Volume 13 (1866) (424 pages)

The Mining and Scientific Dress. 15 Ld Mlechanical. ENGLISH OPINIONS. The Eagineering says: " Wo believe onr Yankee brethren make an engine better adapted to rough, aud even to ordinary lincs, than our own, and, on the other side, we consider our engines simpler aud stranger for their work. A. Yaukce hoiler would burst, by hydraulic pressure, long before ours would give way, and yot they carry as high gteam as we.” Mr. Normon Jusse} gays, respecting our beam-cnyines : The American steamboat engino has long heeu a subject of wonder to the Mnglish encinver. tis ugly, straggling, aud inconvenient louking ; its incompactness, nnd want uf snugness and vcououry of room, nuke it the reverse of everything we think good in a steainhoat engine. It aaa made the same impressiun on me that it has done on all my countrymen, but it wns at first sight, and nt rst sight only. Daily the unfavorable impression became titigated hy familiarity, nnd after a carelal study of its details and qualities, { do not think it possihlo to design an eugine more admirubly fit lor its use and purpose, puder the circamstances wheru it is applied. Ja this country there is not a sinvle enzine which can he said to be entirely English, and pre-eminently suited to ony one purpose. The American walking: benm cngine, ou the other hand, ia universal in the States, and ucknowledged to be best suited to thetr Eastern river navigation. I thiok it will be ndmitted, therefore, that the permancnce of this kind of engine in the American stenincrs must be held as prima facie proof of its oxcellence, and that it is entitled to our respectful consideration, and likely to reward our careful study. I have examined the stracture in tho best workshops of America, nod have watched its practical working in their best steamboats. I have sntisficd myself that it.is cheaper in construction, lighter in weight, more economical in management, less costly in repair, wore durahle, and better suited for high speed than any of our own engiues would be. I think that for the navigation of large rivers, like those of China and India, it might he adopted with great advantage, and many of its details, indeed, might he adopted with advantage in any engine. A New Amavcamator.—-There is now being made at the Sacramento Iroa Works, snys the Bee of that city, a newly invented amalgamator, which promises to supersede all others now in use. A miniature edition of this amalgamator has heen in operatiou in that city two or thrce months. It has operated on tailings from Nevada, KE] Dorado, Amador and other miuing counties, aud has never failed to call the cast-off tailiugs to account, advantageously. If the invention possesses all the power which the quartz miners with whom we have conversed claim for it, it isa valuable invention. Ecoxomte Resutts are obtained in burniag fuel, by feeding the fire from below, and thus consuming the fuel from the surfaco downward, instead of trom helow upward, as usaal. ‘T'he air ndmitted ig heated somewhat by the lower strata of fucl before it comes in contact with the hot coals, which assists in a very marked maaner the complete combustion of the carbon. In a puddling furaace, near Glasgow, Scotlnnd, which had consumed 41 ewt. of fuel, only twenty pounds of unburned residue was found. The modifications necessary to carry out this improvement nnder boilers are few and inexpensive, and the results so good that at the Gartness Works, near Glasgow, the weekly returns show a saving of one-third. A Goop Cement.—Gutta percha when dissolved in chloroferm, so as to make a fluid of the consistency of honey, produces a good cement. When spread, it will dry in a few momeats, but it wilksoften by heating. Small patches of leather can he cemcnted on boots hy its use, in such a manner as to almost defy detection, and some shoemakers employ it with great success for this purpose. It is waterproof, resisting all the elemcuts but heat. AN ALLoy consisting of ten parts of casl iron, ten of copper, and eighty of zine, does not adhere to the mold in castiug, and it is of a beautiful luster when filed and polished. The most fractious metals are melted first, and the zine last, in making it. 1 A German, named John A. Heyl, living in Boston, has invented a method lor lighting all the street lamps in a city siineltoneoasly. The lighting of lamps by clectricity is uo new thing, but what Mr. Hleyl claints us the new feature in his inveution isa stop-cock comLined with nn clectric battery, by means of which the operator nt any central point cau tura the gas off or on, at his plensure, at the same tine igniting it with tho clectric battery. ‘the stop-cock is the eriginal leature of the ‘invention, any numberof which can he operated at the same time hy a picce of platina wire. Ju cnsu the wiad Iiluws the gns out, it will ignite nguin of its own accord Irom the heat which is retuined ia the wires, without ony electricity whatever. San Prancrsco as A Masvuvacrurtxa Ciry. lt uppears from nn official statement, compiled froin the ccnsns of 1866, that the city of San Francisco nt that time, although rating as tho fifteenth city in puint of population, stood us high os the ninth in respect to the valuo of her inanufacturing investments and products— a most remarkable showing for a city at that time but eleven years old. Atrn-ITaumers.—Mr. Grimshaw’s high speed Birmingham for voriuus stamping and lorging purposes: at Clasgow for coppersmith’s work, and at Sheffield for steelwork. T'he aachine consists of a force-pump supplying compressed air to a reservoir, and a working cylinder and piston similar to those of a steam-hammer ; having arrangements for varying the action of the hammer as required. aad increasiag the rapidity of the blows, which aay attain a masimum of 800 strokes per minute. The largest hatomer yet put to work las a cylinder 844 in. io diameter, and a stroke of 28 in., and the pressure may be adjusted to any amount from five pounds to forty pounds per square inch. Several steam-hammers of from four to ten hundred weight are working at Sheffield, with which 506 or 600 blows per miaute can be struck if required. Wrovout Iron Drums ror Putieys.—We learn that Messrs. Hudswell & Clarke, of England, are now making a number of drams of wrought iron. ‘The drums are only ahont half the weight of those of cast iron, and by their use the weight upon the bearings of the shafting is much reduced; belts also are found not to slip on them as they do on cast iron drums, ond last much longer; ia fact, at Messrs. Hudswell & Clarke’s own works they state that they have heen enabled to reduce their belt account one-half since they have nsed the wrought-iron drums. Oxsnqur Bruts.—It sometimes happens that it ig necessary to lead a belt obliquely from a pulley or fly-wheel,and iu such cases much trouble is frequently caused by the belt slipping off. ‘This can, in very many instances, be prevented hy fastening a strap of thick leather, of a less width than the belt, around the center of the fly-wheel or pulley. The leather strip may be secured by counter-sunk copper screws passing through it, and tapped into the rim of the wheel.— Engineering. Guy Tunes.—It appears that the steel tubes of the Woolwich guns, although hardened in ofl. will not withstand the action of the powder and the bite of the shot. In many cases the steel tutes have heen deeply scored, and it isa question which, we believe, has been seriously mooted, whether they shall not, in future, be wholly abandoned.—Kngineering. Proressor Anru found that hardened steel wire dissolved in hydrochloric acid without residue, whereas the same steel in the softened state yielded by such actioa a dark flocculeat carbonaceous residue. Pror. Honexinxson has shown that strains, however feeble, if long applied, nroduced some permanent elongation or contraction in bars of iron. Tur Zanesville Courier, in noticing the contemplated visit to that city of Mr. George Peabody, the celebrated London banker, says : * Among the most henevolent deeds of this $50,000 apiece to each of his four nephews in the East—among them, Mr Arthur Peabody, former local of the Courier.” A. New York city correspondent says that the residence of A. ‘I’. Stewart, corner of Thirty-fourth street and Fifth Avenue, is nearly ready to move into. It eclipses any private huilding on the contiaent, soit is said, and will cost, without aay furniture, $2,500,000. compressed air-hammer is now employed nt ® world renowned hunianitariaa, is the gift of ~— Srientitie Alisccllany. EXTREME DELIOAOY OF PHILOSOPHIOAL INSTRUMENTS. It is wonderful to observe tho great degree of perfection to which nrt has arrived in the constraction of iustruments for philosophicnl purposes. As an evidenco ef this, we may mention a galvanometer, which was manpfnetred a few years since in the city of Berlin for the great Mnglish experimentalist, Julin Yyndetl, F R.S., ete. The galvanometer isan instrument for measuring the furce of the galvanic current. In this iustrumeat two magnetic ucedles are used, ono of whiclt is surrounded by a copper wire, insulated or encased with sik. This wire must bo absolutely pare copper; so delicate is this instrument, tf properly inade, that the least particle of iron in the copper wire will derange its action. In preparing the instruinent above nlluded to, such a derangement was noticcd, although the wire was proved to be absolutely pure. After much rescarch, the derangement was found to exist in the infinitesimally small omount of a compouud of iron used ia the green color of the silk, with which the wire wos coverod! White silk wos substituted, and the derangement disappeared, 7 Again, wo have recorded an instance of a pyroineter, constructed to mensure the degrec of heat transmitted to a piece of iron. The iron employed was an upright bar, two feot long, of sufficient diameter to stand upon its end. A mirror was connected with the top of this bar, from which a beam of light was reflected upon the wall of the room, by an electric lamp. When the bar shortened the mirror turned in one direction; if it lengthened, the mirror turned in the opposite direction. Every movement of the mirror, however slight, was multiplied by a loug index of light, which was made to move through a correspondiag space upon the wall. A mere breath projected agaiast this piece of iron produced a sensible movement of this beam of light. The contact of the flame of a spirit lamp with the iron, caused the index to move throngh a space of fully thirty feet! When it is recollected that this movement of the iadex, was caused by the mere lengthening and contraction of thal bar of iron, due to the small degree of heat applied, some idea may he formed of the delicacy of that mode of observation. Another iustance may be cited: An instrument kaown as‘ Melloni’s Pile,” which is so sensitive as a thermoscope for measuring heat, that it is said to be sensibly affected by the mere warmth of the hand, when held at a distance of six or eight feet from it. PracticaL Science —'Il'yeory anp Fact. In the study of auture two elements come into play, which belong respectively fo the world of sense and to the world of thought. We observe a fact aad seek to refer it to its laws ; weappreheud the law, and seek to make it good in fact. The oae is theory, and the other is experiment or fact; which, when ap plied to the ordinary purposes of life, hecomes practical science. Thus, by the instruction of thought and fact, of truth conceived and truth executed, man bas made science what it is— the noblest growth of modern times. Licuting or Pontic Matis py Maonestun. At the Royal Institution, Loadon, Mr. Larizin recently exhibited bis method of illuminating public halls by the combustion of magnesium. The magnesium, in a finely-divided state, is showered on smat] flames of gas, and thus produces a brilliant illumination. It was the first time the appuratus had heen publicly exhibited. The flame was flickering, hut the pure quality of the light coatrasted strongly with the usnal gas flames of the burners in the lecture theater. Ross, as s00n as the flowers have opened and bloomed one day, should have the decayjug flower cut away; cutting back to a good strovg bud, from which will come a new stem and flowers. Attention to this practice of cutting will keep plauts bloomiag almost continuously. Errects or Lignt ox Leap Patxt.—Dr. D. S. Prico, of the British Asgocintion of Science, having noticed that in the glass cases of the last exhibition at tho Crystal Palace, London, which were pointed with white lead, substunces which emitted sulphurous vapors did uot darken or otherwise effect the paint, except where the paint wns protected from the direct inflnence of the light, was thereby led to make some investigations into the subject. A uumher of expertments were tried, and among others n board was painted with white lead, and sehsequently exposed for several hours to the action of sulphureted hydrogen gas, until the entire surfaco had nequired a dull chocolate culor. Glass of different colors waa then placed upon it, leaving one portion exposed, or withuut any glass, and another portion covered with an opaque medium. The board so prepared was then exposed to the action of light,and several impressions were photographed by the light acting through the glass. Thro glasses employed were red, blue, yellow and violet. he results were that the portions exposed to the light wero bleached, that entirely protected by an opaque covering remained unaltered, whilo correspondingly intermediato effects wero produced by the differently colored glosses, varied according to the different degrees of opaqueness. Nirroteum is a new nomo given to nitroglycerine, by Col. T. P. Shafter, in his late report to the Secretaries of Warand the Navy. The Colonel had been directed to make some comparative tests with gunpowder and nitroglycerine or “nitroleum,” and the report referred to gives the results of these experiments New and Interesting Electrical Experiments. In an account of some electrical experiments reported in Poggeadorff's Annalen, M. Henrici states that if water containing hydrogen in solution be put into comraunication with ordinary water by means of a piece of moist paper, and the circuit be closed by a galvanometer, a current will be produced, directed into the galvanometer, from the ordiaary water to the watcr cbarged with hydrogen. On this fact M. Henrici bases his opiaion that a certain number of phenomena, usually attributed ‘to the action of the oxygen of the air, such as oxydization of iron and other metals, and the putrilaction of vegetable substances, are really due to the decomposition of the atmospheric moisture. Another experiment made by Professor Tait is recorded among the Inte proceediags of the Royal Society of Edinburgh, from which it appears that when a horizoutal plate is put into a state of rapid vibration, iron filiags strewn on the surface, neara point of maxinum vibration, are preveated from being scattered to the nodal lines by n magnetic pole held ahove the plate ; hut if tho pole be held below they are speedily dissipated. If too powerful a pole be used, or if the magaet he held too near the plate, the filings nenrest the pole are not dispersed in the latter case. Profossor Tait thus explains the phenomena : The filings tend to place their greatest length in the direction of lines of magaetic forces; aad thus, when the pole is ahove the plate, their upper ends incline towards it, so that the agitatiun of the platc, combined with the magnetic attraction, brings them nearer to the point immediately below the pole. When the pole is below the plate the upper ends of the filings diverge from the pole, nud the agitation sends them outwards, uuless the nagnetic attractioa be considerable, Cureap Execrricrry.—In a recent note sent to the Academy of Scieaces by M. Gerardia, “Ona Battery of Iron Turnings,” he thus describes the apparatns : “I replace the zinc of a Bunsen's battery by iroa borings; an iron bar placed in the middle of the borings serves as areophore; the iron is placed in common water. In the porous vessel I place a solution of perchloride of iron with aqua regia added. The electricity of this solution is collected by a carbon serving asthe positive pole. The carbon ig made of powdered coke agglomerated with parafiae. Such a battery may be made of large dimeasions, and’ a great deal of electricity obtained at a smnll cost. Heat has always been supposed to nssist the union of gases which possessed an affinity for each other; but a Frenchman hag found that oxygen has no tendeacy to unite with hydrogen, carbonic oxide or carbou.at a temperature higher than the fusing point of platinum. Tur LARGEST LiriioorAPd ever taken is one of the present French Emperor, which was recently executed on a stoae four feet in width and eight feet in length. “ :

The Mining and Scientific Dress. 15 Ld Mlechanical. ENGLISH OPINIONS. The Eagineering says: " Wo believe onr Yankee brethren make an engine better adapted to rough, aud even to ordinary lincs, than our own, and, on the other side, we consider our engines simpler aud stranger for their work. A. Yaukce hoiler would burst, by hydraulic pressure, long before ours would give way, and yot they carry as high gteam as we.” Mr. Normon Jusse} gays, respecting our beam-cnyines : The American steamboat engino has long heeu a subject of wonder to the Mnglish encinver. tis ugly, straggling, aud inconvenient louking ; its incompactness, nnd want uf snugness and vcououry of room, nuke it the reverse of everything we think good in a steainhoat engine. It aaa made the same impressiun on me that it has done on all my countrymen, but it wns at first sight, and nt rst sight only. Daily the unfavorable impression became titigated hy familiarity, nnd after a carelal study of its details and qualities, { do not think it possihlo to design an eugine more admirubly fit lor its use and purpose, puder the circamstances wheru it is applied. Ja this country there is not a sinvle enzine which can he said to be entirely English, and pre-eminently suited to ony one purpose. The American walking: benm cngine, ou the other hand, ia universal in the States, and ucknowledged to be best suited to thetr Eastern river navigation. I thiok it will be ndmitted, therefore, that the permancnce of this kind of engine in the American stenincrs must be held as prima facie proof of its oxcellence, and that it is entitled to our respectful consideration, and likely to reward our careful study. I have examined the stracture in tho best workshops of America, nod have watched its practical working in their best steamboats. I have sntisficd myself that it.is cheaper in construction, lighter in weight, more economical in management, less costly in repair, wore durahle, and better suited for high speed than any of our own engiues would be. I think that for the navigation of large rivers, like those of China and India, it might he adopted with great advantage, and many of its details, indeed, might he adopted with advantage in any engine. A New Amavcamator.—-There is now being made at the Sacramento Iroa Works, snys the Bee of that city, a newly invented amalgamator, which promises to supersede all others now in use. A miniature edition of this amalgamator has heen in operatiou in that city two or thrce months. It has operated on tailings from Nevada, KE] Dorado, Amador and other miuing counties, aud has never failed to call the cast-off tailiugs to account, advantageously. If the invention possesses all the power which the quartz miners with whom we have conversed claim for it, it isa valuable invention. Ecoxomte Resutts are obtained in burniag fuel, by feeding the fire from below, and thus consuming the fuel from the surfaco downward, instead of trom helow upward, as usaal. ‘T'he air ndmitted ig heated somewhat by the lower strata of fucl before it comes in contact with the hot coals, which assists in a very marked maaner the complete combustion of the carbon. In a puddling furaace, near Glasgow, Scotlnnd, which had consumed 41 ewt. of fuel, only twenty pounds of unburned residue was found. The modifications necessary to carry out this improvement nnder boilers are few and inexpensive, and the results so good that at the Gartness Works, near Glasgow, the weekly returns show a saving of one-third. A Goop Cement.—Gutta percha when dissolved in chloroferm, so as to make a fluid of the consistency of honey, produces a good cement. When spread, it will dry in a few momeats, but it wilksoften by heating. Small patches of leather can he cemcnted on boots hy its use, in such a manner as to almost defy detection, and some shoemakers employ it with great success for this purpose. It is waterproof, resisting all the elemcuts but heat. AN ALLoy consisting of ten parts of casl iron, ten of copper, and eighty of zine, does not adhere to the mold in castiug, and it is of a beautiful luster when filed and polished. The most fractious metals are melted first, and the zine last, in making it. 1 A German, named John A. Heyl, living in Boston, has invented a method lor lighting all the street lamps in a city siineltoneoasly. The lighting of lamps by clectricity is uo new thing, but what Mr. Hleyl claints us the new feature in his inveution isa stop-cock comLined with nn clectric battery, by means of which the operator nt any central point cau tura the gas off or on, at his plensure, at the same tine igniting it with tho clectric battery. ‘the stop-cock is the eriginal leature of the ‘invention, any numberof which can he operated at the same time hy a picce of platina wire. Ju cnsu the wiad Iiluws the gns out, it will ignite nguin of its own accord Irom the heat which is retuined ia the wires, without ony electricity whatever. San Prancrsco as A Masvuvacrurtxa Ciry. lt uppears from nn official statement, compiled froin the ccnsns of 1866, that the city of San Francisco nt that time, although rating as tho fifteenth city in puint of population, stood us high os the ninth in respect to the valuo of her inanufacturing investments and products— a most remarkable showing for a city at that time but eleven years old. Atrn-ITaumers.—Mr. Grimshaw’s high speed Birmingham for voriuus stamping and lorging purposes: at Clasgow for coppersmith’s work, and at Sheffield for steelwork. T'he aachine consists of a force-pump supplying compressed air to a reservoir, and a working cylinder and piston similar to those of a steam-hammer ; having arrangements for varying the action of the hammer as required. aad increasiag the rapidity of the blows, which aay attain a masimum of 800 strokes per minute. The largest hatomer yet put to work las a cylinder 844 in. io diameter, and a stroke of 28 in., and the pressure may be adjusted to any amount from five pounds to forty pounds per square inch. Several steam-hammers of from four to ten hundred weight are working at Sheffield, with which 506 or 600 blows per miaute can be struck if required. Wrovout Iron Drums ror Putieys.—We learn that Messrs. Hudswell & Clarke, of England, are now making a number of drams of wrought iron. ‘The drums are only ahont half the weight of those of cast iron, and by their use the weight upon the bearings of the shafting is much reduced; belts also are found not to slip on them as they do on cast iron drums, ond last much longer; ia fact, at Messrs. Hudswell & Clarke’s own works they state that they have heen enabled to reduce their belt account one-half since they have nsed the wrought-iron drums. Oxsnqur Bruts.—It sometimes happens that it ig necessary to lead a belt obliquely from a pulley or fly-wheel,and iu such cases much trouble is frequently caused by the belt slipping off. ‘This can, in very many instances, be prevented hy fastening a strap of thick leather, of a less width than the belt, around the center of the fly-wheel or pulley. The leather strip may be secured by counter-sunk copper screws passing through it, and tapped into the rim of the wheel.— Engineering. Guy Tunes.—It appears that the steel tubes of the Woolwich guns, although hardened in ofl. will not withstand the action of the powder and the bite of the shot. In many cases the steel tutes have heen deeply scored, and it isa question which, we believe, has been seriously mooted, whether they shall not, in future, be wholly abandoned.—Kngineering. Proressor Anru found that hardened steel wire dissolved in hydrochloric acid without residue, whereas the same steel in the softened state yielded by such actioa a dark flocculeat carbonaceous residue. Pror. Honexinxson has shown that strains, however feeble, if long applied, nroduced some permanent elongation or contraction in bars of iron. Tur Zanesville Courier, in noticing the contemplated visit to that city of Mr. George Peabody, the celebrated London banker, says : * Among the most henevolent deeds of this $50,000 apiece to each of his four nephews in

the East—among them, Mr Arthur Peabody, former local of the Courier.” A. New York city correspondent says that the residence of A. ‘I’. Stewart, corner of Thirty-fourth street and Fifth Avenue, is nearly ready to move into. It eclipses any private huilding on the contiaent, soit is said, and will cost, without aay furniture, $2,500,000. compressed air-hammer is now employed nt ® world renowned hunianitariaa, is the gift of ~— Srientitie Alisccllany. EXTREME DELIOAOY OF PHILOSOPHIOAL INSTRUMENTS. It is wonderful to observe tho great degree of perfection to which nrt has arrived in the constraction of iustruments for philosophicnl purposes. As an evidenco ef this, we may mention a galvanometer, which was manpfnetred a few years since in the city of Berlin for the great Mnglish experimentalist, Julin Yyndetl, F R.S., ete. The galvanometer isan instrument for measuring the furce of the galvanic current. In this iustrumeat two magnetic ucedles are used, ono of whiclt is surrounded by a copper wire, insulated or encased with sik. This wire must bo absolutely pare copper; so delicate is this instrument, tf properly inade, that the least particle of iron in the copper wire will derange its action. In preparing the instruinent above nlluded to, such a derangement was noticcd, although the wire was proved to be absolutely pure. After much rescarch, the derangement was found to exist in the infinitesimally small omount of a compouud of iron used ia the green color of the silk, with which the wire wos coverod! White silk wos substituted, and the derangement disappeared, 7 Again, wo have recorded an instance of a pyroineter, constructed to mensure the degrec of heat transmitted to a piece of iron. The iron employed was an upright bar, two feot long, of sufficient diameter to stand upon its end. A mirror was connected with the top of this bar, from which a beam of light was reflected upon the wall of the room, by an electric lamp. When the bar shortened the mirror turned in one direction; if it lengthened, the mirror turned in the opposite direction. Every movement of the mirror, however slight, was multiplied by a loug index of light, which was made to move through a correspondiag space upon the wall. A mere breath projected agaiast this piece of iron produced a sensible movement of this beam of light. The contact of the flame of a spirit lamp with the iron, caused the index to move throngh a space of fully thirty feet! When it is recollected that this movement of the iadex, was caused by the mere lengthening and contraction of thal bar of iron, due to the small degree of heat applied, some idea may he formed of the delicacy of that mode of observation. Another iustance may be cited: An instrument kaown as‘ Melloni’s Pile,” which is so sensitive as a thermoscope for measuring heat, that it is said to be sensibly affected by the mere warmth of the hand, when held at a distance of six or eight feet from it. PracticaL Science —'Il'yeory anp Fact. In the study of auture two elements come into play, which belong respectively fo the world of sense and to the world of thought. We observe a fact aad seek to refer it to its laws ; weappreheud the law, and seek to make it good in fact. The oae is theory, and the other is experiment or fact; which, when ap plied to the ordinary purposes of life, hecomes practical science. Thus, by the instruction of thought and fact, of truth conceived and truth executed, man bas made science what it is— the noblest growth of modern times. Licuting or Pontic Matis py Maonestun. At the Royal Institution, Loadon, Mr. Larizin recently exhibited bis method of illuminating public halls by the combustion of magnesium. The magnesium, in a finely-divided state, is showered on smat] flames of gas, and thus produces a brilliant illumination. It was the first time the appuratus had heen publicly exhibited. The flame was flickering, hut the pure quality of the light coatrasted strongly with the usnal gas flames of the burners in the lecture theater. Ross, as s00n as the flowers have opened and bloomed one day, should have the decayjug flower cut away; cutting back to a good strovg bud, from which will come a new stem and flowers. Attention to this practice of cutting will keep plauts bloomiag almost continuously. Errects or Lignt ox Leap Patxt.—Dr. D. S. Prico, of the British Asgocintion of Science, having noticed that in the glass cases of the last exhibition at tho Crystal Palace, London, which were pointed with white lead, substunces which emitted sulphurous vapors did uot darken or otherwise effect the paint, except where the paint wns protected from the direct inflnence of the light, was thereby led to make some investigations into the subject. A uumher of expertments were tried, and among others n board was painted with white lead, and sehsequently exposed for several hours to the action of sulphureted hydrogen gas, until the entire surfaco had nequired a dull chocolate culor. Glass of different colors waa then placed upon it, leaving one portion exposed, or withuut any glass, and another portion covered with an opaque medium. The board so prepared was then exposed to the action of light,and several impressions were photographed by the light acting through the glass. Thro glasses employed were red, blue, yellow and violet. he results were that the portions exposed to the light wero bleached, that entirely protected by an opaque covering remained unaltered, whilo correspondingly intermediato effects wero produced by the differently colored glosses, varied according to the different degrees of opaqueness. Nirroteum is a new nomo given to nitroglycerine, by Col. T. P. Shafter, in his late report to the Secretaries of Warand the Navy. The Colonel had been directed to make some comparative tests with gunpowder and nitroglycerine or “nitroleum,” and the report referred to gives the results of these experiments New and Interesting Electrical Experiments. In an account of some electrical experiments reported in Poggeadorff's Annalen, M. Henrici states that if water containing hydrogen in solution be put into comraunication with ordinary water by means of a piece of moist paper, and the circuit be closed by a galvanometer, a current will be produced, directed into the galvanometer, from the ordiaary water to the watcr cbarged with hydrogen. On this fact M. Henrici bases his opiaion that a certain number of phenomena, usually attributed ‘to the action of the oxygen of the air, such as oxydization of iron and other metals, and the putrilaction of vegetable substances, are really due to the decomposition of the atmospheric moisture. Another experiment made by Professor Tait is recorded among the Inte proceediags of the Royal Society of Edinburgh, from which it appears that when a horizoutal plate is put into a state of rapid vibration, iron filiags strewn on the surface, neara point of maxinum vibration, are preveated from being scattered to the nodal lines by n magnetic pole held ahove the plate ; hut if tho pole be held below they are speedily dissipated. If too powerful a pole be used, or if the magaet he held too near the plate, the filings nenrest the pole are not dispersed in the latter case. Profossor Tait thus explains the phenomena : The filings tend to place their greatest length in the direction of lines of magaetic forces; aad thus, when the pole is ahove the plate, their upper ends incline towards it, so that the agitatiun of the platc, combined with the magnetic attraction, brings them nearer to the point immediately below the pole. When the pole is below the plate the upper ends of the filings diverge from the pole, nud the agitation sends them outwards, uuless the nagnetic attractioa be considerable, Cureap Execrricrry.—In a recent note sent to the Academy of Scieaces by M. Gerardia, “Ona Battery of Iron Turnings,” he thus describes the apparatns : “I replace the zinc of a Bunsen's battery by iroa borings; an iron bar placed in the middle of the borings serves as areophore; the iron is placed in common water. In the porous vessel I place a solution of perchloride of iron with aqua regia added. The electricity of this solution is collected by a carbon serving asthe positive pole. The carbon ig made of powdered coke agglomerated with parafiae. Such a battery may be made of large dimeasions, and’ a great deal of electricity obtained at a smnll cost. Heat has always been supposed to nssist the union of gases which possessed an affinity for each other; but a Frenchman hag found that oxygen has no tendeacy to unite with hydrogen, carbonic oxide or carbou.at a temperature higher than the fusing point of platinum. Tur LARGEST LiriioorAPd ever taken is one of the present French Emperor, which was recently executed on a stoae four feet in width and eight feet in length. “ :