purest clay that can be obtained from the beds of the rivers; this kind being preferred, as it takes up a larger quantity of the ash, and thus produces a stronger kind of ware. Though the proportions of ash and clay are varied at the will of the maker, and according to the quality of the bark, a superior kind of pottery is produced by a mixture of equal parts of fine clay and ashes. All sorts of vessels of small or large size for household or other purposes are made of this kind of ware, as are also vases or ornamental articles, many of which are painted and glazed. These articles are all very durable, and are able to stand almost any amount of heat; they are consequently much used by the natives for boiling eggs, heating milk, and indeed for culinary purposes generally. A brief glance at the structure of the bark will show how it comes to be so well adapted for this purpose. The bark seldom grows more than half an inch thick, and is covered with a skin or epidermis; when fresh, it cuts somewhat similar to a soft sandstone, but when dry, it is very brittle and flint like, and often difficult to break. On examination of a section under the microscope, all the cells of the different layers are seen to be more or less silicated, the silex forming in the cells when the bark is still very young. In the inner bark the flint is deposited in a very regular manner, the particles being straight and giving off branches at right angles; that of the porous cells of the bark, however, is very much contorted, and ramifies in all directions. In the best varieties of the tree, those growing in rich and dry soil, the silex can be readily detected by the naked eye; but to test the quality of the various kinds of bark, the natives burn it and then try its strength between their fingers; if it breaks easily it is considered of little value, but if it requires a mortar and pestle to break, its quality is pronounced good. From an analysis of this singular bark, that of old trees has been found to give 30.8 per cent of ash, and that of young 23.30 per cent. Of the different layers of old bark, the outer gave 17.15 per cent, the middle 37.7, and the inner 31. The wood of the tree, in comparison with the bark, is relatively poor in silex, the duramen of an old tree giving only 2.5 per cent of silex.

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GLASS SPONGES.

The natural history of sponges had, up to the middle of this century, been comparatively neglected. Until 1856, when Lieberkuhn published his treatise on sponges, very little or nothing had been written on the subject. Later, Haeckel did much to determine their exact nature, and it is now universally admitted that sponges form one of the connecting links between the animal and the vegetable kingdom.

Sponges, generally considered, consist of fine porous tissue, covered, during life, with viscid, semi-liquid protoplasm, and are held in shape and strengthened by a more or less rigid skeleton, consisting chiefly of lime or silica. The tissue consists of a very fine network of threads, formed probably by gradual solidification of the threads of protoplasm. The inorganic skeleton is formed by larger and smaller crystals and crystalline threads. In the various families of sponges the quantity of inorganic matter varies greatly; some sponges are nearly devoid of an inorganic skeleton, while other families consist chiefly of lime or silica, the organic tissue being only rudimentarily developed.

As observed in their natural state, sponges are apparently lifeless. When, however, a live sponge is placed in water containing some finely powdered pigment in suspension, it will be noticed that in regular, short intervals water is absorbed through the pores of the tissue and ejected again through larger openings, which are called "osculae." Following up these into the interior, we find them divided into numerous branches, the walls of which are, under the microscope, found to be covered with minute cells, fastened at one end only and oscillating continually. By means of these cells the sponge receives its nourishment.

Sponges with very rigid inorganic skeletons may be divided into two classes—calcareous and silicious—according to whether the skeleton is chiefly composed of lime or silica.

Our engravings represent two species of the latter kind, which are, on account of the peculiar appearance of their skeleton, called glass sponges.

Fig. 1 represents the "sprinkling pot sponge," Eucleptella aspergillum. It is generally found in very deep water throughout the Pacific. Specimens were found over fifty years ago, but, as they had to be brought up from depths between 500 and 800 fathoms, they remained very scarce and sold at fabulous prices.



The skeleton is formed by small crystals and long threads of vitreous silica, cemented together, during life, by protoplasm. They are arranged in longitudinal and annular bands so as to form a long curved cylinder, about nine to twelve inches long, the walls of which are about one inch in thickness. The threads and bands are interwoven with the greatest regularity, and when the skeleton is freed from the adhering organic matter, it looks extremely beautiful.

The mode in which the intersecting bunches of crystals are connected is shown in Fig. 2. The upper end of the cylinder is closed by a perforated cover, which probably has given rise to the name of the sponge. The upper portion of the cylinder is surrounded by a few irregular, annular masses of organic tissue, which adheres loosely only to the skeleton. The lower end is formed by a bunch of long threads, rooting firmly in the ground.



Up to about ten years ago the price of specimens of this sponge was very high. At that time, however, a colony of Eucleptellas was found near the cities of Cebu and Manila, in the East Indies, in a depth not exceeding 100 fathoms, and since they have appeared in larger quantities in the market. It is remarkable that, contrary to their habits, these organisms have immigrated into regions to which they were totally unaccustomed. Yet it must be regarded as a greater curiosity that they have been accompanied to their new abode by a few animals living in equally deep water and never met with before at depths less than three or four hundred fathoms. Among these animals is a Phormosoma (water hedgehog), noted for its long spines.

Glass sponges are not confined to tropical regions. They are met with in latitudes as high as the Faeroee Islands, where the beautiful Holtenia Carpentaria abounds. It is represented in Fig. 3. Its cup-shaped skeleton is similar in structure to that of the Eucleptella; numerous crystalline needles protrude from the surface of the upper part. Lately some specimens of Holtenia have been found on the coast of Florida.



Glass sponges serve as dwellings for numerous animals, especially crustaceae. A small shrimp inhabits the tubes of the Eucleptella, a male and a female generally living together. They are shut up as in a prison in their crystalline home, as they are generally too large to pass through the meshes formed by the bundles of crystals. It was formerly believed that these skeletons had actually been built by the shrimps, and we can find no explanation for this curious circumstance, other than that the shrimps entered these habitations while very small and became too large to leave them.

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PLANTS PROTECTED BY INSECTS.

Mr. Francis Darwin, in a lecture on "Means of Self-Defense among Plants," delivered lately at the London Institution, said that one of the most curious forms of defense known is afforded by a recently discovered class of plants, which, being stingless themselves, are protected by stinging ants, which make their home in the plant and defend it against its enemies. Of these the most remarkable is the bull's-horn acacia (described by the late Mr. Belt in his book "The Naturalist in Nicaragua"), a shrubby tree with gigantic curved thorns, from which its name is derived. These horns are hollow and tenanted by ants, which bore a hole in them, and the workers may be seen running about over the green leaves. If a branch is shaken the ants swarm out of the thorns and attack the aggressor with their stings. Their chief service to the plant consists in defending it against leaf-cutting ants, which are the great enemy of all vegetation in that part of America. The latter form large underground nests, and their work of destruction consists in gathering leaves, which they strip to form heaps of material, which become covered over with a delicate white fungus, on which the larvae of the ants are fed, so that literally they are a colony of mushroom growers. The special province of the little stinging ants, which live in the thorns of the acacia, is, therefore, to protect the leaves of the shrub from being used by the leaf-cutters to make mushroom beds. Certain varieties of the orange tree have leaves which are distasteful to the leaf-cutters, this property of the leaves thus forming a means of defense. Other plants are unaccountably spared by them—grass, for example, which, if brought to the nest, is at once thrown out by some ant in authority. The bull's-horn acacia, in return for the service rendered by the stinging ants, not only affords them shelter in its thorns, but provides them with nectar secreted by glands at the base of its leaves, and also grows for them small yellow pear-shaped bodies, about one twelfth of an inch in length, at the tip of some of its leaflets, which they use as food. These little yellow bodies are made up of cells containing protoplasm rich in oil, and afford the insects an excellent food. When the leaf unfolds, the ants may be seen running from one leaflet to another, to see if these little yellow bodies are ripe; and if they are ready to be gathered they are broken up by the ants and carried away to the nest in the thorn. Several small birds, also, build their nests in the bull's horn acacia, thus escaping from a predatory ant which is capable of killing young birds. The trumpet tree, another plant of South and Central America, is also protected by a standing army of ants; and, like the above mentioned acacia, grows for its protectors small food bodies containing oil, but instead of secreting nectar in its leaves it harbors a small insect (coccus), whose sweet secretion is much relished by the ants. Dr. Beccari mentions an epiphytal plant growing on trees in Borneo, the seeds of which germinate, like those of the mistletoe, on the branches of the tree; and the seedling stem, crowned by the cotyledons, grows to about an inch in length, remaining in that condition until a certain species of ant bites a hole in the stem, which then produces a gall-like growth that ultimately constitutes the home of the ants. If the plant is not fortunate enough to be bitten by an ant it dies. These ants, then, protect their plant home by rushing out fiercely on intruders, and thus are preserved the sessile white flowers which, in this plant, are developed on the tuber like body.

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ADVANCE IN IRON.—At a meeting of the Philadelphia Iron Merchants' Association, March 11, prices of all descriptions of merchant iron were advanced fully 5 per cent.

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THE ANEROID BAROMETER.

The aneroid barometer was invented by M. Vidi, of Paris. It consists essentially of a circular box, the face of which is made of thin elastic metal, rendered more elastic by being stamped and pressed into concentric circular wave-like corrugations. This box is nearly exhausted of air, and its elastic face supports the pressure of the atmosphere, and yields to it with elastic resistance in proportion to the amount of pressure. Thus, if the atmospheric pressure increases, the face is pressed inward; if atmospheric pressure diminishes, the elastic reaction of the metal moves the face outward. These movements are communicated to an index by suitable and very delicate mechanism, and registered in largely magnified dimensions, by the movements of this index upon the face of the dial.

Aneroid barometers are now made of pocket size, compensated for temperature, and with double scales, one reading the height of the barometer column, the other the elevation obtained. I have, says Prof. W. M. Williams, used one of these during many years, and find it a very interesting traveling companion. It is sufficiently sensitive to indicate the ascent from the ground floor to the upper rooms of a three-storied house, or to enable the traveler sitting in a railway train to tell, by watching its face, whether he is ascending or descending an incline.

Such slight variations are more easily observed on the aneroid than on the mercurial barometer, and therefore it is commonly stated that the aneroid is the more sensitive instrument. This, however, is a fallacious conclusion. It is not the superior sensitiveness of the movements of the instrument, but the greater facility of reading them, that gives this advantage to the aneroid, the index of which has a needle point traveling nearly in contact with the foot of the divisions; the readings are further aided by a needle point register attached to a movable rim, which may be brought point to point against the index, thus showing the slightest movement that human vision may detect. A magnifying lens may be easily used in such a case.

It should be understood that the aneroid barometer is not an independent instrument; it is merely a device for representing the movements of the mercurial barometer. It is regulated by comparison with the primary instrument, and this comparison should be renewed from time to time, as the elastic properties of the metal may and do vary.

An adjusting or regulating screw is attached to the back of the instrument, and is usually movable by a watch key.

Besides this, the magnified reading of course magnifies any primary error, and is largely dependent on the accuracy of the mechanism.

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THE ALBO-CARBON LIGHT.

We need hardly remind our readers that numerous unsuccessful attempts have been made at various times to enrich ordinary coal gas by the aid of volatile oils. Upon the present occasion we have to place before them particulars of a process having the same object in view, but which is so far dissimilar in that it deals with a solid substance instead of a liquid oil. The invention has been brought into its present practical shape by Mr. James Livesey, C. E., of No. 9 Victoria Chambers, Westminster, in conjunction with Mr. Kidd, with whom it originated. The process consists in the employment of a substance called albo-carbon, which is the solid residuum of creosote. This material is moulded into the form of candles, which in large lamps are placed in a metallic vessel or receiver near the gas burner. The albo-carbon is warmed by the heat of the burning gas, the heat being transmitted to the receiver by a metallic conductor. Upon the albo-carbon being raised to the necessary temperature it volatilizes, and as the coal gas passes over it to the burner its vapor becomes mingled with the gas, and greatly raises its illuminating power. Of course when first lighted the coal gas only is burned, but in a few minutes the albo-carbon communicates its enriching vapor to it. The only alteration necessary to the present gas fittings is the vaporizing chamber, which is of simple construction, although at present the details of the various arrangements necessary for the different kinds of lights have not yet been fully worked out. This invention is now being tried experimentally in the eastern section of the Westminster Aquarium, where we recently examined it, and found it to afford a marked improvement upon the ordinary system of gas illumination, although a smaller number of burners is being used. Tried alternately with ordinary coal gas, the higher illuminating power of the albo-carbon light was very remarkable. It appears that there are 200 burners fitted at the Aquarium with the new light, and these successfully take the place of 500 ordinary gas burners previously in use. The illuminating effect is stated to be doubled, with an additional advantage as regards economy. The reduction of cost arises from the smaller quantity of gas consumed with the albo-carbon process than without it, and the very small cost of the enriching material. According to our information, 1,000 cubic feet of ordinary gas as generally used will, by the albo-carbon appliance, give as much illumination as 3,000 cubic feet without it, and the cost of the material to produce this result is only 1s. 6d. Experiments have been made with this light by Mr. T. W. Keates, the consulting chemist to the Metropolitan Board of Works, who reports very favorably upon it, as does also Dr. Wallace, of Glasgow, who has obtained some very satisfactory results with it. It is claimed for the albo-carbon material that it is perfectly inexplosive, safe and portable, that it causes no obstruction and leaves no residuum, and that the receivers can be replenished almost indefinitely without any accumulation taking place, so perfect is the evaporation of the albo-carbon. On the whole the display at the Aquarium speaks greatly in favor of the new process of gas enrichment, which, other things being equal, bids fair to find its way into practice.—Engineering.

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ENGLISH AND AMERICAN HARDWARE.

Mr. Frederick Smith, Manager of the Union Land and Building Company (limited), recently read a paper on the above subject before the Manchester Scientific and Mechanical Society. Mr. H. Whiley, Superintendent of the Manchester Health Department, presided. The following is the text of the paper, as given in the London Ironmonger. The lecturer said:

A spectator in any of our courts of justice will generally be struck with the amount of hard swearing which is given to the court, under the name of evidence. He will find one set of witnesses testifying, under oath, to one thing, and another set, also under oath, to the very opposite. Some prove too much, some too little, some are of a totally negative character, proving nothing, and some are of no character at all, and therefore are willing to prove anything. To some extent the same phenomena are to be observed in reference to the question of foreign competition. On the one hand the manufacturers hold up to our affrighted vision the picture of our mills stopped, our machine shops standing empty and idle, our hardware trade slipping through our fingers, our ships rotting in our own and in foreign ports, and our greatness as a producing nation for ever passed away. On the other hand, the journalists who take the labor side of the question, the trades-union leaders, and a large number of the workmen themselves, hold that we have little or nothing to fear from our foreign rivals; that the depression, like those atmospheric ones of which our American cousins are constantly warning us, will pass away, and leave us with better times to follow. I will, therefore, as far as possible, keep out of the region of speculation, give you a few facts, show you some examples, and leave you to draw your own inferences. Some two or three years ago ordinary axle pulleys of English make were difficult to get; the price was scandalously high, and the quality as scandalously low. Out of a dozen probably four would not turn round without sticking, and the casting was—well, simply vile. I show you a sample rather above the average, and the retail price for this inferior article was 22s. per gross. All at once the Americans deluged the English market with the pulley which I now show to you, and it needs no explanation of mine to satisfy the mechanical minds present of the superiority of the transatlantic article; but when we also bear in mind that the price of the American was from 25 to 33 per cent less than the English pulley, you can understand how the builders exulted, and how the Volscians of the Birmingham district were fluttered. Then, and not till then, would the English maker condescend to believe that it was possible to improve upon the wretched things which he had foisted upon his customers, and he at once commenced to copy the American pulley. He has not yet succeeded in producing such a beautiful casting, but I venture to say that he has improved the quality more in the last eighteen months than in the previous eighteen years.

Now take the ordinary door furniture. For generations the English builder and householder has had to be content with the stereotyped, with all its aggravating propensities. First, the little screw (so small as to be scarcely perceptible to touch or to sight) shakes loose from its countersunk depression in the spindle, gets lost, and lets the knob go adrift; or next, the knob itself, formed of a bit of sheet brass, turns round on its shank and the door cannot be opened, or the shank, not having a sufficient bearing on the spindle, works loose, and the whole thing is out of repair. It is the same thing to-day as it was when it tormented my grandfather; for, of course, no improvement could be made until Uncle Sam sent us his cheap, strong, serviceable, and sensible "Mineral Knob."

The English maker says: "But look at the many devices which we have invented for door furniture." Granted, and some of them very good, but none of them so good as this—for the money. Plenty of them well adapted for extraordinary use, but none of them cheap enough and strong enough to be placed in competition with this in fitting up the dwelling of the ordinary Englishman. The spindle and furniture of a lock is the portion which is liable to and receives the most rough usage.

I have here an ordinary cheap set of china furniture of English make, which I dare not drop lest I should break it, but as you see, I dare throw its Yankee competitor the whole length of this room. The retail price of this English set is ninepence—the price of the American is less than sixpence. The English spindle is fitted with the usual little screw, the knob is loose, the roses are china, and liable to break with the least strain or blow. The American set, as you see, has a long shank; the form of the knob is a very oblate spheroid, giving a good grip and free play for the fingers between the knob and the door. The rose is japanned iron, and has small studs or teeth projecting on its inner side effectually preventing it from turning round with the spindle; the screw is strong, and is tapped through the spindle itself, insuring both security and perfect steadiness. Several small washers are supplied with each spindle, enabling the slack to be taken up perfectly, and at the same time preventing the spindle from sticking with any ordinary amount of friction.

I will now show you a cheap American rim lock. First, you will notice that both sides are alike. Next, that by pulling the latch forward it can be turned half round, and is thereby converted from a right hand to a left hand, or vice versa, in an instant. This is an important point to a builder, but our lockmakers do not seem to know it. Several attempts have been made to introduce locks of this kind, but the fancy prices put upon every article which departs, in ever so slight a measure, from the antediluvian patterns mostly used, practically prohibits their adoption. The carcass of the lock is of cast iron; the casting, like all the small American castings, is simply perfect; bosses are cast round the follower and keyholes; the box staple is one piece of metal, neat and strong.

But there is another point, and, to my mind, the most important one. Whatever opinions may be held as to the relative quality of this lock, whether it is better or worse than an English one, it is at least an honest article. It makes no pretensions to be any better than it is. It does not entrap the unwary purchaser by pretending to be a first-class article, when at the same time it may be a swindle.

I will now show you an ordinary 6 inch rim-lock of English manufacture. At a short distance it looks like a superior article; the follower and keyhole appear as if they were bushed with brass. But let us take it to pieces, and see what we can find. The follower is a rough casting, not turned at the bearings, and is in no sense a fit. The screw holes are not countersunk, but merely punched in; the key is of the roughest and worst fitting description; the inside is as rough and cheap as possible; the key is cut so as to deceive the purchaser into the belief that there are twice as many wards in the lock as is really the case, and the bushes prove to be thin plates of brass riveted on, and not bushes at all. In short, the whole article is a vile fraud, and the maker was a swindler. This is strong language, but I think you will agree with me when I maintain that it is not stronger than the circumstances warrant.

But there are still its defects of bad design and useless workmanship. The lock is of the usual form given to the English rim-lock, that is, it has a flange which requires to be let into the edge of the door. I have fixed hundreds of them, and have never yet been able to see a use for this flange. It is one great obstacle to the general introduction of a reversible lock; it adds to the labor of fixing without adding to the security of the door, for if the door is to be forced from the outside, the box staples give way first; if from the inside, the unscrewing of the box staple is all that is necessary to give egress; if the door requires easing, it effectually prevents it being done—in fact, it is a nuisance, and nothing but a nuisance. But our lockmakers do not appear to give these things a thought; their doctrine seems to be, "As it was in the beginning, is now, and ever shall be."

Again, notice that the edges of the iron which lie against the door and the sham bushes are ground bright. Here is labor wasted, for as soon as the lock is fixed these polished portions are hidden for ever. Next, take the box staple. As is usual, it is fearfully and wonderfully made up of sheet iron, square iron, and brass; the outcome of which is that the showy brass striking piece comes unriveted, the door comes unfastened, and the tenant's temper comes unhinged. Why, in the name of common sense, could they not substitute a neat malleable casting? In our own houses I have long since discarded the ordinary box staple for draw-back locks, and find it cheaper to buy a cast iron staple, and throw away the one supplied by the English lockmaker.

Bear in mind that I have shown neither of these locks as samples of high-class goods, but as samples of the furniture fixed in the houses of the working and middle classes of this country; and when I tell you that the American lock, fitted with the mineral furniture, is at least 25 per cent cheaper than the English abortion I have shown to you, you will begin to realize what our English markets have to fear from the Americans.

Here is a common, cheap English mortise lock, and you will naturally ask why the outside of this lock is ground bright, when it is buried in the door and never seen except it has to be taken out for repairs. I have asked the same question, and for 20 years have paused for a reply. This lock is not reversible, the follower is not bushed, and the inside is rough and cheap. Contrast it with this neat American lock, and notice again the bosses to receive the wear; notice also that the bolts are brass; the latch-bolt is, of course, reversible—I never saw an American lock which was not. The body of the lock is cast iron; and, seeing that there are no strains upon a mortise lock, it is quite as good as if it was of wrought iron. There is no unnecessary grinding, but the iron is japanned, and the japan is as much superior to the English compound as is the lacquer ware of the Japanese to that which is executed in Birmingham and palmed upon the ignorant buyer as Japanese work. In fact, as you can see for yourselves, the English japan looks almost like gas tar beside the American. This American lock is a two-lever, and there is no sham about the key, which is made of some kind of white metal and is small and neat. This lock is only 21/2 per cent higher in price than the English.

Before leaving these locks, let me say a word or two upon the relative wear upon their different portions, and their relative safety. The English maker appears to ignore the fact that nineteen-twentieths of the wear of a lock is upon the latch, spindle, and follower; the amount of actual wear upon the rest of the lock is comparatively slight. Let any of you consider the number of times you open and close a door, compared with the times you lock it. Our drawbacks and large rim locks are used about once a day; the great bulk of our mortise locks are not used, except as latches, once a week. One argument used by our manufacturers against the American lock is that, being made by machinery, there is necessarily a great duplication of parts, and a consequent lowering of the standard of security; while their own locks, being made by hand, are not alike, and therefore cannot be so easily opened.

Let any of you put this argument to proof, by trying how many front doors you can open with one key in a row of workmen's dwellings such as are found in Manchester, ranging up to L25 rentals, and the result will astonish you. If our own manufacturers made their locks sufficiently well to give this security, there would be some force in what they say; but so far as security is concerned, they might as well make their locks by machinery as make them in the way they do.

I now show you two thumb latches, one of American and one of English make. Notice the general finish of the American latch; the shape, the mode of construction, and everything about it proves that brains were used when it was designed and made. The English "Norfolk latch," on the other hand, is ill designed, uncomfortable in hand, clumsily finished, the japan hangs about it in lumps, the latch is clumsy, the catch is clumsier, and the keeper, a rough piece of hoop iron, seems as if designed to "keep" the latch from doing its duty. In this case the American latch is 25 per cent cheaper than the English one; and the English latch is of the same pattern as the one that was in use when I was a boy, only that it is a greatly inferior article.

I will now introduce you to the well known nuisance which we have been accustomed to use for fastening our cupboard doors—the cupboard turn—and without further comment, ask you to compare it with this neat and simple latch of American make, costing about 5 per cent more, twice as efficacious, and five times as durable. In this case no improvement has been made in the English fastener. It is just as it was when I went to the trade, about 28 years ago, and although many attempts have been made to improve it they have added so much to its cost as to prevent the improved articles from coming into general use.

The difference between the English and American inventor and designer seems to consist in this—that while an Englishman devotes all his energies to the improvement of an existing shape, the American throws the old article under his bench and commences de novo.

I think I have made out a case against the English hardware manufacturer, but when I have pointed these matters out to merchants and ironmongers, I have been met with various reasons for this manifest inferiority. I do not know how far these excuses may be valid, but one man says that the reason, as regards locks, is somewhat as follows: The locksmiths of the district wherein they are made in many cases work at their own homes; one man making one part of a lock, while other men make other parts. This goes on generation after generation, and the men become mere machines, not knowing how the entire lock is constructed, and not caring to know. Another attributes it to the influence of the trades-unions, and says that if a manufacturer wants a different kind of lock, the price for the work is immediately put higher, even though the actual labor may not be increased. A third says it is due to the drunkenness of the hands, and their consequent poverty and physical and social demoralization, which prevents them from rising to such an intellectual level as will enable them to see the evils of their system, and adopt the right means to remove them. A fourth boldly says, "We make these goods because our customers want them." How far the reasons assigned by the first three are correct I am unable to say, but for the fourth, the extent to which the builders of England have patronized the Americans is a complete answer.

This defense, "Our customers want them," is as old as the hills, and has been used to cover every kind of deception and inferior article ever manufactured. Our Lancashire manufacturers use it when they are charged with sending china clay and mildew (and call it calico) for the mild Hindoo and the Heathen Chinee to dress themselves in. Our butter merchants use it when they make up grease and call it butter; and our hardware merchants use it when they send us sham locks, and call them brass bushed, etc.

It is the duty of the manufacturer to invent for his customers, and it is preposterous to say that the builder would prefer that embodiment of fraud—the English rim-lock, which I showed to you—to the American lock, which, at any rate, was an honest article, especially when the latter had the great advantage of being considerably cheaper. I am afraid that the swindling and greed of our merchants is having the effect of thrusting us out of the markets of the world, including our home markets; and when it is too late, these men who are making the name of English goods a byword and a reproach, even among the Hindoos, the Chinese, and the untutored savages of the South Sea Islands, will find that "honesty is the best policy."

We have been accustomed to hear a deal of buncombe talked about the honesty of the Englishman, and the want of honesty of the Yankee; about the enterprise of our manufacturers and the skill of our workmen; but if what I have shown to you is to be taken as a specimen, it is time we set our house in order. Since commencing the paper I have read the discussion between Messrs. Chubb and Hill, and am at a loss to know why Messrs. Chubb entered into the arena. If all the English makers tried to reach Chubb's standard we should keep our markets, at least so far as high quality is concerned; and to see Messrs. Chubb acting as champions of the English lockmakers is something like seeing Messrs. Horrocks taking up the cudgels for those people who manufacture china clay and call it calico, the proportion of fiber in the material being just a little greater than that found in hair mortar.

In conclusion, I wish it to be understood that I bring these facts before you in no exultant spirit. I am an Englishman, and the future welfare of myself and my children depends very much upon the future of English manufactures; but we cannot be blind to the fact that the apathy and conservatism of our manufacturers, the greed of our Merchants, and the ignorance and drunkenness of our workmen, are weighing us so heavily in the race for trade that a member of our own family, whose leading business should be to produce food for us, is outstripping us with the greatest ease. Our boasted supremacy as a manufacturing people is leaving us, and leaving us under such humiliating circumstances—and if the men of Birmingham and the district are content to dwell in their present "fools' paradise," it is the duty of every lover of his country to speak as plainly as possible to them.

Of course I am prepared to be told that as I am not a lockmaker my opinion is worthless; but I have been about 28 years as man and boy, employer and workman, in the building trade, and if I have not got to know something about builders' hardware during that period, I have made but a poor use of my time. I do not know if I have added to your stock of knowledge, but deeming the subject an important one, I have done the best I could in the time at my disposal.

In the discussion which followed the opinion of the members present was unanimously in favor of the American articles shown to them.

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A high Indian official reports that the people of Cashmere are dying of famine like flies, and at the present rate of mortality the province will be nearly depopulated by the end of the year.

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TO INVENTORS.

An experience of more than thirty years, and the preparation of not less than one hundred thousand applications for patents at home and abroad, enable us to understand the laws and practice on both continents, and to possess unequaled facilities for procuring patents everywhere. In addition to our facilities for preparing drawings and specifications quickly, the applicant can rest assured that his case will be filed in the Patent Office without delay. Every application, in which the fees have been paid, is sent complete—including the model—to the Patent Office the same day the papers are signed at our office, or received by mail, so there is no delay in filing the case, a complaint we often hear from other sources. Another advantage to the inventor in securing his patent through the Scientific American Patent Agency, it insures a special notice of the invention in the SCIENTIFIC AMERICAN, which publication often opens negotiations for the sale of the patent or manufacture of the article. A synopsis of the patent laws in foreign countries may be found on another page, and persons contemplating the securing of patents abroad are invited to write to this office for prices, which have been reduced in accordance with the times, and our perfected facilities for conducting the business. Address MUNN & CO., office SCIENTIFIC AMERICAN.

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BUSINESS AND PERSONAL.

The Charge for Insertion under this head is One Dollar a line for each insertion; about eight words to a line. Advertisements must be received at publication office as early as Thursday morning to appear in next issue.

Valves and Hydrants, warranted to give perfect satisfaction. Chapman Valve Manuf. Co., Boston, Mass.

Brown & Sharpe, Prov., R. I. Best Gear Teeth Cutters and Index Plates at low prices. Send for catalogue.

Wanted—Galvanic Battery, Induction Coil, Electro-Magnet. Address, with description and price, Box 1700, Boston, Mass.

New Steam Governor.—Entire right for $3,000. For circulars address E. Towns, Cisne, Ill.

Gutta Percha, pure and sheeted, for sale in quantities to suit. Anderson & Reynolds, Salem, Mass.

The new fragrant Vanity Fair Cigarettes. New combinations of rare Old Perique and Virginia.

Wanted—Second-hand Corliss Engine, 100 to 125 H. P. Address P. O. Box 1208, New Haven, Conn.

17 and 20 in. Gibed Rest Screw Lathes. Geo. S. Lincoln, Hartford, Conn.

"Downer's Anti-Incrustation Liquid" for Removal and Prevention of Scales in Steam Boilers, is spoken of in highest terms by those who have given it a thorough trial. Circulars and price lists furnished on application. A. H. Downer, 17 Peck Slip, New York.

Mr. W. B. Adams, one of the most extensive contractors and decorators in this city, says he has used nearly fifty thousand gallons of H. W. Johns' Asbestos Liquid Paints, and after an experience of twenty years with white lead and other paints, he considers them not only superior in richness of color and durability, but owing to their wonderful covering properties, they are fully 20 per cent more economical than any others.

New Pamphlet of "Burnham's Standard Turbine Wheel" sent free by N. F. Burnham, York, Pa.

Gaume's Electric Engine. 171 Pearl St., B'klyn, N. Y.

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Eagle Anvils, 9 cents per pound. Fully warranted.

Case Hardening Preparation. Box 73, Willimantic, Ct.

Vertical Burr Mill. C. K. Bullock, Phila., Pa.

Sheet Metal Presses, Ferracute Co., Bridgeton, N. J.

Mundy's Pat. Friction Hoist. Eng., of any power, double and single. Said by all to be the best. J. S. Mundy, Newark, N. J.

Auction Sale.—The Machinery and Property of the well known Hardie's Machine Works, 62 and 64 Church St., Albany, N. Y., will be sold March 26, at noon. No postponement.

To Manufacturers or Capitalists.—A rare chance to control a valuable agricultural patented implement. Address S. A. Fisher, Maplewood, Mass.

Reflecting Telescope, 61/2 inches aperture, well mounted, price only $70. J. Ramsden, Philadelphia, Pa.

See Hogins' Laundry Table, illustrated on page 194. State, Canada, and entire right for sale.

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The SCIENTIFIC AMERICAN Export Edition is published monthly, about the 15th of each month. Every number comprises most of the plates of the four preceding weekly numbers of the SCIENTIFIC AMERICAN, with other appropriate contents, business announcements, etc. It forms a large and splendid periodical of nearly one hundred quarto pages, each number illustrated with about one hundred engravings. It is a complete record of American progress in the arts.

Gold, Silver, and Nickel Plater wants situation. Address Plater, Oakville, Conn.

Amateur Photo. Apparatus, including instructions; outfits complete. E. Sackmann & Co., 278 Pearl St., N. Y.

Outfits for Nickel and Silver Plating, $5 to $200. Union Silver Plating Company, Princeton, Ill.

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For Sale.—Brown & Sharp Universal Milling Machine; Bement Profiling Machine; first-class 2d hand Machine Tools. E. P. Bullard, 14 Dey St., New York.

For Sale.—7 foot bed Putnam Planer, $350. A. A. Pool & Co., Newark, N. J.

Bevins & Co.'s Hydraulic Elevator. Great power, simplicity, safety, economy, durability. 94 Liberty St. N. Y.

A Cupola works best with forced blast from a Baker Blower. Wilbraham Bros., 2,318 Frankford Ave., Phila.

Shaw's Noise Quieting Nozzles and Mercury Pressure Gauges. T. Shaw, 915 Ridge Ave., Philadelphia, Pa.

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Hydraulic Elevators for private houses, hotels, and public buildings. Burdon Iron Works, Brooklyn, N. Y.

The Lathes, Planers, Drills, and other Tools, new and second-hand, of the Wood & Light Machine Company, Worcester, are to be sold out very low by the George Place Machinery Agency, 121 Chambers St., New York.

Hydraulic Presses and Jacks, new and second hand. Lathes and Machinery for Polishing and Buffing Metals E. Lyon & Co., 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, N. Y.

Pulverizing Mills for all hard substances and grinding purposes. Walker Bros. & Co., 23d & Wood St., Phila., Pa.

Portland Cement—Roman & Keene's, for walks, cisterns, foundations, stables, cellars, bridges, reservoirs, breweries, etc. Remit 25 cents postage stamps for Practical Treatise on Cements. S. L. Merchant & Co., 53 Broadway, New York.

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Band Saws, $100; Scroll Saws, $75; Planers, $150; Universal Wood Workers and Hand Planers, $150, and upwards. Bentel, Margedant & Co., Hamilton, Ohio.

The best Friction Clutch Pulley and Friction Hoisting Machinery in the world, to be seen with power applied, 95 and 97 Liberty St., New York. D. Frisbie & Co., New Haven, Conn.

C. M. Flint, Fitchburg, Mass., Mfr. of Saw Mills and Dogs, Shingle and Clapboard Machines. Circulars.

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No gum! No grit! No acid! Anti-Corrosive Cylinder Oil is the best in the world, and the first and only oil that perfectly lubricates a railroad locomotive cylinder, doing it with half the quantity required of best lard or tallow, giving increased power and less wear to machinery, with entire freedom from gum, stain, or corrosion of any sort, and it is equally superior for all steam cylinders or heavy work where body or cooling qualities are indispensable. A fair trial insures its continued use. Address E. H. Kellogg, sole manufacturer, 17 Cedar St., New York.

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Galland & Co.'s improved Hydraulic Elevators. Office 206 Broadway, N. Y., (Evening Post Building, room 22.)

The only economical and practical Gas Engine in the market is the new "Otto" Silent, built by Schleicher. Schumm & Co., Philadelphia, Pa. Send for circular.

Dead Pulleys that stop the running of loose pulleys and their belts, controlled from any point. Send for catalogue. Taper Sleeve Pulley Works, Erie, Pa.

Vick's Illustrated Monthly Magazine is one of the most beautiful magazines in the world. Each number contains a chromo of some group of flowers, and many fine engravings. Published monthly at $1.25 per year. Address James Vick, Rochester, N. Y.

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NOTES & QUERIES

HINTS TO CORRESPONDENTS.

No attention will be paid to communications unless accompanied with the full name and address of the writer.

Names and addresses of correspondents will not be given to inquirers.

We renew our request that correspondents, in referring to former answers or articles, will be kind enough to name the date of the paper and the page, or the number of the question.

Correspondents whose inquiries do not appear after a reasonable time should repeat them.

Persons desiring special information which is purely of a personal character, and not of general interest, should remit from $1 to $5, according to the subject, as we cannot be expected to spend time and labor to obtain such information without remuneration.

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(1) S. Q.—The speed of a circular saw at the periphery should be from 6,000 to 7,000 feet per minute. The number of revolutions per minute will of course vary with the diameter of the saw.

(2) T. J. F. asks (1) for the best way to fasten emery on a wooden wheel, to be used in place of a solid emery wheel. A. Cover the wheel with leather devoid of grease, and coat the leather surface, a portion at a time, with good glue; immediately roll the glued surface in emery spread out on a board. 2. How can I fasten small pieces of looking glass on iron? A. Use equal parts of pitch and gutta percha together.

(3) W. C. asks: 1. What is the power of the simple electric light described in SUPPLEMENT NO. 149? A. When supplied with a strong current it is equal to 5 or 6 5-foot gas burners. It is designed for temporary use only. 2. What is the cost of manufacturing the dynamo-electric machine in SUPPLEMENT NO. 161? A. The one shown in the article referred to cost about $35.

(4) L. D. asks: 1. Which is the better conductor, silver or copper? A. Silver. 2. And the comparative resistance offered to the electric current by water and the above? A. Taking pure silver as 100,000,000, the conductivity of distilled water would be 0.01.

(5) H. J. F. writes: In SUPPLEMENT 162 a simple electric light is described. I wish to light a room 20x20x10 feet. 1. How large is the bell glass? A. 21/2 inches. 2. Can I use battery carbon? A. Use a carbon pencil made for electric lamps. 3. How can I make tray water tight after putting wire through? A. With gutta percha. 4. I have one large cell Bunsen and one Smee. How many more and of what kind shall I get? A. One of the batteries described in SUPPLEMENTS 157, 158, 159, will do, probably 8 or 10 Bunsen elements would be the best.

(6) W. B. F. writes: I tried to make an electric pen, like the one described in your SCIENTIFIC AMERICAN, of February 22d, 1879, using a Smee's battery, a circuit breaker, and an induction coil, but it did not work. Is there anything wrong, or is a condenser different from an induction coil? A. A condenser consists of a number of sheets of tin foil separated from each other by larger sheets of paper. One half of the tin foil sheets are connected with one terminal of the primary coil, the other half with the other terminal; the tin foil sheets connected with one terminal alternate with those of the other terminal. The condenser is essential to the working of the coil. For complete directions for making induction coils, see SCIENTIFIC AMERICAN SUPPLEMENT NO. 160.

(7) J. De F. asks: 1. Knowing the resistance of a wire of given conductivity, length, and diameter, will the resistance of any other wire be in proportion inversely? A. Yes. 2. Is there heat enough developed in the secondary coil of an induction coil to prevent the use of paraffine as an insulating material? A. With proper battery power, no. 3. How high in the list of non-conductors does paraffine stand? A. It is one of the best. 4. Will a cotton insulator soaked in paraffine answer as well as silk? A. No, because it renders the covering of the wire too thick. 5. Can you recommend any insulating material for making induction coils which will dry rapidly? A. Alcoholic shellac varnish. Rosin to which a little beeswax has been added is an excellent insulator; it must be applied in a melted state. 6. What is the composition of the black material covering the Leclanche porous cell? A. Gutta percha. 7. Is the magneto-electric machine described in the SCIENTIFIC AMERICAN SUPPLEMENT patented? A. To which do you refer? Most, if not all of them are patented.

(8) B. V. F. writes: With reference to item 8, on page 139, of SCIENTIFIC AMERICAN, March 1, 1879, I think there is some mistake about the coal you think required to heat 1,000 cubic feet space. I burn some 8 tons coal to heat, in the whole year, such part of my house as must exceed 25x20x18=9,000 cubic feet. We keep up a moderate heat at night. Ventilate more than most families do; take part only of the cool air, and only in part of the coldest weather, from the cellar, which at such times is opened into the main entries. House wood, back plastered, and stands alone. If 100 lbs. coal would heat 1,000 feet one day, I ought to burn 900 lbs. a day, or nearly 14 tons in December and 14 more in January. A. We are glad to receive these data, which correspond quite closely with some obtained by recent accurate experiments. The estimate given in the SCIENTIFIC AMERICAN also agrees well with experiments on the use of hot air heaters for very small buildings or rooms. Of course, the larger the space to be heated, the more economically it can generally be done.

(9) W. M. S. asks: Will the coil described in SUPPLEMENT NO. 160 do for the electric pen described in a recent number of the SCIENTIFIC AMERICAN? If not how must it be changed? A. It is too large; make it one half the size given.



(10) B. G.—In reply to your inquiry as to Mr. Stroh's telephone experiment, we give the following, which we clip from the English Mechanic: A singular experimental effect, of special interest just now from its possible bearing on the theory of the source of sound in the Bell telephone, has just been observed by Mr. Stroh, the well known mechanician. If a telephone, T, with the circuit of its coil left open, be held to the ear, and a powerful magnet, M, be moved gently up and down along the length of the magnet, as shown by the arrow, and at a distance of an inch or two from it, a faint breathing sound will be heard, the recurring pulses of sound keeping time with the up and down motion of the magnet. The sound may be aptly compared to the steady breathing of a child, and there is a striking resemblance between it and the microphonic sounds of gases diffusing through a porous septum as heard by Mr. Chandler Roberts. We understand that Professor Hughes is investigating the cause of this curious sound by help of the microphone.

(11) "Enterprise" asks: What part of its volume will iron expand in passing from a temperature of 60 deg. to melting temperature? A. The cubical expansion of iron for each degree (C.) between 0 deg. and 100 deg. is 0.00003546 of its volume, its volume being 1. This ratio however, increases somewhat at higher temperatures, since the mean coefficient of expansion for each degree between 0 deg. C. and 300 deg. C. is 0.00004405. The question you ask has probably never been settled. You may form an approximation by the use of the above ratios, knowing the melting point of the iron.

(12) P. L. O. asks for a good chemistry for a beginner to study without a teacher. A. Fownes' "Chemistry;" Gorup-Besanez, "Inorganic, Organic and Physiological Chemistry."

(13) L. E. M. asks: What is the best method of keeping fine guns from rusting, and what oil should be used? A. For the outside, clear gum copal 1 part, oil of rosemary 1 part, absolute alcohol 3 parts. Clean and heat the metal and apply a flowing coat of the liquid by means of a camel's hair brush. Do not handle until the coat becomes dry and hard. For the inside of the barrel a trace of refined sperm oil is as good as anything, but an excess should be avoided.

(14) A. H. B. asks how much weight, falling 10 feet, will be required to produce one horse power for five hours? A. One horse power for 5 hours = 33,000 x 300 = 9,900,000 foot pounds—so that the weight required is 9,900,000 / 10 = 990,000 lbs.

(15) A. D. R. asks: 1. In renewing a Leclanche battery, do the zincs have to be amalgamated? A. They are usually amalgamated. 2. Will two cells large size Leclanche battery give any light, using the simple lamp described in SUPPLEMENT NO. 162? A. No.

(16) H. L. J. writes: In a recent issue of the SCIENTIFIC AMERICAN you state that the floating of solid iron on melted iron is on the same principle as the floating of ice in water. I do not quite understand how it can be. Please explain. A. Solid iron, at an elevated temperature, floats upon molten iron for the same reason that ice floats upon molten ice-water—because it is specifically lighter. You will find the subject discussed at length in Tyndall's "Heat as a Mode of Motion."

(17) J. W. will find full directions for canning corn, etc., on p. 394 (4), vol. 39, SCIENTIFIC AMERICAN.

(18) "Amateur" writes: I wish to make some small bells that have a clear ring. What metal or metals can I use that I can melt easily? A. Use an alloy of tin and antimony. See SCIENTIFIC AMERICAN SUPPLEMENT NO. 17.

(19) H.—A nutritious mixed diet is unquestionably the best, care being taken to avoid an excess of meat.

(20) W. F. writes: I have made an engine, and would like to find out what size of boiler it will require. The cylinder has 21/4 inch bore and 3 inches stroke. A. It depends upon pressure and speed to be maintained; probably a vertical tubular boiler, 15 inches diameter, and 32 to 36 inches high, would suit you.

(21) R. G. (Salt Lake).—Please send full name.

(22) J. M. G. asks: If two persons each pull one hundred pounds on opposite ends of a rope, what will be the strain on the rope? A. The strain on the rope will be 100 lbs.

(23) W. M. M. asks: In laying off a mill stone in furrows, what draught is given? What amount of the space of a stone is given to furrows and what to grinding surface? A. There is considerable difference in the practice of various millers, and we would be glad to receive communications from those experienced in the art of dressing millstones.

MINERALS, ETC.—Specimens have been received from the following correspondents, and examined, with the results stated:

S. (New Orleans.)—The powder consists of a mixture of zinc oxide and finely powdered resin. A quantitative analysis would be necessary to determine the proportions.

Any numbers of the SCIENTIFIC AMERICAN SUPPLEMENT referred to in these columns may be had at this office. Price 10 cents each.

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COMMUNICATIONS RECEIVED.

Life Preserving Stone. By J. D. W. On Ventilation. By D. W. What is Mental Action? By N. K. Panama Railroad or Canal. By G. R. P. A Problem. By K. On the Gary Motor. By G. F. M. Magnetic Motor. By G. W. W., W. A. A., G. H. F. House Warming. By H. B. F. The Injector. By M. A. B. Columbus' Problem; Cure for Diphtheria; The Mullein Cure for Consumption. By R. W. L. A Visit to Tula. By L. R. On Vacuum in Pumps and the Atwood Machine. By P. J. D. On the Patent Bill. By R.

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[OFFICIAL.]



INDEX OF INVENTIONS

FOR WHICH

LETTERS PATENT OF THE UNITED STATES WERE GRANTED IN THE WEEK ENDING

February 18, 1879,

AND EACH BEARING THAT DATE.

[Those marked (r) are reissued patents.]

A complete copy of any patent in the annexed list, including both the specifications and drawings, will be furnished from this office for one dollar. In ordering, please state the number and date of the patent desired, and remit to Munn & Co., 37 Park Row, New York city.

Air heater, W. Pickhardt 212,499 Anchor, A. F. White 212,340 Animal trap, S. J. Bennett 212,430 Axle box, vehicle, P. K. Hughes 212,382 Axle, carriage, C. H. Kendall 212,387 Axle for wagons, trussed, J. Herby 212,378 Axle, vehicle, C. H. Kendall 212,386 Barrel cover, C. Brinton 212,350 Bed bottom, J. Flinn 212,451 Bed bottom, spring, W. B. Crich 212,443 Bedstead, sofa, A. N. Hornung 212,312 Bedstead, wardrobe, H. P. Blackman 212,348 Belt hook templet, E. Card 212,353 Boot and shoe laster, L. Graf 212,460 Boot and shoe sole polisher, etc., O. Gilmore 212,372 Boot and shoe sole edge trimmer, C. H. Helms 212,311 Boot fronts, cutting in, C. H. Colburn 212,357 Boot, India-rubber, G. Watkinson (r) 8,587 Bottle filler, W. S. Paddock 212,494 Bread board, H. Van Doren 212,334 Brick, shed for drying, C. H. Roselius 212,511 Bridge gate, A. Stempel 212,329 Broom corn tabler, G. W. Foulger 212,454 Button F. E. Williams 212,418 Calculator, tax, P. F. Pettibone 212,498 Car coupling, G. R. Hamilton 212,462 Car coupling, S. A. Haydock 212,464 Car coupling, J. Worrall 212,529 Car heaters, coupling for pipes of railway, J. W. Graydon 212,376 Car heater, railway, J. W. Graydon 212,375 Car heating pipe coupling, railway, J. W. Graydon 212,374 Car ventilation, J. Knipscheer 212,475 Cars, heating, J. & J. W. Russell 212,403 Cars, supplying water to wash stands on, D. H. Jones 212,385 Carbureter feed regulator, W. H. Reed 212,502 Card machine burr conveyer, W. C. Bramwell 212,435 Carpet beater, J. L. Leach 212,476 Carriage, C. H. Palmer, Jr. 212,397 Carriage bow, F. H. Niemann 212,491 Carriage, child's, F. H. Way (r) 8,583 Carriage top prop, J. P. Simpson 212,519 Carriage canopy top, D. Gleason 212,458 Cartridge, W. W. Hubbell 212,313 Chair foot or leg rest, M. E. Keiran 212,474 Chimney, locomotive engine, H. R. Walker 212,414 Chuck, lathe, J. H. Vinton 212,413 Churn power motion, W. F. Witherington 212,527 Cigarette, C. C. Millaudon 212,392 Coat, reversible, N. H. Lund 212,479 Cock and faucet, etc., self-closing, J. Broughton 212,436 Coffee pot, teapot, etc., stand, D. H. Murphy 212,395 Coffee roaster, R. Davis 212,445 Corset, W. Thomas 212,411 Corset steel, E. M. Smith 211,520 Dental plugger, W. G. A. Bonwill 212,434 Door securer and combined tool, P. E. Rudel 212,512 Door sill and carpet strip, S. M. Stewart 212,521 Drip pan and self-oiler for bearings, R. B. Eason 212,449 Egg cup and opener, D. H. Murphy 212,394 End gate, wagon, W. H. Parkin 212,398 File, bill, E. H. Owen 212,493 Files, recutting, M. J. Murphy 212,490 Filter, J. W. Lefferts 212,477 Firearm, breech-loading, H. Goodman 212,459 Firearm lock, Kaufmann & Warnant 212,473 Fire extinguisher, D. T. Perkins 212,322 Fires in buildings, extinguishing, C. Barnes 212,346 Fluid motor, Chase & Bowker 212,356 Fountain tip, H. G. Fiske 212,368 Furnace, G. B. Field 212,366 Game apparatus, W. T. Ebert 212,304 Garter, etc., clasp, L. Lobenstein 212,390 Gate, McKinley & Ellis 212,482 Gate, G. W. Pyle 212,501 Glassware, decorating, H. Feurhake 212,365 Glassware shaper and finisher, Atterbury & Beck 212,421 Glazier's tool, W. H. G. Savage 212,515 Governor and friction brake for machinery, speed, T. A. Weston 212,337 Grain drill, C. F. Davis (r) 8,589 Harness breeching strap, H. Holt 212,467 Harrow, toothless, J. W. Mulvey 212,393 Harvester, W. A. Wood 212,528 Harvester cutter, B. Pratt 212,323 Harvester, grain binding, J. F. Appleby 212,420 Harvester reel, B. Moreland 212,318 Harvesting machine, Dutton & Tornquist 212,303 Hat formers, web tender