Volume 24 (1872) (424 pages)

February 17, 1872.] SCIENTIFIC PRESS. 99 HV ECHANICAL ‘PROGRESS. Asbestos for Piston Packing. We eondense the following from the Engineer :—Few engineers who have to do with the steam engine are ignorant of the tronhle which is mct with in ohtaining a really good piston-rod packing. Sound hemp, properly “laid np,” aud copiously lubricated, makes a tight joint for a timo; hnt the period of tightness is usnally short, and munch friction results, which is very prejudicial in small engines. If hemp is bad in the caso of low-pressure engines, it is infinitely worso with high steam. A slow process of carbonization appears to go on, tho hemp packing loses its elasticity, and hecomos nearly useless for its intended purposo. All mannor of schemes have beeu tried to get over the dillicnlty, comhinations of cotton, indiarnhber, and wire gauze. In tho latter easo the tightnoss of the joint is no donbt secured hy the prosenco of water and oil lodged in the meshes of the ganzo. [No mention is made by the Engineer of auy motallic packiug othor than this ‘‘ wire gauze.”] It is still certain that somothing hetter than anything hitherto iu uso is reqnired, and wo have a stroug heliof that this something may bo supplied hy asbestos. Asbestos is a mineral fibre, greasy to the touch, and very strong, which can bo easily spnn or woven if proper precantions are nsed. Jurthermore, it is an admirahle non-conductor of caloric, and is practically indestrnetible hy heat. All these conditions are just those which are required in @ material for piston packing; and itis therefore somewhat strange that until a very recent period no one thought of utilizing ashostos for this purpose. This packing was first used in America with much success, and it has sinco heen tosted in England with excellent results. The inventor, Mr. J. V. Day, on the 5th of September last read a paper hefore the Engineers’ Institute of Scotland, from which it appears that no matter how high the temperatnre of the steam, how rapid the stroke of tho piston, or how grest the pressuro of the steam, the packing seoms to he unaffected by these conditions. Where the new packing was first used, some of it was taken from the piston-rod stuffing box of a locomotive engine, after having heon in, and the engines at consstant work, for three months, with steam at 130 tb. pressure, and making an average daily run of 100 miles, including Sundays; and tho fihre, (a sample of which wss shown), with the exception of being discolored by oil and iron, was just ss flexible and tenacions as origiually. After having been once disintegrated, it appears impossiblo to so pack or mat the fibres together that they are not eusily sepsrated by the fingers. Asbestos packing was first used in Great Gritain by Mr. Benjamin Conner, locemotive superintendent of the Caledonian Railway, and Mr. Day exhibited to the members of the Institute the packing of a locomotive stuffing hox which had been nsed on that line from the 27th of July, 1871, to the 18th of November, where the ordinary packing lasts, on their locomotives, two months, at most, rarely so long, and the gland requires constant screwing np. The asbestos packing was apparently as good as when put in, and the engine had run a distance of 14,070 miles; during three weeks of which timo, although the engine hsd run 2,000 miles, the gland screws had never been touched. In the course of the disenssion Mr. Connor stated that he hsd applied it coiled round the piston rod continuonsly; but he thought it shonld he applied in rings. The inside of tho packing seemed to him as fresh as when first putin. He believed it took less oi] to lubricate the piston-rod, for the oil remained on the rod, not heing absorbed by the packing. It kept the rod beautifully polished, more so than by any other packing. Cheap City Transit. There is at this time no more important qnestion demanding a solution from our inventors and mechanics, than that of cheap transit for the clerk, artisan and merchant from the shop or place of business to the dwelling, which points, in a large city, must of necessity he quite widely sepsrated. To this must also be added the better housing of the working classes, now imperatively urged as a necessary means of national progress. It has been proved that the largest source of profit to transit companies is “third class”—in other words, the great masses of working humauity. ‘The linmanizing influonce of gardons may bo accessible to some of the families of working men, as distance vanishes by mechanical fscilities. If commercial stimnIns induces progress in this direction, it will bea great advance on the morsls, prosperity, and happiness of our grest commercial and mannfacturing oities; hnt till wo can get mechanical powor suhstitnted for horso flesh as the means of tran: sit, we shall ho as far behind in tho rosults as are omnibnses aud stage coaches compared with railways, at a given cost, doing only one-cighth of the work. Next to choapness is tho necessity for increased speod. The averago speed of the horse car is ahont four miles per hour, snd that is accomplished only with serious distress and wear to horso ficsh. What we need in this direction is the power to increase or diminish our speed at ploasure, according to safety. Wo cannot do this till we are ablo to resort to the power of steam or clastic gases. One, great reason why we havo not done this is hecauso we have not yet preduced an engine comhining simplicity and officiency with tortuitous transit. Our ordinary railway engiuos can only run on largo curves, snd then at a great cost and waste of powor. They cannot run at all, practically, on such short curves as are required for the ordinary purposos of street railroads. The control of tho steam blastand smoke is another mattor which has not yet reached a satisfactory couclusion. The discharge of steam must he so controlled as to he comparatively noisless, while the consumption of fuel must be so perfect that nothing hut the ahsolutely invisihle products of combustion are thrown off. Revolution in the Method of Grinding Substances. Tho principal applied in grinding substances has thus far heen always a crushing betweeu two hard surfaces combined with a motion of one or hoth, as in treating cereals, paints, drugs, and in genoral most things which we wish to suhdivide finely. It has been reserved for our time, says the Manufacturer and Builder, to make a new application of a well known mechanical principle in order to accomplish grinding or pulverizing by the effects of high velocities, from which some startling results obtained by bodies moying with great rapidity have been known for a long time; such, for instsnce, as fring acandlo from a musket through a wooden board; cutting, by means of a rspidly-rotating disk of paper, suhstances much harder than paper itself; incising figures on glass by rapidly-rotating disks of metal ete., in all of whioh cases the velocity of the candle or paper compensated for its softness, and the velocity of the motion of the molecules, constituting the soft substance, produced nnexpected results. This same principle of high velocities is now being applied to grinding—a very different and more useful operation, and, in fact, one without which man can scarcely exist. The barharian grinds, or rather crushes his corn by meaus of a bowl and rolling stone, or a mortar and pestal; while civilized man thus far has ernshed his cereals between rotating stones. This is altogether to be reformed. The New York Attrition Pulverizing Company make machines after Ryerson’s patent, obtained two years ago, in which high velocity obtained by centrifugal power accomplishes the object without crushing. Tho difference in the power required for grinding by the old and new systems is most striking. For grinding 3 tons of marble or plaster to a powder, the power required to drive common Ryerson stones is from 2 to 3-horse power, while in this machine a single horse-power is sufficient to accomplish this, while it is also able to impalpahly pulverize quartz as well. [The principle of the Ryerson machine has been tried in this State for reducing quartz, with unsatisfactory results. It is possiblo, however, that; his more recent patent may comprise improvements which have rendered the principle a practical one.—IEp. Press. ] Meastrine THe SPEED oF Sairs.—The reel hitherto used to measure the speed of ships is another time-honored institution that is passing away. The rhysimeter is an instrument which permanently connects the water with an indicator in the captain’s room, marking the exact speed at all times. re HCIENTIFIC Proaress, Current Scientific Progress. Scientifio investigation wss never making moro active or earnest progress than at the present time; and in no department of research is this progross moro mauifest than in that of Chemistry, In which soveral new suhstances have heen hronght to light within the past three or four months. Among them are mentioned regianine, discovered in the walnut; acridine, 8 new substance derived from anthraeito; carnine, found in flesh, ete. Within the peried mentioned, Solet has also announced the discovery of two distinct spectra iu the flame of sulphur. In Astronomy The principal interest has centerod in tho ohservations connectod with the return of Encke’s and Tuttle’s comets. Some most interesting spectroscopic observstions on the light of these hoedies have already heen announced, snd others may ho expected, The eclipse of the sun in December last has also furnished an important field of research. Two new asteroids hsve also been announced, making the numher of tho series, so fsr as now known, 117, In Meteorotogy Constant and satisfactory progress is heing msde. The establishment of the Signal Service of the United Ststes is sn important movement, and gives promise of much practical as well as scientifio utility. A paper has heen published by Strentz which shows as to the result of a careful comparison and study of numerous observations, that the moon does not exercise any appreciable influence upon the westher, contrsry to the common idea, and the opinion of some eminent writers. In Tsrrestial Physics, We have some interesting reports of experiments in India with the pendulum for the determination of the mass of mountains, from which it would appesr that the density of the earth, at the surface decreases 88 we proceed from the sea coast to higher elevations and mountain ranges. These ohservations and conclusions are highly interesting. Prepsrations are also heing made for a series of pendulum and thermomeétic observations at the Mount Cenis tunnel, from which interesting results are expected. Geography Has been essentially advsnced, by the publication of various memoirs and reports of expeditions, among which may be psrticularly mentioned the trip of the Ice Bear, which left a nothern port of Europe only in May Isst, and returned in October, haying penetrated to 79° north on the 438d parallel of Hast longitude. An open polar ssa was easily resched. The departments of engineering, mechsnics, technology, zodlogy, and physiology, have also received many valuahle contributions. Frowsrrs as Disrxreorants.—Professor Mantegazza has recently discovered that ozone is developed by certain odorous flowers. A writerin ‘‘Nature” states that most of the strong smelling vegetahle essences, such as mint, cloves, lavender, lemon, and cherry laurel, develop avery large quantity of ozone when in contact with atmospheric oxygen in light. Flowers destitute of perfume do not develop it, and generally the amount of ozone seems to be in proportion to the strength of the perfume emanated. Professor Mantegazza recommends that in marshy districts and in places infested with noxious exhalations, strong-smelling flowers should bo planted around the house, in order that the ozone emitted from them may exert its powerful oxidizing influence. So pleasant plan formakinga malarious district salubrious only requires to he known to he put in practice. Curious Faor (?) —At a recent sitting of the Fronch Academy of Sciences, a curious communication was received from M. Yaliwski, which, if it were borne out, would he invaluable to navigation. He states that if a hollow cylinder made of thin materials, open at the top and provided with a sharp-edged bottom, be properly ballasted and then put into a tub or other vessel filled with water, it will soon move in a never-varying direction from west to east. The round tin boxes in which concentrated milk is preserved will do perfectly for the experiment, which will hecome more and more perceptible the oftener the same cylinder is made to do duty in that way.— Engineer. The Origin of the Heat of Fire. The origin of the heat doveloped during combustion has hitherto heen a profound mystery. In the beginning of this century it was suggested that a portion of the spocific or of the latent heat of the bodies consnmed was set free dnring the process of combustion; but this ides was soon overthrown, as it was found that tho products of combustion often possess more specifio heat, and almost always more latent heat, than the hodies themselves did hefore burning—that is, before chemically combining under evolntion of heat, ‘To illnstrate:—the specific heat of oxygen is 0.21, and of hydrogen, 3.4: if, now, 8 Ihs. of oxygen comhine with 1 Ib. hydrogen, forming 9 lhs. of water, the specific heat of tho mixture must he 8>< 0.21 + 13.4, or 5.08; this,divided hy 9, to find the heat per 1Th., gives 0.56. Now, the product of this comhnstion, which is water, hss a Specific heat of 1, nearly twice ss great; but, heforo becoming water, it was first stesm, of which the specific heat is only 0.48, hut which, by its condensstion, gives off not less than 966 units of latent heat. Hence arises the question:— Whence comes all this intense heat of combustion, and the subsequent great smount of Istent heat, when the resultant substance in the end posesses more specific heat thsn its elements before comhining ? It is curious to remark that some eminent physicians hsve concluded that combustion must he “an electric phenomenon,” hut that scientists, who have studied its laws, should use this pretext for explaining fire, solar heat, volcanoes, and oren earthquskes, seems almost incredie. Notwithstanding the laws of heat and of electricity have heen thoroughly investigated, we are not ss yet sure of their ultimate nature; one thing only appears certsin, namely, that neither is a fluid, penetrating matter, but thst both are mere motions of the molecules or atoms of matter. Beyond that all is mere conjecture. Waar 1s Gone on In tHE Sun.—Recent investigations of the sun and other hesyenly bodies, by means of the spectroscope, have revealed the fact that all matter may he in a more than gaseous condition—incandescent gas of so high a tempersture that the elements are dissociated; thst is, that all chemics] affinities are destroyed, snd esch element exists separately in its uncombined condition, notwithstanding it is intermingled with the others. A descent from this exceedingly high temperature to that in whioh the chemical affinities can manifest themselves results in the comhination of the gases. The chemical affinities of the different elementsry suhstsnces thus manifest themselves only between a comparatively limited range of temperature, below and ahove which they do not operate. Even as at an extreme cold no combinations csn take plsce, so at the extreme heat of say 8000° Fahrenheit, not only no combinations take place, but all componnds are separated into their ultimate elements. On cooling and reaching 4000° or 3000°, or thereshout, the volatilized substances, or gases, will again combine, the chemical affinities come into play, and combustion will ensue, the heat of which will sgsin originate partial new dissociations. This is what continually appears to take place in the sun. AGRICULTURAL CuEmistRy.—It is a wellestablished fact that the quantity of nitrogen contained in cereal crops frequently very far surpasses the amount contained in the manured earth from whieh they are grown; and the manner in which the additional nitrogen has been acquired is one of the many puzzles of agricultural chemistry. That it is derived from the air, there is no question, but in what manner ? Has it been absorbed by the plants directly from the air, or has it heen first withdrawn from the atmosphere by some of the constituents of the soil, with which it could form compounds which were capahle of vegetable assimilation? M. Deherian seems to have succeeded in demonstrating what was never before suspected, that in the presence of organic matier oxygen combines direcily with nitrogen, forming a compound analogous to the ulmice or humic acid, produced by neutralization by an acid of the potassic solution of garden mould. Into a perfectly dry tube he introduced oxygen, nitrogen, ammonia and glucose, and on heating the mixtnre finds that a black nitrogenons matter is formed, while at the same time a portion of the nitrogen disappears from the atmosphere of the tube.—Les Mondes.

February 17, 1872.] SCIENTIFIC PRESS. 99 HV ECHANICAL ‘PROGRESS. Asbestos for Piston Packing. We eondense the following from the Engineer :—Few engineers who have to do with the steam engine are ignorant of the tronhle which is mct with in ohtaining a really good piston-rod packing. Sound hemp, properly “laid np,” aud copiously lubricated, makes a tight joint for a timo; hnt the period of tightness is usnally short, and munch friction results, which is very prejudicial in small engines. If hemp is bad in the caso of low-pressure engines, it is infinitely worso with high steam. A slow process of carbonization appears to go on, tho hemp packing loses its elasticity, and hecomos nearly useless for its intended purposo. All mannor of schemes have beeu tried to get over the dillicnlty, comhinations of cotton, indiarnhber, and wire gauze. In tho latter easo the tightnoss of the joint is no donbt secured hy the prosenco of water and oil lodged in the meshes of the ganzo. [No mention is made by the Engineer of auy motallic packiug othor than this ‘‘ wire gauze.”] It is still certain that somothing hetter than anything hitherto iu uso is reqnired, and wo have a stroug heliof that this something may bo supplied hy asbestos. Asbestos is a mineral fibre, greasy to the touch, and very strong, which can bo easily spnn or woven if proper precantions are nsed. Jurthermore, it is an admirahle non-conductor of caloric, and is practically indestrnetible hy heat. All these conditions are just those which are required in @ material for piston packing; and itis therefore somewhat strange that until a very recent period no one thought of utilizing ashostos for this purpose. This packing was first used in America with much success, and it has sinco heen tosted in England with excellent results. The inventor, Mr. J. V. Day, on the 5th of September last read a paper hefore the Engineers’ Institute of Scotland, from which it appears that no matter how high the temperatnre of the steam, how rapid the stroke of tho piston, or how grest the pressuro of the steam, the packing seoms to he unaffected by these conditions. Where the new packing was first used, some of it was taken from the piston-rod stuffing box of a locomotive engine, after having heon in, and the engines at consstant work, for three months, with steam at 130 tb. pressure, and making an average daily run of 100 miles, including Sundays; and tho fihre, (a sample of which wss shown), with the exception of being discolored by oil and iron, was just ss flexible and tenacions as origiually. After having been once disintegrated, it appears impossiblo to so pack or mat the fibres together that they are not eusily sepsrated by the fingers. Asbestos packing was first used in Great Gritain by Mr. Benjamin Conner, locemotive superintendent of the Caledonian Railway, and Mr. Day exhibited to the members of the Institute the packing of a locomotive stuffing hox which had been nsed on that line from the 27th of July, 1871, to the 18th of November, where the ordinary packing lasts, on their locomotives, two months, at most, rarely so long, and the gland requires constant screwing np. The asbestos packing was apparently as good as when put in, and the engine had run a distance of 14,070 miles; during three weeks of which timo, although the engine hsd run 2,000 miles, the gland screws had never been touched. In the course of the disenssion Mr. Connor stated that he hsd applied it coiled round the piston rod continuonsly; but he thought it shonld he applied in rings. The inside of tho packing seemed to him as fresh as when first putin. He believed it took less oi] to lubricate the piston-rod, for the oil remained on the rod, not heing absorbed by the packing. It kept the rod beautifully polished, more so than by any other packing. Cheap City Transit. There is at this time no more important qnestion demanding a solution from our inventors and mechanics, than that of cheap transit for the clerk, artisan and merchant from the shop or place of business to the dwelling, which points, in a large city, must of necessity he quite widely sepsrated. To this must also be added the better housing of the working classes, now imperatively urged as a necessary means of national progress. It has been proved that the largest source of profit to transit companies is “third class”—in other words, the great masses of working humauity. ‘The linmanizing influonce of gardons may bo accessible to some of the families of working men, as distance vanishes by mechanical fscilities. If commercial stimnIns induces progress in this direction, it will bea great advance on the morsls, prosperity, and happiness of our grest commercial and mannfacturing oities; hnt till wo can get mechanical powor suhstitnted for horso flesh as the means of tran: sit, we shall ho as far behind in tho rosults as are omnibnses aud stage coaches compared with railways, at a given cost, doing only one-cighth of the work. Next to choapness is tho necessity for increased speod. The averago speed of the horse car is ahont four miles per hour, snd that is accomplished only with serious distress and wear to horso ficsh. What we need in this direction is the power to increase or diminish our speed at ploasure, according to safety. Wo cannot do this till we are ablo to resort to the power of steam or clastic gases. One, great reason why we havo not done this is hecauso we have not yet preduced an engine comhining simplicity and officiency with tortuitous transit. Our ordinary railway engiuos can only run on largo curves, snd then at a great cost and waste of powor. They cannot run at all, practically, on such short curves as are required for the ordinary purposos of street railroads. The control of tho steam blastand smoke is another mattor which has not yet reached a satisfactory couclusion. The discharge of steam must he so controlled as to he comparatively noisless, while the consumption of fuel must be so perfect that nothing hut the ahsolutely invisihle products of combustion are thrown off. Revolution in the Method of Grinding Substances. Tho principal applied in grinding substances has thus far heen always a crushing betweeu two hard surfaces combined with a motion of one or hoth, as in treating cereals, paints, drugs, and in genoral most things which we wish to suhdivide finely. It has been reserved for our time, says the Manufacturer and Builder, to make a new application of a well known mechanical principle in order to accomplish grinding or pulverizing by the effects of high velocities, from which some startling results obtained by bodies moying with great rapidity have been known for a long time; such, for instsnce, as fring acandlo from a musket through a wooden board; cutting, by means of a rspidly-rotating disk of paper, suhstances much harder than paper itself; incising figures on glass by rapidly-rotating disks of metal ete., in all of whioh cases the velocity of the candle or paper compensated for its softness, and the velocity of the motion of the molecules, constituting the soft substance, produced nnexpected results. This same principle of high velocities is now being applied to grinding—a very different and more useful operation, and, in fact, one without which man can scarcely exist. The barharian grinds, or rather crushes his corn by meaus of a bowl and rolling stone, or a mortar and pestal; while civilized man thus far has ernshed his cereals between rotating stones. This is altogether to be reformed. The New York Attrition Pulverizing Company make machines after Ryerson’s patent, obtained two years ago, in which high velocity obtained by centrifugal power accomplishes the object without crushing. Tho difference in the power required for grinding by the old and new systems is most striking. For grinding 3 tons of marble or plaster to a powder, the power required to drive common Ryerson stones is from 2 to 3-horse power, while in this machine a single horse-power is sufficient to accomplish this, while it is also able to impalpahly pulverize quartz as well. [The principle of the Ryerson machine has been tried in this State for reducing quartz, with unsatisfactory results. It is possiblo, however, that; his more recent patent may comprise improvements which

have rendered the principle a practical one.—IEp. Press. ] Meastrine THe SPEED oF Sairs.—The reel hitherto used to measure the speed of ships is another time-honored institution that is passing away. The rhysimeter is an instrument which permanently connects the water with an indicator in the captain’s room, marking the exact speed at all times. re HCIENTIFIC Proaress, Current Scientific Progress. Scientifio investigation wss never making moro active or earnest progress than at the present time; and in no department of research is this progross moro mauifest than in that of Chemistry, In which soveral new suhstances have heen hronght to light within the past three or four months. Among them are mentioned regianine, discovered in the walnut; acridine, 8 new substance derived from anthraeito; carnine, found in flesh, ete. Within the peried mentioned, Solet has also announced the discovery of two distinct spectra iu the flame of sulphur. In Astronomy The principal interest has centerod in tho ohservations connectod with the return of Encke’s and Tuttle’s comets. Some most interesting spectroscopic observstions on the light of these hoedies have already heen announced, snd others may ho expected, The eclipse of the sun in December last has also furnished an important field of research. Two new asteroids hsve also been announced, making the numher of tho series, so fsr as now known, 117, In Meteorotogy Constant and satisfactory progress is heing msde. The establishment of the Signal Service of the United Ststes is sn important movement, and gives promise of much practical as well as scientifio utility. A paper has heen published by Strentz which shows as to the result of a careful comparison and study of numerous observations, that the moon does not exercise any appreciable influence upon the westher, contrsry to the common idea, and the opinion of some eminent writers. In Tsrrestial Physics, We have some interesting reports of experiments in India with the pendulum for the determination of the mass of mountains, from which it would appesr that the density of the earth, at the surface decreases 88 we proceed from the sea coast to higher elevations and mountain ranges. These ohservations and conclusions are highly interesting. Prepsrations are also heing made for a series of pendulum and thermomeétic observations at the Mount Cenis tunnel, from which interesting results are expected. Geography Has been essentially advsnced, by the publication of various memoirs and reports of expeditions, among which may be psrticularly mentioned the trip of the Ice Bear, which left a nothern port of Europe only in May Isst, and returned in October, haying penetrated to 79° north on the 438d parallel of Hast longitude. An open polar ssa was easily resched. The departments of engineering, mechsnics, technology, zodlogy, and physiology, have also received many valuahle contributions. Frowsrrs as Disrxreorants.—Professor Mantegazza has recently discovered that ozone is developed by certain odorous flowers. A writerin ‘‘Nature” states that most of the strong smelling vegetahle essences, such as mint, cloves, lavender, lemon, and cherry laurel, develop avery large quantity of ozone when in contact with atmospheric oxygen in light. Flowers destitute of perfume do not develop it, and generally the amount of ozone seems to be in proportion to the strength of the perfume emanated. Professor Mantegazza recommends that in marshy districts and in places infested with noxious exhalations, strong-smelling flowers should bo planted around the house, in order that the ozone emitted from them may exert its powerful oxidizing influence. So pleasant plan formakinga malarious district salubrious only requires to he known to he put in practice. Curious Faor (?) —At a recent sitting of the Fronch Academy of Sciences, a curious communication was received from M. Yaliwski, which, if it were borne out, would he invaluable to navigation. He states that if a hollow cylinder made of thin materials, open at the top and provided with a sharp-edged bottom, be properly ballasted and then put into a tub or other vessel filled with water, it will soon move in a never-varying direction from west to east. The round tin boxes in which concentrated milk is preserved will do perfectly for the experiment, which will hecome more and more perceptible the oftener the same cylinder is made to do duty in that way.— Engineer. The Origin of the Heat of Fire. The origin of the heat doveloped during combustion has hitherto heen a profound mystery. In the beginning of this century it was suggested that a portion of the spocific or of the latent heat of the bodies consnmed was set free dnring the process of combustion; but this ides was soon overthrown, as it was found that tho products of combustion often possess more specifio heat, and almost always more latent heat, than the hodies themselves did hefore burning—that is, before chemically combining under evolntion of heat, ‘To illnstrate:—the specific heat of oxygen is 0.21, and of hydrogen, 3.4: if, now, 8 Ihs. of oxygen comhine with 1 Ib. hydrogen, forming 9 lhs. of water, the specific heat of tho mixture must he 8>< 0.21 + 13.4, or 5.08; this,divided hy 9, to find the heat per 1Th., gives 0.56. Now, the product of this comhnstion, which is water, hss a Specific heat of 1, nearly twice ss great; but, heforo becoming water, it was first stesm, of which the specific heat is only 0.48, hut which, by its condensstion, gives off not less than 966 units of latent heat. Hence arises the question:— Whence comes all this intense heat of combustion, and the subsequent great smount of Istent heat, when the resultant substance in the end posesses more specific heat thsn its elements before comhining ? It is curious to remark that some eminent physicians hsve concluded that combustion must he “an electric phenomenon,” hut that scientists, who have studied its laws, should use this pretext for explaining fire, solar heat, volcanoes, and oren earthquskes, seems almost incredie. Notwithstanding the laws of heat and of electricity have heen thoroughly investigated, we are not ss yet sure of their ultimate nature; one thing only appears certsin, namely, that neither is a fluid, penetrating matter, but thst both are mere motions of the molecules or atoms of matter. Beyond that all is mere conjecture. Waar 1s Gone on In tHE Sun.—Recent investigations of the sun and other hesyenly bodies, by means of the spectroscope, have revealed the fact that all matter may he in a more than gaseous condition—incandescent gas of so high a tempersture that the elements are dissociated; thst is, that all chemics] affinities are destroyed, snd esch element exists separately in its uncombined condition, notwithstanding it is intermingled with the others. A descent from this exceedingly high temperature to that in whioh the chemical affinities can manifest themselves results in the comhination of the gases. The chemical affinities of the different elementsry suhstsnces thus manifest themselves only between a comparatively limited range of temperature, below and ahove which they do not operate. Even as at an extreme cold no combinations csn take plsce, so at the extreme heat of say 8000° Fahrenheit, not only no combinations take place, but all componnds are separated into their ultimate elements. On cooling and reaching 4000° or 3000°, or thereshout, the volatilized substances, or gases, will again combine, the chemical affinities come into play, and combustion will ensue, the heat of which will sgsin originate partial new dissociations. This is what continually appears to take place in the sun. AGRICULTURAL CuEmistRy.—It is a wellestablished fact that the quantity of nitrogen contained in cereal crops frequently very far surpasses the amount contained in the manured earth from whieh they are grown; and the manner in which the additional nitrogen has been acquired is one of the many puzzles of agricultural chemistry. That it is derived from the air, there is no question, but in what manner ? Has it been absorbed by the plants directly from the air, or has it heen first withdrawn from the atmosphere by some of the constituents of the soil, with which it could form compounds which were capahle of vegetable assimilation? M. Deherian seems to have succeeded in demonstrating what was never before suspected, that in the presence of organic matier oxygen combines direcily with nitrogen, forming a compound analogous to the ulmice or humic acid, produced by neutralization by an acid of the potassic solution of garden mould. Into a perfectly dry tube he introduced oxygen, nitrogen, ammonia and glucose, and on heating the mixtnre finds that a black nitrogenons matter is formed, while at the same time a portion of the nitrogen disappears from the atmosphere of the tube.—Les Mondes.