stead of a weight, and this turbine is put in motion and stopped by the automatic action of the machine, which cuts off the water when the holder is full of gas, and turns it on again when the quantity diminishes to a certain point. It will be readily understood that the body of the machine being made of tinned charcoal iron plates, readily transmits the heat of the air to the gasoline, and thus helps to supply that lost in the process of evaporation, whilst it is obvious that the pipes must at all times be warmer than the generator-thus preventing the tendency of the hydrocarbon vapours to the success that has attended the machine is to act upon the cone or valve to close the orifice to the burner; and the cylinder is preferably slightly tapered to a larger size at the upper part, so that when the cone or valve almost closes the aperture there is more area for the flow of gas past the edge of the upper disc. In Fig. 2 we illustrate an application of In the sketches Fig. 1 represents a ver. Hearson's patented method of burning the tical section of a governor for a gas burner hydrocarbons in street lamps. The principle is according to this invention. Fig. 2 is a similar to that of the old-fashioned naphtha sectional plan on the line shown; and Fig. lamps, but the new burner is a capital instance 3 a sectional plan looking from below on of skill and ingenuity combined, to which the bottom. Referring to Figs. 1, 2, and justice cannot be done without detailed draw-3, the outer tube or cylindrical shell has at ings. In shape the lamp is of the ordinary its lower end a screwed plug, with an street pattern, with a reservoir for benzoline on aperture for the supply of gas from the service one side of the top. A valve permits the pipe, and at its upper end a burner, B, of any spirit to flow down a vertical pipe until it ordinary kind. Within the shell is an inner reaches the retort, a horizontal tube leading to tube or cylindrical shell, C, closed at the botthe burner. This retort, which dips slightly, tom, where two or more grooves are provided so as to facilitate the formation of a trap for passage of the gas from the supply aperbetween the gas producer and the supply tube, ture, a, to the annular space between the two is filled with cotton wick, which requires occa- shells. About midway in the height of the sional renewal. To light the lamp the valve is shell, C, slits are cut for the passage of gas opened for a few seconds to allow the spirit to from the annular space to the interior of C, flow down and fill the little cup at the lower part within which is the stem carrying the two discs, of the burner, when the valve is closed. The F and G, the one above and the other below benzoline is then ignited, and blazes for a few the slits. The upper end of the stem is coped, moments in an irregular manner over the whole to act as a valve in an aperture in a cap, H, burner, which soon becomes sufficiently heated which covers the shell, and has leather washers, to generate gas. As soon as a small flame is or similar soft patching, interposed between it seen to issue from the burner tip the valve is and the upper end of A. The shell, C, is secured opened, and the lamp continues to make its. in its place by screwing in the plug, which own gas-the flame being soft and brilliant, presses the cap, H, at its upper end against the and of a size regulated by a screw pin. The washers. Thus the gas on entering passes benzoline is vapourised in the horizontal arm or by the grooves to the annular space between retort by the heat communicated from the flame and two minute jets, which serve to keep the metal of the burner hot. The vapour passing downwards first turns and rises through a small orifice placed beneath a hollow tube forming the burner proper. Here it draws with it a current of air, and reaching the burner tip is consumed as air-gas. Fig. 2 shows the latest form of this new burner, which is now practically perfect. We need scarcely allude to the superior quality of the air-gas produced by the apparatus we have described, for it is well known to be free from those sulphurous and ammoniacal compounds which render coal-gas so destructive to the handsome fittings and costly pictures adorning the houses of the wellto.do. It is small wonder then that the Sun Lighting and Heating Company, having demonstrated the value of their system by a long trial at such places as the seats of the Earl of Egmont, Lord Tollemache, Sir John Ramsden, and many others, should be receiving orders from all parts of the country. In several cases the "Sun Automatic" has been ordered to replace coal-gas works, which are often a source of trouble, and frequently of annoyance. AN A and C, thence it flows by the slits into the interior of C, between the two discs, F and G, which, loosely fitting the interior of The gas passing F flows by the aperture in h C, leave leakage passage round their edges. to the burner. When the pressure of supply increases, the upper disc, F, is raised, and the coned end of the stem being thus caused to enter farther into the aperture in H, throttles the area of outlet; and conversely when the pressure decreases, the area of the aperture in oscillations are prevented by the lower disc, G, H is increased by the descent of F. Sudden being retarded by the gas on either side of it. STUDIO GLUE.* By NELSON K. CHERBILL. GOVERNOR FOR GAS BURNERS. N improved form of governor for burner for gas has been recently patented by Mr. F. Wright, of 55, Millbank-street, Westminster, the object of which is to regulate the quantity of gas entering the burner, notwithstanding variations in pressure. To effect his purpose the patentee provides a small cylinder, in which he places two discs, connected to gether at some distance apart by a stem. The upper part of the stem terminates in a cone or valve, which faces an aperture leading from the top of the cylinder to the burner. The cylinder is closed at bottom, but has lateral orifices communicating with the gas supply pipe, and opening into the cylinder in the space between the two discs. The communition from the supply pipe to these orifices is conveniently effected by means of an annular EVERY one knows what a nuisance it is to "beat the glue-pot" when some small mend has to space formed around the cylinder by an outer be made. And most people also know that all condense. The cost of the air-gas is about casing. The discs fit the cylinder loosely, so substitutes for glue are more or less failures for 68. 6d. for a quantity yielding a light equal that gas can leak past their edges, and enter-wood-work of all kinds; and, indeed, for most kinds to that obtained from 1,000 cubic feet ing the cylinder by its lateral orifices leaks of soft substances there is no cement that is 80 of coal-gas, so that it is practically about the past the upper disc to supply the burner. thoroughly satisfactory as glue. I have found an same price as the coal-gas usually supplied in Should the pressure in the gas main increase, mends, and for general purposes where but a little is exceedingly simple way of using glue for small country places. But cost, after all, is a mere it lifts the discs and stem, and so causes the wanted at a time. The simplicity of the matter is so secondary consideration in view of the fact that great as almost to need an apology for mentioning a safe, pare, and wholesome light can be supit, but its utility is so great that I must make that plied all over a country mansion without any my excuse for writing about it. This is the trouble whatever, save the winding up of the method :-Put a pinch of Nelson's shredded gelatine machine and the pouring in of the gasoline, the into a wide-mouthed bottle; put on it a very little necessity for the latter operation being indiwater, and about one-fourth part of glacial acetic cated by a float gauge. Perhaps not a little of cone on the stem to close, more or less, the From the Photographic News. francs' worth of native gold and platinum were worked over. No such mass of this curious and rare metal was ever seen before. The very remark able relation of palladium to hydrogen may be known to many of your readers a property first observed by the late Dr. Graham, of London, the distinguished chemist and Master of the Mint, who first described what he called the occlusion of hydrogen in the pores of the most solid fused and coined palladium--a property in virtue of which palladium can imbibe, so to speak, more than a thousand times its own volume of hydrogen gas and hold it with great permanence at ordinary tempera tures. This is not a fact of merely carions scientific interest; nor is it peculiar exclusively to palladium; for Dr. Graham found that some meteoric irons, especially that of Lenarto, which he specially studied, held also many occluded volumes of hydrogen gas which had accompanied the meteor from the regions of space. Considering the enormous condensation of hydrogen occluded in palladium, Dr. Grabam was led to the not improbable suggestion that this element, which others before him had suggested might be a metal in vapour, must exist in palladium as an alloy, and he was thus led to propose for the metal the name hydrogenium. This class of facts has quite recently received great expansion by the researches of Dr. Wright, of Yale, who has followed the subject into the domain of astronomy and drawn important inferences respecting the tails of comets and nebule as connected with the occlusion not only of hydrogen, but other gases in meteoric stones and irons. This curious subject, so full of scientific interest and fertile of speculation, has a magnificent illustration in the present exhibit of Messrs. Johnson, Mathey, and Co., who show a disc of palladium within which one thousand volumes of hydrogen gas are condensed by occlusion-a volume of gas which would be represented by a column of 2,000 millimetres in height and 100 millimetres in diameter. old system. Not to dwell on particulars which are One may see to-day in the Exposition in Paris The original palladium disc had exactly 100 millimetres diameter and a thickness of precisely 2 millimetres. It was, before imbibing the enormous volume of hydrogen which it now holds, perfectly fat; and it was ganged by a ring within which it exactly fell. Now this disc is a concave mirror, the new form being occasioned wholly by the molecular displacement due to the hydrogen it has absorbed ; For a very long course of years the only method it no longer enters its gauge-ring, for its 100 milli-known for working platinum was by that first prometres diameter are now enlarged to 102.5 milli- posed by Dr. Wollaston, the treatment of its sponge retres, and its original weight of 187-3775 grams. is by the mechanical processes of swedging and forging now increased to 188-2882 grams. This remarkable with heat, and thus producing an imperfect welding abecrption of hydrogen has no visible effect upon into a mass which was never quite homogeneous, the lastre, colour, or tenacity of the palladium nor could it be of any great magnitude. Never, alloy of hydrogen, if indeed it be an alloy. The until Hare fused many pounds of platinum into perhydrogen absorbed by palladium enters this metal fect fluidity was this metal seen in a state of comwhen it is made part of the circuit of a voltaic plete uniformity of texture. Now, thanks to the battery, the gas usually evolved at the positive pole efforts of Prof. H. Sainte-Claire Deville and of being then taken into the substance of the solid Messrs. Johnson, Mathey, and Co., Hare's methods met. Palladium has about the same value as gold have been improved so that we can produce perfectly (a little more), and is as yet too rare a metal to play homogeneous masses of platinum of any desired asy very important part in the arts. Nor has it the magnitude; and the consequences are important, beauty of gold, although it has certain physical and not only for commerce and the arts, but science chemical properties which give it a scientific value. profits by it for the purpose of producing the new standards of metric unity. The pile of beautiful, New Forms of Platinum Boilers and Appa- lustrous bricks-big as common house-bricks-of ratus Fashioned Solely by Autogenous platinum, fused by the oxy-hydrogen blowpipe, as Soldering and the Hammer. seen in Messrs. Johnson, Mathey, and Co.'s exhibit, is a sight to enliven the eyes of those who remember when the fusion of a globale of this metal as large as a pea was considered a splendid class-room experi. ment! The new alloy of 10 per cent. iridium and 90 per cent. platinum, which has been adopted by the International Commission, has a density of 21 52, and combines with desirable hardness a remarkable uniformity of texture and strength. It is exhibited by Messrs. J., M., and Co. in various forms-e g., the new standard metre of a cross-section somewhat resembling the letter H, or more like four capital V's placed point to point with a space between them-a form calculated to afford combined strength and lightness. These rules are row produced from the But it will be asked what of platinum and its uses, of which we spoke at the opening of this letter? I repy that the value of platinum has been long recognised for the manufacture of boilers or stills, in which to concentrate commercial sulphuric acid after that powerful agent has attained a degree of concentration in the leaden chambers which requires the use of some containing vessel in which to comFlete the work-a substance upon which no chemical action was possible. The choice lay between glass and platinum. Glass may be and is used; but its use is attended with very great risk to the lives of the workmen; and even if the loss of life by the said that it was a most powerful oxidising disinfectant, as possessing the power of resolving and decomposing all animal and vegetable putrescent matter into primitive and innocuous forms. A stream of ozone passed through a mass of black, offensive, and putrescent blood effects a change in it as if by magic; immediately, almost as soon as the operation has commenced, all disagreeable odour is removed, it re-assumes its florid red colour, and coagulation is restored. The products of putrefac tion are not only favourable to the development of special poison germs, but such products also, by their continued action, prevent the proper oxidation which should go forward in the various tissues of the body, thus causing a predisposition to the action of any poison germs to which the body may be exposed. If ozone be diffused through apartments, or else where, it not only disinfects, by removing noxious vapours and poison germs, whatever their character may be, but, being itself in the gaseous form, it is inhaled during respiration, and, passing into the blood through the lungs, it oxidises the used-up and effete matters produced during assimilation, and the renewal of the various tissues, thus effecting in no inconsiderable manner a certain resistance to their pernicious influence if retained within the human body." Dr. Day also discussed questions of an interesting character in regard to the appearance of epidemic cholera at times when there was shown to be an unusual diminution of atmospheric ozone, and he presented some interesting tables bearing upon these points. In the section of General Hygiene Professor Wanklyn and Mr. W. J. Cooper explained a new process for the testing of air, and some interesting experiments were made, showing that the quality of the air breathed in large assemblies of people could be tested. The effect upon the minds of some people who go to theatres if they could see the quality of the air they breathe, as shown by Professor Wanklyn, would be startling in the extreme. He said the testing of air at the present time was carried out by the process of measuring the carbonic acid in a sample of air. This process was defective, because it was indirect measurement of atmospheric impurity. Good air contained about four volumes of carbonic acid per 10,000 volumes of air. When carbonic acid rose to ten volumes per 10,000 of air, the air was considered foul, not because the difference in carbonic acid had any appreciable effect, but because this excess was indirect evidence of inpurity. The examination of air was also effected by the well-known ammonia process, but that process was rendered almost impracticable by reason of the minuteness of the quantity of ammonia, and would necessarily fail altogether if the impurity were nonnitrogenous. For instance, atmospheric impurities caused by such products of combustion as carbonic oxide and acetyline. The process which he proposed for the examination of air was an extension of our new process for the examination of water, the saccessful result of which had been recently brought into public notice by publication in the Philosophical Magazine, and also at the Dublin meeting of the British Association. A strongly alkaline solution of permanganate of potash was prepared, the strength of which was determined accurately. They then allowed a known volume of this solution to act on a known volume of air, heated nearly to the temperature of boiling water. After allowing the solution to act on the air, they again determined the strength: the loss of strength represented the amount of oxygen consumed by a kuown volume of air. The purer the air the less the consumption of oxygen. PUTREFACTIVE CHANGES AND THE Embalming at the Present Day. breaking of the glass boilers is avoided, this frequent fused ingots by rolling and planing on a planing is very rapid and simple when it is compared with EMBALMING at the present day is, in Ergland, an exceptional process. The modern method the anciers. A large artery of the dead body is exposed and opened, and into tite vessel a hollow needle is inserted. The needle is firmly tied in it place. Through the needle a solution of chloride of zinc is injected slowly until it has found its way over every part. The principal art that is required in this process is to be very careful not to use too much force in driving the fluid into the tissues, and in not using too much fluid. The fluid which answers best is made as follows:-Into two pints of water, at 50° Fahr., add chloride of zinc slowly until the water just refuses to take up any more of the salt. Then add one pint of water more, and two pints of methylated spirit. The five pints so produced are a sufficient quantity for embalming an adult body. The solution can be injected quite cold, and it will find its way readily over the vessels. If expense be not considered, pure alcohol may be used instead of the methylated spirit: The effect of the solution is shown by its making the surface of the skin white, £rm, and, for a short time, slightly Abstracted from the Cantor Lectures delivered by accident is always attended with very great annoyarce and risk, and a serious loss. Formerly boilers machine-a method which secures a uniformity of or stills of platinum of large size were used, costing texture and molecular arrangement not before from 15,000 dols. to 30,000 dols. each, more possible; a guarantee that time will work no changes frequently about 20,000 3ols. But this very conin the units thus fashioned; a circumstance which. siderable amount of capital locked up in these costly as is well known, destroyed the value of the old Tele-of which several were required in each platinum units formed by the imperfect methods large acid works-was in the old manner of construc- before in use. The standard thermometric metre is 10% attended with a comparatively limited produc- also made hollow and square, and for the geodesic tos of and. Now, by a very simple modification in rule is made four metres long. Tubes of iridio the form and mode of using the platinum boilers, platinum are also exbibited, calculated by the designs trer cost is proatly reduced, and the daily product of H. Sainte-Claire Deville and Mascart, to deterof concentrated and at the same time very much mine the permanency of the physical properties of increased. The now boilers, first introduced by the new rules and the co-efficients of dilation of the Mesure Johnson, are rectangular in shape, with alloy and of mercury. corrugated bottoms, which offer extended surface, with additional strength and evaporating power; so that the economy of the new form of boiler is shown to be minut de per cent. each, in the first weight of platinum, and in the consumption of fuel, with an important eiving in the cost of attendance and T the recent meeting of the Sanitary Institute, inoon, the later being declared by an elaborate Dr. Day read a paper on the relation of report from one of the most extensive of the Con- " Ozone to Heath and Disease." Dr. Day entered finental work-art los Slan 70 per cent, over the fully into the history of the discovery zone, and } Dr. B. W. RieszaLoos before the Society of Arta. OZONE AND A METHOD OF mottled. The apparatus necessary is extremely simple. It consists of a small ordinary anatomical case, and of an injecting bottle and syringe. The bottle will hold six pints of fluid, but it need not be quite filled. The neck of it is fitted with two tubes, which make it act like the common wash bottle of the laboratory, so that when, through the tube on the right-hand side, air is forced through the syringe which is attached to the tube, the pressure on the surface of the fluid forces the fluid up the long tube in the bottle, and over the tube on the left-hand side. The left-hand tube terminates in a stop-cock, to which the needle that has to be inserted into the artery is joined. The tube leading to the bottle is of india-rubber, of an eighth of an inch bore, and may be several feet long. Before the arterial needle is tied in the artery, the stop-cock is turned off, that no fluid may pass. When the needle is fixed the stop-cock is opened, and the bottle is raised on a table three feet above the level of the lower end of the injecting tube. As a rule, the fluid will now descend by its own weight, and gravitate all over the body, but if it fail to do this, the pressure of the syringe for a short time will be sufficient to carry on the current. When the fluid has slowly diffused, until it has been all passed into the vessels, a pint of solution of silicate of soda may be injected with a syringe through the artery, by which the structures will be rendered very black; the silicate undergoing a firm coagulation in contact with the zinc. This final plan is, however, not really required. It is, as a rule, merely necessary to remove the hollow needle from the artery, tie the artery above and below the place where it has been opened, and merely close the opening that has been made. The operation is now complete. There is nothing in it of a kind to give rise to any of the sensational stories which have been raised in regard to it-that is to say, when it is properly conducted. It is not more objectionable than the ordinary examination of a body to discover the cause of death. Desiccation. In treating of embalming processes, I must not omit to mention that, in our modern days, the process of desiccation has been very skilfully and practically applied for the temporary preservation of the dead. M. Falcony is the inventor of this plan, which consists in the temporary burial of the dead in a fine sawdust, charged with a salt which has a great affinity for water. Sulphate of zinc is, I believe, the salt that answers the purpose best. Many years age, I had the opportunity of seeing M. Falcony carry eut his method, and it answered thoroughly. In cases where those who have died from infectious disease, cannot be at once buried, Falceny's plan serves an all-important hygienic purpose. It is also most practical in instances where deceased persons have to be removed some distance for burial, or where other circumstances demand a delay in intermont. Preservation of Museum Specimens of Animal Structures. Museum specimens are preserved usually by auids, which are either injected through the vessels of the structure, or made to surround the structure altogether. Alcohol is, as a rule, the preservative basis in all these cases. To the alcohol various other preservatives are added; I may say, almost without any rule whatever of a fixed kind. In the museums have visited I have found every man with his own plan, and some with a great deal of mystery added to the plan, which he could not or would not explain. Boudet and Tranchini's spirit solutions hold a prominent place, or some modifications of these. I have already supplied the details of their composition. One of the Munros, of Edinburgh, I think it was the one called Munro secundus, introduced a solution which is very useful and effective for injection. It consists of a mixture of nitric acid and pine spirit, in the proportion of one part of the acid to six parts of the spirit. In our time, M. Savory has introduced an aqueous solution which is very good, and which is composed of five grains of the bichromate of potassa dissolved in every ounce of water. Budge uses a solution for moist preparations composed as follows:-Pyroligneous acid, a fluid ounce; sulphate of zinc, an ounce; water, eight pints. This is an excellent solution, cheap and effective. in use. of ancient date, which consists in securing the exclusion of the preserved substances from the air. Thus Apicius recommends, for the preservation of vegetables, that they should be chosen before they are perfectly ripe, placed in a vessel covered with pitch, and sealed hermetically. In like manner the Roman butchers preserved the flesh of various animals without salt. They hermetically sealed and hung it in a cool place-an operation which was said to succeed well. Apicius also recommends for the preservation of pork a process of a different character. The pieces are directed to be entirely covered with a paste, composed of salt, vinegar, and honey, and to be placed in vessels carefully closed. Preservation of Animal Substances for Food. For the preservation of dry preparation, solutions of corrosive sublimate and alcohol have been most The specimens are dipped and dried. Solutions of arsenic have found favour for the same purpose, but are less steady in action than these made with the sublimate. In some museums we still see specimens prepared by what was once called the "corrosive process.' It is a plan that is not often used now, but many of the best preparations of membranous textures have been set up by it. The specimen was Erst injected with spirit, or with spirit, wax and vermilion. Then it was immersed for a month in a bath composed of four parts of hydrochloric acid to one of water. After this immersion the specimen was removed, washed, and dried. Accepting the view that the process of desiccation, or mere drying, is primitive as an invention, we are soon led to another food-preserving process not far behind this, or, at all events, very ancient; this is the salting process, or the mode of applying common salt to avert putrefaction. It has been urged that the use of this method implies, in matter of history, such a degree of knowledge as would indicate an advancing civilisation, and even some acquaintance with the simpler details of chemical science and art. Ithink this a reasonable view; and certain it is that, whenever in history we read of the method of preserving animal or vegetable substances by the plan of dressing them or of saturating them with salt, we detect that the operators lived in an age when the refinements of civilisation, and the cultivation of the useful arts, had reached a degree of perfection by no means to be considered as contemptible. The early importance attached to the use of salt has been supposed to be shown by the fact that the Greeks placed this substance in the list of things that were consecrated to the gods; so that it was considered a misfortune to spill salt, and impious to forget to place salt cellars on the tables, or to go to sleep before their removal. How far this observation may tend to place, so far back as the early Greek period, the use of salt for preserving purposes, I will not pretend to say; but we have direct evidence that amongst the Romans the practice of preservation by salt was general. The Romans sold, as our modern butchers sell now, both fresh and salted meats; their mode of preparing the salted meats being as follows:-The animals they intended to salt were kept from drinking any fluid on the eve of the day on which the killing took place. After the killing, the parts to be preserved were boned and sprinkled lightly with pounded salt. Then, having well dried off all dampness, the operators sprinkled more salt, and placed the pieces so as not to touch each other in vessels which had been used for oil or vinegar. Over the whole they poured sweet wine, covered the contents of the vessel with straw, and when obtain able kept down the temperature of the room in which the vessel was placed by strewing snow round about. This was assumed to make the meat better and more tender. When the cook wanted to extract the salt, he first boiled the meat well in milk, and afterwards in soft or rain water. The exposure of animal substances to certain gaseous preservatives is a last plan of preservation which also has its origin in a remote period. Common wood smoke is one of the preservatives which has been thus employed for various animal substances, both in past ages and in modern times. In England, too, a very old custom of preserving fruits, gooseberries especially, has consisted in filling a vessel with the fruit, then burning in the neck of the vessel a piece of sulphur, and corking up securely while yet the sulphur is burning. By this means a quantity of sulphurous acid gas has been generated, and diffused through and detained in the bottle, while at the same time, a portion at least of the free oxygen surrounding the fruit has been removed from the air previously contained in the bottle. In these appliances we discover a degree of art and of skill which shows an advancement even on the proceedings of our own age. When, for instance, the animal was prepared for the process by being deprived of water, an evidence was supplied that the operator knew the fact that animal tissue, recently dead, will absorb a solution of saline matter so much the more promptly if, previously to death, its own water has been reduced in quantity. In boiling the substance that had been preserved by salt in milk, knowledge was supplied of the physical truth that the salt would be given up the more readily to such a fluid as milk than to common water, while, in the final part of the proceeding, the preparation for the table, the use of a water itself unimpregnated with saline particles, and therefore capable of removing the largest possible amount of the preserving agent, is so admirable that we may commend it to all English matrons as a wrinkle far too deep to be allowed to pass unforgotten. There is Fet another mode of preserving food, also ALLOYS-VIII.* Zinc. lustre, and rather hard. It melts at about INC is a blueish-white metal, with considerable 773° of Fahrenheit's scale. It is ordinarily brittle, but when heated to a little above 200°, and between that and 300° it becomes ductile and malleable, and can be rolled out into the sheet-zinc in common use, ever, possesses but little tenacity. Zinc, when or be drawn into moderately fine wire, which, howmelted, burns in the air with a magnificent green light, forming flakes of zinc-oxide, sometimes called Philosopher's Wool." When exposed to the air zine soon oxidises, and the thin film of white oxide, formed over the surface, protects it from further change. Native zinc or spelter, as it is called in commerce, is never found; it has so much affinity for other matter, particularly oxygen, that it cannot exist very long in its pure state. The principal ores of zinc are zinc-blende, red zinc ore, and calamine ore. The zinc-blende is a sulphuret of zine, and is composed of 60 to 70 per cent. of zinc, and the balance sulphur; its colour is generally bright or yellowish-brown, but it is occasionally found of a black, red, green, or yellow colour. This ore is always found crystallised, and in most cases the masses of it are mere accumulations of crystals. It is transparent, or, at least, admits of the passage of light if in thin scales. This ore is found in heavy veins and masses in the gold regions of the Western Territories and Southern States. It sometimes contains silver and also gold in considerable quantities. It is sometimes associated with galena iron and copper pyrites, tin, heavy spar, black manganese, and manganese spar. This ore is chiefly worked for its gold and silver, all the zinc being lost by being either converted into cinder or washed away. The red zinc ore is the principal source from which we obtain our supply of zinc or spelter. This ore is extensively deposited in New Jersey and Pennsylvania, and is used for the manufacture of zinc or spelter. There is a very large zinc works at Bethlehem, Pennsylvania, and several large works in New Jersey. The red zinc ore is a compound of oxide of zine, manganese, and oxide of iron; its colour is a brick red with a yellowish tinge, like cinnabar. The calamine ore is a silicate of zine; it is a dirty yellow or stone colour; if pure, it consists of about one-half oxide of zinc, the other half is composed of carbonic acid, silex, iron, and other admixtures. This ore is very plentiful, and is found in heavy beds in Eastern Pennsylvania, it is found in heavy veins. It may be looked for in all the limestone rock from the most recent to the oldest formations. It is used in its pure state for sheet zinc, and for coating sheet iron, gas-pipe, &c., with, as galvanised iron: this is made by dipping the iron into a bath of molten zinc, and then it comes ont coated with zinc. Sheet zinc is sometimes used for roofing buildings, but it should not be used for foundry roofs, as the steam from the sand corrodes it, and will soon eat it full of holes. Zinc is also extensively used with other metals in forming alloys of brass, German silver, hard solder, &c. Tin. slight bint of yellow. Its fusing point is 4229 of Tin is a silvery-white coloured metal, with a Fahrenheit's scale. It is soft and not very ductile, but is quite malleable, so that tinfoil, which is From a series of articles by Mr. E, KIRK, published in The Iron Age obtained by beating out the metal, is not more than 1-100th of an inch in thickness. When quickly beat it utters a shrill sound called the tin-cry, which ing in a reverberatory furnace; the sulphur burns shoot-lead, roofs, vessels for sulphuric acid, &c. ; it Nickel. Nickel is a white, brilliant metal; it fuses at 2,732° of Fahrenheit's scale; it is ductile and malleable, acts upon the magnetic needle, and is itself capable of becoming a magnet. Its magnetism is more feeble than that of iron, and vanishes at a heat somewhat below redness. It does not oxidise by exposure to air at common temperatures, but when heated in the air it acquires various tints, like steel; at a red heat it becomes coated by a grey oxide. There is very little nickel ore found in the United States, and the only mines that are worked at the present time in the country are located in Eastern Pennsylvania; and from these mines the United States Government receive their supply of this metal for making the 5 cent. nickel coin now in use. This metal is scarcely used in its pure state, but is principally used, together with copper, zinc, and other metals, in forming alloys, and these alloys are rendered the harder and whiter the more nickel they contain. The white copper of the Chinese, which is the same as our German silver, is composed of 3 parts nickel, 5 parts copper, and 2 parts zine; this alloy sometimes contains a little iron, and a small amount of that metal seems to improve the alloy. This metal is also extensively used for plating other metals, and for this purpose it is rapidly taking the place of silver. When plated on other metals it has a silvery whiteness and receives a high polish, which lasts for years, and its hardness is almost equal to that of steel, which eminently fits it for the plating of mathematical and other delicate instruments. CARE IN DRILLING AND BORING. BY JOSHUA ROSE, M.E. Wome engine cylinders to fit up, and in get- sel by the destruction of cohesion and the crystals moving upon each other. When a bar of tin is rapidly bent backward and forward several times successively, it becomes so hot that it cannot be held in the hand. When rubbed it exhales a peculiar odour. Tin does not oxidise rapidly at an ordinary temperature. Its tendency to crystallise is remarkable. Tin, though one of the metals longest known to man, is found in but few localities. There are but two ores of tin known which are of any practical use. One of these is tin-stone or peroxide of tin. The other is sulphuret of tin or tin pyrites. No tin is manufactured in the United States at present, although tin-stone is found in the New England States, and is said to have been discovered in Missouri. This, however, is doubtful. Tin-stone occurs chiefly in granite in heavy masses or lodes mixed with conglomerates of various rocks. It is also found in alluvial gravel as the result of the decomposition of the above rock, and is then called stream tin. Tin stone is of a variety of colours, white, grey, yellow, red, brown, and black. Its most striking feature is its weight. Tin pyrites are not very abundant, and cannot be considered an ora of tin. Their presence in the silver ores of the Southern gold region is so limited as to render the extraction of the metal unprofitable. This ore is of a grey or yellowish colour, heavy, crystallised, and of a metallic lustre. Tin is extensively used with other metals in forming alloys of pewter, britannia, brass, bell metal, so't solder, fusible metals, &c. Pure tin is commonly used for dyers' kettles. It is also sometimes employed for the bearings of locomotives, carriages, and other machinery. Common sheet tin is formed by dipping sheet iron in a bath of melted tin covered with oil, or with a mixture of oil and common resin. They come out thoroughly coated with tin. Tinned iron-ware is similarly prepared. Cast-iron hollow ware is tinned by heating the ware to redness, and putting molten tin into the pot or kettle intended to be tinned, and spreading it over the surface with a piece of cork. Sal-ammoniac or resin may be used as a flux. Pins made of brass wire are boiled with granulated tin, cream of tartar and water, which gives a bright Antimony is of a silvery-white colour, with white surface to the pins. Mirrors are silvered with beautiful laminated star-like crystalline structure, an amalgam of tin and mercury. The process is as and is very brittle. Its fusing point is about 600° follows:-Tinfoil is first spread evenly upon a marble of Fahrenheit's scale, or at a dull red heat, and it is New Method of Cooling and Purifying Air. table, and then the mercury is carefully poured over volatile at a white heat. Antimony is commonly-The Iron Age says that at Messrs. W. D. Andrews it. The two metals combine, forming a bright found in the form of a sulphuret, which is very and Brothers' iron foundry in Water-street, in New amalgam. A clean, dry plate of glass is then care- volatile, easily fused, and requires great caution in fully pushed forward over the amalgam, so as to roasting. The sulphur cannot be entirely separated York, there may be seen in operation a novel appacarry the superfluous mercury before it, and also by roasting, and this causes the roasted matter to consists of a cylinder 3ft. in diameter and 4ft. high, ratus attached to the pump of a driven well. It prevent the air from getting between the glass and have a dark grey colour. A mixture of sulphuret filled with charcoal, through which water from the the amalgam. Weights are then placed on the and protoxide, the more perfectly the desulphuraglass to cause the film to adhere more closely, and tion of the ore is performed the more will the colour well percolates. A revolving fan on the upper surface in twenty-four hours the glass is removed, and in approach to a faint yellow. Impure lead ore has creates a draught, so that where the air enters the three or four weeks is dry enough to be framed. this characteristic in common with antimony, but office adjoining, a strong, cool breeze is felt, reducing This process of making mirrors is very injurious to before roasting it is not difficult to decide between the temperaturo very decidedly, compared with the health, and the workmen are short-lived. A antimony and lead. Antimony was discovered by extreme atmosphere, and the supply thus furnished is perfectly pure. The water has a temperature of paralysis sometimes attacks them within a few Basile Valentine, a monk of Germany, in the 55 degrees, while the air cooled by it varies from 60 weeks after they enter the manufactory, and it is fifteenth century. It is said that to test its pro- to 64 degrees near the spot where it is injected. On seldom that a man escapes for more than a year or perties be first fed it to the swine kept at the con- the occasion of our visit the outside temperature was two. The effects are similar to that of calomel. vent, and found that they thrived upon it. He then 86 degrees; within, near the cold draught, 72 degrees. The men seem to dance instead of walk, and they tried it upon his fellow-monks, but perceiving that Wherever steam is available the pump and fan can cannot steady their nerves nor direct the motion of they died in consequence, he forthwith named the their hands; and in some cases they cannot digest new metal, in bonour of this fact, anti moine (anti- be worked at a trifling expense. The question is monk), whence our term antimony is derived. suggested whether this mode of purifying and venti lating through the instrumentality of driven walls Antimony expands on cooling. It is scarcely ever used alone, but is generally used with lead, tin, and may not be applied to public halls, court roems, other metals in forming alloys. Antimony and tin banking offices, &c, so as to become invaluable-for mixed in equal proportions form a moderately hard, example, in the New Court House building, where brittle, and very brilliant alloy, capable of receiv- the foul atmosphere is extremely prejudicial to ing an exquisite polish, and not easily tarnished by exposure to the air. It has been manufactured into speculums for telescopes. their food. Lead. Antimony. Bismuth. health. Lead is a blueish-white metal; its fusing point is 620 of Fahrenheit's scale. It is remarkably flexible and soft, and will leave a black mark on paper. It is poisonous, though not immediately, a bullets have been swallowed, and then thrown off without any harm except fright; its effects seem to accumulate in the system, and finally to manifest themselves in some disease. The sugar of lead has a sweet, pleasant taste, but is a virulent poison; its antidote is Ep om salts. Lead appears to have been known in the earliest ages of the world. The most common ore of lead is galena or sulphuret of lead; this ore has the lustre and colour of polished metallic lead. It is always grey, without a shade of any other colour, but its powder, when finely rubbed, in black. It is always found in a crystalline form, the crystals being cubes, often composed of square plates, and frequently so sma'l as only to be detected by the aid of a glass; in other instances the cubes, or the plate which forms the cubes, are more than inch square. Galena is very heavy, and equal to metallic iron in specific gravity; it is the heavest of all metallic ores. Galena is very extensively distributed over the United States, and is found in Aluminium is a bright silver white metal; it is almost every State in the Union; the most extensive only one-fourth as heavy as silver; it is ductile, deposits are in the Western States. It is extensively malleable, and tenacious; it receives its name from worked on the upper Mississippi and in Missouri. alum in which it occurs; it is also called the clay Galena, containing silver, is very extensively di-metal. Aluminium is found in slate mica clay, and tributed over the whole goli region, but it is not in all the clay rocks, and from these substances we generally in use. The difficu'ty of smelting this ore profitably appears to be in the way of it more general application. Lead is also obtained from the carbonate of lead, an ore of frequent occurrence, but it rarely forms a vein of itself. The phosphate of lead is also an ore from which metallic lead is obtained. Lead is reduced from its ores by roast Terrestrial Constants.-J. B. Listing (Göttinger Gesellschaft der Wissenschaften) gives the following summary of the latest estimates of im portant geometric and dynamic constants :-Major axis of the rotation ellipsoid, which most nearly Bismuth is a brittle, reddish-white metal. It represents the form of the earth, 6,377,377 metres; fuses at 507 of Fahrenheit's scale; always crystal-minor axis, 6,355,270m.; radius of the earth, lises on cooling; is volatile at a high heat; transmits regarded as a sphere, 6,370,000m.; length of the heat more slowly than most other metals, perhaps seconds pendulum at the equator, 0 9909948; ditto, in consequence of its texture. This metal is seldom lat. 45°, 0-9935721; ditto at pole, 0-9961495; g. at used alone for any useful purpose, but is employed equator, 9780728; ditto, lat. 45°, 9-806165; ditto at for imparting fusibility to alloys of other metals. pole, 9-831603; centrifugal force at the equator due An alloy of three parts lead, 2 parts tin, and 5 parts to the rotation of the earth, 0 0339117. bismuth may be melted in boiling water or at a heat of 199° Fah., yet when these metals are melted separately, tin requires a heat of 442°, lead 620°, and bismuth 507°. 1 Aluminium. obtain our entire supply. This metal is but very Nitrification by Organized Ferments.Schlösing and Muntz conclude, from an extended series of observations, that the vegetable organisms of a lower order, such as moulds and mycoderms, which lead to the slow combustion of organic matter, do not produce nitrification. On the contrary, they transform the nitric acid, at first, into organic matter; then, at least in part, into free nitrogen, the latter phenomenon being often accompanied with the production of ammonia. Consequently, they occasion a diminution of the combined nitrogen which exists upon the surface of the globe. When the nitrogen is present under both forms in a soil, the mycodermic vegetable which is developed there assimilates in the largest proportion the ammoniacal nitrogen. In the Scientific News |