Volume 29 (1874) (428 pages)

September 12, 1874. MINING AND SCIENTIFIC PRESS. 168 Scientiric PRocRESs. Veortarion Insine aN Eoo.—A foreign jonrpal states that Prof. Panceri made an interesting commmnnieition to the Institut Egyption at itn mectiug in December, on the cryplogamio vegetation which he bad found within the egg ot an oatrich This egg had been given him at Cairo, and was still fresh, the air space baviug not even been furmed. We oon, however, noticed the nppearunce of dark blotches within the shell, aud huving been broken open to aaceituin the cause, he found that they were prodneed hy the growth of minute fungi. Tustances of a similar kind had already heen studied hy him, and he had communicated tho results to the Bntanival Congross held at Lugano iu 1859, The believers iu the reality of the spontaneous generation of living organisms have not heen slow to seize on these cases as an argnmeut in thoir favor, sines @ priori it wonld acem that the ahell of an egg wonld he gnite impermeuble to germs derived from without. Pancori haa sneeeeded in satisfying himeelf, bowever, that tbe nubroken shelt of an egg is permesble to liquids, nud that theae may introducy geruis into its interior. Ilo hos, iv fnct, actnally succoeded in Inocnlating other eggs with a fnugus which he bad obtained from the interior of one in which it had made its Eeencce in a way apparently so mysterious, Me cnitivated tbe fungus in egg albumen, aud thus conveyed it to the nncontaminated egg. Licnt axn Excraicry.—The English electrician, Willoughby Smith, has receutly discovered a most cnriona action of light in altering the electrical resistance of a metal. In experimenting for a special pnrnose, with some small rods of selenium, abont cne-twentieth of an inch in diameter hy three or fonr inches in length, enclosed in glass tubes, with platinum terminals, he found that their olectrio resistance varied most conspicuously and to a very grent extent. He finally traced tbe disturbance to the action of light—finding that when the rods were enclosed in a dark box their resislance was perfectly normal, while even a slight exposnre to light immediately rednced it some 10 or 15 percent. On bumiing a magnesinm ribhon ata distance of nine iucbes from the asleninm rod, which, to cut off all disturbing action of heat, was immersed in its tuhe toa depth of several inches in a hasin of water, the conductivity of the bar was at once inercased nearly three-fold, remained constant while the light lasted, and as soon as the flame went ont immediately retnrned to its original value. The discovory opens an entirely new field of investigation.--Jour. of Chem. Hynrivum.—This the new name proposed for the metal of which hydrogen gas is considered to he the vapor. There are several reasons for accepting this view; one is that hydrogen hehaves in chemical compounds like a metal; it can replace a metal and be replaced by a metal, according to the law of equivalents, while ‘recently alloys have been made of hydrogen with metals. Graham made the alloy of hydrogen with palladinm, one of the heavy metals, and dedueed from the density of tbe alloy and the amount of hydrogen that it contained that the specific gravity of the latter in this alloyed state of hydrium was 0.62. Recently Troest made the alloy with sodium, one of the light metals, and in the seme way found for the specific gravity of hydrium 0.63. This number ia very near that of lithinm, which is the lightest of all metels, its specific gravity being 0.59.—Manufacturer and Builder. Tar Stppon.—If two vessels are connected at the hottom by a tnbe, the water poured into one of them will rise in both to the same hight, howover different their width and shape may he. If, at the sea shore, a bent tuhe ie led through a dyke, the water will, in the npper part of the tnbe, he on a level with the sea. if a drop of water falls into this tnbe, the whole eea will rise in a proportion diminishing in the ratio of ite greater enrface. This law, of course, holds good for any number of veseely connected by pipee or tubes. An illustration of the application of thie law is furnished by the suterazi of the Turks, who, when deeirous of conducting water from one mountain to another, construct a stone pipe leading from the slope of the former transversely throngh the valley, and then agaiu up tbe slope of the latter. Wuen heat ie applied to a solid, it getwarmer, unti] it hegine to melt. As long as any of the solid remains unmelted, the heat which is continually being poured into it, melts, bnt does not heat it. It does not become sensihle heat, but it changes the state of tbe solid and hecomes, as it ie eometimes called, latent heat. Such heat is called heat of liquefication. Again, the liqnid so ohtained, or another, on receiving the heat, hecomee warmer until the liquid boils. Aslong as any liquid remains, the heat which entore it does not hecome sensible, hut changes the state of the liquid, and issometimee said to he latent in the vapor. Such is heat of vaporisetion. ‘I'he heat of liqnefaction is given ont when tbe vapor condensos. _TuHE modern institution of railroad trains gives us oecasion to oheerve the heat developed by frictional reeistance in the heating of the railroad our axlee, which often hecome so hot that the flame hlezes out of them, setting the oil packing, and occesionally when not noticed, may in time eet the car iteelt’ on fire, Thermometers, The simple principle of the thermometer is that a change in temperature prodneesa change in volume; and upon the nnitormity of this increase depends the acenracy of the instrument. As instruments are usnully made, this is asanmed to he so thronghout their entire range, hut, in reality, this is not the case, cither with a mercurial or spirit thermometer, especially the latter at low temperature, or with either one as the heat approaches the boiling point of . the liqnid, Vor measuring all ordinary ranges of temperature the expansion of niercury is Ko ‘nearly uniform that tne gradnations are made equidistant. If they were divided in accordauco with the expansion of the mercury the spreea for each division would increase from the zero point npward, and deorease from it downward, The freezing and boiliog points are defined for the thermometer by immersion in hoiling water and melting ice, and the space hetween these is then divided into auy urbitrary number of cqual parts, according to the standard desired. In the common lustrumeut, nsed for the ordinary nbservation of temperatnre, the space is divided into 180 eqnal parts, aud is known as the Fubrenheit scule, so named after itsinventor, Iv this instrument the zero point is 32 degrees below tbe freeziug point of water —erroneously so placed hy its inventor, because he snpposed that this was the absoluto zero of temperatnre, Now, since the rate of expausion is not uniform in the tnhe of the thermometer, it follows that the divisions of the seale nre too short from the hoiling point np or down, and too short from the treezing peint up; consequently there can he only one point on the scale ot u thermometer wbich is really accurale, sll the others being only approximate, either ahove or helow the truth. There are yet several other nnavoidable sources of error to he considered. First, the glassin which the merenry is contained also expands and coutracts with the changes of temperature, hnt at a rate corresponding to only one-seventh that of merenry; so tbat, in order to be accnrate, allowance must he made for this, if tbe graduation is made upon the stem of the instrument; if made npon the metal scale to which the glnss is nsnally attached, still another compensation must be made, as expansion of the metal is different from either. Erroneous, therefore, as the measuring of heat must necessarily be by the use of n thermometer, itis yet an instrument of the ntmost 1n1portance to the practical scieutistin every field of investigation and industry. Where very minute ditferences of temperature are to he measnred an instrument called a thermomultiplier is used. This ingenious instrument was brought to such a wonderful degree of perfection by Tyndall that even the differences in the bodily temperature of insects conld he measured, and hy its nse many interestiug and useful discoveries have been made.— Western Manufacturer. YeLLOw Gass For Poorooraraic Purposes. The following simple method of testing the actinic properties of yellow glass for dark rooms is hy Le Neve Foster, and the only apparatus required is a cheap glass prism. When a strip of white paper is placed on p dnl) hlack surface and looked at, throngh the prism, by daylight, it has the appearance of the rainbow, showing a complete spectrum. On bringing the yellow glese in question hetween the prism and the strip of white paper, those colors which are aheorhed by the colored glass disappear. If on looking through the prism any hive or violet rays are seen, it is certain that the glass transmits the chemical raye, and hence is nnfit for photographer’s'nse. If only red and yellow be seen, it is non-actinic. Tae Macnoscopic Examination of Wri Watrr.—Reicha'dt has eought an expeditious method of delermining the quality of drinking water, and recommende the nse of the microscope in detecting ealts in solution by their crystalline form. For thie purpose, a few drops of the water nnder examination are evaporated on a slip of glass either at a high or low temperature, and the forms of crystals ohtained, compsred with those of known ealts diesolved in water, aud réerystellized in the eame manner. In this way one can detect with diepatch and certainty, common salt, cale spar, gypsum, niter, etc., and toa certain extent the relative quantities present. Wit1 17 Work ?—According to the papers M. Michel's ingenione apparatus for indicating automatically the presence of blocke of ice or icebergs ahont shipe ie constrneted as follows: A cese snepended from the side of the ehip encloees a bimetallio thermomcter with a small rod attached to the helix, which moves right or left, according as the temperature rises or falls. Wheu the temperature falls, the rod comes against a emall metallic Enoh, and thus closes a circuit, ringing a bell placed near the officer on watch. : MANUFACTURE, OF Gun Corron. — Samuel Joseph Mackie, Westminster, Englend, claims: ist. The treatment of the vegetable fiber with acids so as to transform it into gnn cotton; the crushing of the fiher so as to destroy its capillary structure and reduce it to an impalpable mass, and the granniatiou of eeid mase. 2d. The production of gun cotton in & moist condition, and the drying of it in vaeno, as sel forth, MecHANicaL (Procress The First Tos! Used by Man. It is interesting to look hackwards aud to find bnw the want of something to aid their natnrul power of mmnscle was first satixfled by the primitive man. The principal tool, jndging by the number of them thut have been found, was the stone hatchet, 1,500 of which were found in one apot in Lake Constanco. In anotuer 96 hatchets, 25 hammera and 25 arrow hends. Thero are 1,070 stone uxes colleoted in the Copenhagen museum, some of which are a foot long, with 824 inches face, made of the toughest flint, which is chipped to a sharp cntting cdge. They were probably tied to a handle of wood or souictimes were inserted in it, judgiug from ths part that is polished by obabng. With the aid of fire this tool seems to have enabled them to cnt down trees of 9 inches diameter. us Many thousand piles, smaller aud up to that aize, are found in the waters of the Swiss lakes with hatchet marks upon them. Besides being of use as weapous in war, they supplied noarly all tho wants of men whose existence soems to heve been spent in finding food and shelter. Accustomed as we are to a tool for every special purpose, so that they are fs nnmerous as our wants, our respected aucestral relatives were forced to content themselves with hnt few in onmber, their trade list consisting mostly of axes, flat chisels, arrow-heads and knives, all made of flint.—Newark MauuSacturer. Agno-Stean Enornes.—Mr, Richard Eaton’s paper on the use of heated air combined with steam in locomotives, read before the British Association, has attracted considerable attention. The principle was invented by Mr. Geo. Warsop, and a stationary engine on this principle was in daily work at tne International Exhibition of 1871. In the case of the locomotive named, an air pnmp, single acting, driven from one of the main cross heads, and secured to the frame work of the engine, in the place originally occupied hy the feed pump, conveys a continuous supply of air, taken from the atmosphere, in its natural state, through a coil of pipes, fixed in the smoke bex, into the hoiler, atan average temperate of ahout 650° Fah. Within the boiler, the heated air is distributed and is continually rising, scattering the cohesion of the molecules of water, increasing the heating snrface, promoting ebnilition, joining the steam on its pasaage to the cylinder, and there greatly aiding the energy of the steam hy retarding condensation, and following a higher curve of expansion. The action of the heated air also prevents a permanent settlemeut of incrusiation on the hoiler, fire bex, or tuhes, entirely ohvintes priming, and diminishes the liahility to explosion. The duration of boiler, tnhes, and fire bex is prolonged by the non-deposit of senle, and steam is more quickly generated and more easily kept np. Izon Cuan Vessris.—The invention of iron plates to protect vessels ia far from heing of ag recent date as ie generally supposed. Dnring the 12th century, the Normans covered their ships from the water-line up with an iron casing, terminating in a ram on the bow. Still earlier they had adopted a system of protecting tho npper worke with metal shields, In 1534 Peter of Arragon ordered his ships to be ironplated, iu order to protect them from the burning missilee then iu common nse. In 1530 the squadron of Andrea Doria contained a vessel built hy the Knights of St. John, which was armored with several thicknesses of iron. At tho hattle of Lepanto, several ships protected their batteries with bers of iron. For two centnries no progress seems to have been made. In 1782, at the siege of Gibraltar, an engineer officer constructed six ehipe, which were the typss of the modern iron-clad. They were covered with an armor of hard wood, leather and bar-iron. It is said that they resisted the fire of the forts for a long period, but were finally snuk by red-hot slot. Economy cr Jnon Cars.—An iron car, made of boiler tin, with a capecity of ten aud a half tons, weighs hut 10,000 pounds, while the wooden car of like capacity will weigh 17,500 ponnde—a difference so great that while 29] loaded iron cars make up a train on the Oumherland and Pennsylvania reilroad, 20 loaded wooden care make up one of equal weight. The iron cers stend the wear and tear of usage hetter than the wooden; come out of a wreck hattered and hent but readily straightened out as well as new, whore wooden ones would be shivered to piecee and bnrnt, and the bolts and bars carried away in a basket. And, moreover, there ie ahout $100 in fivor of the iron car over the wooden when their first oost is considered. Last February, Mr. J.C, Cohnrn, of Worceeter, Massachnsette, patented a soft metal hammer, which is almost indispenseble for vations kinde of work. It has been desigued expressly for that class of work reqniring the nse of a hammor that will prodnce no bruise on the object struck, and it meete this want in a highly setisfactory manner. These hammers are made from one and a half to four pounds in woight, with the head and handle cast ina eingle piece. The hendle is strengthened hy a rod of iron, which runs through the center. How Thimbles are Made. The] wanufactnre of thimbles is very simple, but singularly interesting, aud is described aa followa: Coin silver is mostly nsed, and is obtained by purchasing coiu dollars. Hence it happens that the profits of the hnsiness are affected instantaneously hy all the variations in the nation’s greenhack promise to pay. The first operation strikes a novice as almost wicked, for it is nothing else than pntting a lot of bricht silver dollars, fresh from the mint, into dirty crneibles, and melting tbem up into solid ingots. These are rolled out into the reqnired thicknesa, and cut by a stump into circular pieces of any reqnired size. A solid metal bar of tho size of the inside of the thimble, moved hy powerfnl machinery up and dcwnin a bottomless mold of the outside of the same thimble, henda the circular disks iuto the thimhle shape as fast as they can be placed under the descending bar. Que in shape the work uf brightening, polishing and decoratiug is done npona lathe. Firstthe blank form is fitted npon arapidly revolvingrod. A slight touch of a sharp chisel takes a thin shaving from the end, another does the same on the side, and the third rounds off therim. A ronnd steel rod, dipped in oil and pressed upon the surface, gives it a Instrous polish. Tben a little, revolving steel wheel, whose edge is a raised ornament, held against the revolviug blank, prints that ornament jnst outside the rim. A second wheel prints po different ornament aronnd the center, while a third wheel with sharp poiuts makes the indentations on the lower half end of the thimble. Tbo inside is brightened end polished in a similar way, the thimble being held in a revolvingmold. All that remains to be done is to boil the completed thimbles in soap suds, to remove the oil, brnsh them up, and pack them for the trade. Evropean Onpnance.—All heavy ordnance are now built with steel barrels—this material being fonnd best capable of withstanding erosion from the powder and indentation of the shot. But much divergency occurs in the mode of supporting the barrel hy exterior lnyersof metal. Woolwich obtains support hy coiling renud the steel] harrel hars of wrougbt iron. Vavasseur sppports tbe barrel by shrinking on hoops of eteol, so reguleted that the first layer of honps shall not come into serious operation until the elasticity of the barre) has been developed. Krnpp, who has been gradually assimilatiug his construction to that of Vavassenr, first hy ahandoning hlock steel for the breech, and then abandoning it for the chase, still makes the barrel much thicker at the inner end than is fonnd desirable in this country, and so shrinks on the outer as to cripple the elasti¢ action of the barrel. The French have adopted a system of construction which would he tolerable enough in conversions of old cest iron guns into rifled ordnance of an inferior order, hut is withont any merit hnt cheapnese in new pieces. A steel half-harrel is emhedded in cast iron, and further supported by steel hoops over the powder chamber. By this means the elasticity of the steel half of the barrel is orushed, and a joint with cast iron formed in the interior. Dovsre CaRronomETER BANE Locs.—A few days ago the Stockton Independent noted the fact thatan automaton lock had been placed on the safe of the First National Gold Bank, nnd similar attachments heve heen placed on the safes of the Stockton Savings and Lean Society’e hank, and the San Joaquin Valley hank. The attachment is known as Sergent’s patent, and coneists of two independent clock movements of the most complete and thoroughly huished workmanship. At the time of closing the hank, the movements are sot in a manuer eomewhat similar to that of setting an alarm clock, to open or release a holt at a given hour. The time of opening can be regulated from one to forly-eightfhonrs, The chronometer attachment releases a bolt placed ae additional secur. ity tothe combination lock, and without the release of which the safe or vanlt cennot he opened even hy those possessing the combination. The clock work is made double, so that in case one movement ehould iu any event stop, the other will remove the fastening of the bolt which secures the whole. Gronoz SrerHeEnson, of English origin, the inventor and father of the railway eystem, was the son of a poor miner, and was born in 1781. Blacket, also an Englishman, made the first locom etive to travel on a emooth rail, Stephenson saw this engiue, and decided that he could make a hetter one, and having $4,000 saved, he put it all into the constrnetion of a locomotive, that broke down at the firet trial. His patience and pereeverance, two qnalities requisite in an inventor, did not feil him, and he succeeded in making one of the grandest inventions of all the ages. At onestep of his genius, he quadtnpled the power of the engine, and in that invention he made a etep so gigantic that it can never he forgotten.— Ka, An invention by Siguor Abbiati of a new plow for clearing the tracks of railroade, ie attracting attention, and the claim is made for it that it is both expedilious, thorough and oheap. The machine, which operates on the snow or ice, iea heavy revolving eaw, or fan, whioh cuts into the opposition deeply, and sends the fragments flying. The snow is thrown to 2 great distanca on eithor side, or, in cese of a very steep hank, it is taken up and hurled hackward on platform cars, hy which it can be removed, 5 &

September 12, 1874. MINING AND SCIENTIFIC PRESS. 168 Scientiric PRocRESs. Veortarion Insine aN Eoo.—A foreign jonrpal states that Prof. Panceri made an interesting commmnnieition to the Institut Egyption at itn mectiug in December, on the cryplogamio vegetation which he bad found within the egg ot an oatrich This egg had been given him at Cairo, and was still fresh, the air space baviug not even been furmed. We oon, however, noticed the nppearunce of dark blotches within the shell, aud huving been broken open to aaceituin the cause, he found that they were prodneed hy the growth of minute fungi. Tustances of a similar kind had already heen studied hy him, and he had communicated tho results to the Bntanival Congross held at Lugano iu 1859, The believers iu the reality of the spontaneous generation of living organisms have not heen slow to seize on these cases as an argnmeut in thoir favor, sines @ priori it wonld acem that the ahell of an egg wonld he gnite impermeuble to germs derived from without. Pancori haa sneeeeded in satisfying himeelf, bowever, that tbe nubroken shelt of an egg is permesble to liquids, nud that theae may introducy geruis into its interior. Ilo hos, iv fnct, actnally succoeded in Inocnlating other eggs with a fnugus which he bad obtained from the interior of one in which it had made its Eeencce in a way apparently so mysterious, Me cnitivated tbe fungus in egg albumen, aud thus conveyed it to the nncontaminated egg. Licnt axn Excraicry.—The English electrician, Willoughby Smith, has receutly discovered a most cnriona action of light in altering the electrical resistance of a metal. In experimenting for a special pnrnose, with some small rods of selenium, abont cne-twentieth of an inch in diameter hy three or fonr inches in length, enclosed in glass tubes, with platinum terminals, he found that their olectrio resistance varied most conspicuously and to a very grent extent. He finally traced tbe disturbance to the action of light—finding that when the rods were enclosed in a dark box their resislance was perfectly normal, while even a slight exposnre to light immediately rednced it some 10 or 15 percent. On bumiing a magnesinm ribhon ata distance of nine iucbes from the asleninm rod, which, to cut off all disturbing action of heat, was immersed in its tuhe toa depth of several inches in a hasin of water, the conductivity of the bar was at once inercased nearly three-fold, remained constant while the light lasted, and as soon as the flame went ont immediately retnrned to its original value. The discovory opens an entirely new field of investigation.--Jour. of Chem. Hynrivum.—This the new name proposed for the metal of which hydrogen gas is considered to he the vapor. There are several reasons for accepting this view; one is that hydrogen hehaves in chemical compounds like a metal; it can replace a metal and be replaced by a metal, according to the law of equivalents, while ‘recently alloys have been made of hydrogen with metals. Graham made the alloy of hydrogen with palladinm, one of the heavy metals, and dedueed from the density of tbe alloy and the amount of hydrogen that it contained that the specific gravity of the latter in this alloyed state of hydrium was 0.62. Recently Troest made the alloy with sodium, one of the light metals, and in the seme way found for the specific gravity of hydrium 0.63. This number ia very near that of lithinm, which is the lightest of all metels, its specific gravity being 0.59.—Manufacturer and Builder. Tar Stppon.—If two vessels are connected at the hottom by a tnbe, the water poured into one of them will rise in both to the same hight, howover different their width and shape may he. If, at the sea shore, a bent tuhe ie led through a dyke, the water will, in the npper part of the tnbe, he on a level with the sea. if a drop of water falls into this tnbe, the whole eea will rise in a proportion diminishing in the ratio of ite greater enrface. This law, of course, holds good for any number of veseely connected by pipee or tubes. An illustration of the application of thie law is furnished by the suterazi of the Turks, who, when deeirous of conducting water from one mountain to another, construct a stone pipe leading from the slope of the former transversely throngh the valley, and then agaiu up tbe slope of the latter. Wuen heat ie applied to a solid, it getwarmer, unti] it hegine to melt. As long as any of the solid remains unmelted, the heat which is continually being poured into it, melts, bnt does not heat it. It does not become sensihle heat, but it changes the state of tbe solid and hecomes, as it ie eometimes called, latent heat. Such heat is called heat of liquefication. Again, the liqnid so ohtained, or another, on receiving the heat, hecomee warmer until the liquid boils. Aslong as any liquid remains, the heat which entore it does not hecome sensible, hut changes the state of the liquid, and issometimee said to he latent in the vapor. Such is heat of vaporisetion. ‘I'he heat of liqnefaction is given ont when tbe vapor condensos. _TuHE modern institution of railroad trains gives us oecasion to oheerve the heat developed by frictional reeistance in the heating of the railroad our axlee, which often hecome so hot that the flame hlezes out of them, setting the oil packing, and occesionally when not noticed, may in time eet the car iteelt’ on fire, Thermometers, The simple principle of the thermometer is that a change in temperature prodneesa change in volume; and upon the nnitormity of this increase depends the acenracy of the instrument. As instruments are usnully made, this is asanmed to he so thronghout their entire range, hut, in reality, this is not the case, cither with a mercurial or spirit thermometer, especially the latter at low temperature, or with either one as the heat approaches the boiling point of . the liqnid, Vor measuring all ordinary ranges of temperature the expansion of niercury is Ko ‘nearly uniform that tne gradnations are made equidistant. If they were divided in accordauco with the expansion of the mercury the spreea for each division would increase from the zero point npward, and deorease from it downward, The freezing and boiliog points are defined for the thermometer by immersion in hoiling water and melting ice, and the space hetween these is then divided into auy urbitrary number of cqual parts, according to the standard desired. In the common lustrumeut, nsed for the ordinary nbservation of temperatnre, the space is divided into 180 eqnal parts, aud is known as the Fubrenheit scule, so named after itsinventor, Iv this instrument the zero point is 32 degrees below tbe freeziug point of water —erroneously so placed hy its inventor, because he snpposed that this was the absoluto zero of temperatnre, Now, since the rate of expausion is not uniform in the tnhe of the thermometer, it follows that the divisions of the seale nre too short from the hoiling point np or down, and too short from the treezing peint up; consequently there can he only one point on the scale ot u thermometer wbich is really accurale, sll the others being only approximate, either ahove or helow the truth. There are yet several other nnavoidable sources of error to he considered. First, the glassin which the merenry is contained also expands and coutracts with the changes of temperature, hnt at a rate corresponding to only one-seventh that of merenry; so tbat, in order to be accnrate, allowance must he made for this, if tbe graduation is made upon the stem of the instrument; if made npon the metal scale to which the glnss is nsnally attached, still another compensation must be made, as expansion of the metal is different from either. Erroneous, therefore, as the measuring of heat must necessarily be by the use of n thermometer, itis yet an instrument of the ntmost 1n1portance to the practical scieutistin every field of investigation and industry. Where very minute ditferences of temperature are to he measnred an instrument called a thermomultiplier is used. This ingenious instrument was brought to such a wonderful degree of perfection by Tyndall that even the differences in the bodily temperature of insects conld he measured, and hy its nse many interestiug and useful discoveries have been made.— Western Manufacturer. YeLLOw Gass For Poorooraraic Purposes. The following simple method of testing the actinic properties of yellow glass for dark rooms is hy Le Neve Foster, and the only apparatus required is a cheap glass prism. When a strip of white paper is placed on p dnl) hlack surface and looked at, throngh the prism, by daylight, it has the appearance of the rainbow, showing a complete spectrum. On bringing the yellow glese in question hetween the prism and the strip of white paper, those colors which are aheorhed by the colored glass disappear. If on looking through the prism any hive or violet rays are seen, it is certain that the glass transmits the chemical raye, and hence is nnfit for photographer’s'nse. If only red and yellow be seen, it is non-actinic. Tae Macnoscopic Examination of Wri Watrr.—Reicha'dt has eought an expeditious method of delermining the quality of drinking water, and recommende the nse of the microscope in detecting ealts in solution by their crystalline form. For thie purpose, a few drops of the water nnder examination are evaporated on a slip of glass either at a high or low temperature, and the forms of crystals ohtained, compsred with those of known ealts diesolved in water, aud réerystellized in the eame manner. In this way one can detect with diepatch and certainty, common salt, cale spar, gypsum, niter, etc., and toa certain extent the relative quantities present. Wit1 17 Work ?—According to the papers M. Michel's ingenione apparatus for indicating automatically the presence of blocke of ice or icebergs ahont shipe ie constrneted as follows: A cese snepended from the side of the ehip encloees a bimetallio thermomcter with a small rod attached to the helix, which moves right or left, according as the temperature rises or falls. Wheu the temperature falls, the rod comes against a emall metallic Enoh, and thus closes a circuit, ringing a bell placed near the officer on watch. : MANUFACTURE, OF Gun Corron. — Samuel Joseph Mackie, Westminster, Englend, claims: ist. The treatment of the vegetable fiber with acids so as to transform it into gnn cotton; the crushing of the fiher so as to destroy its capillary structure and reduce it to an impalpable mass, and the granniatiou of eeid

mase. 2d. The production of gun cotton in & moist condition, and the drying of it in vaeno, as sel forth, MecHANicaL (Procress The First Tos! Used by Man. It is interesting to look hackwards aud to find bnw the want of something to aid their natnrul power of mmnscle was first satixfled by the primitive man. The principal tool, jndging by the number of them thut have been found, was the stone hatchet, 1,500 of which were found in one apot in Lake Constanco. In anotuer 96 hatchets, 25 hammera and 25 arrow hends. Thero are 1,070 stone uxes colleoted in the Copenhagen museum, some of which are a foot long, with 824 inches face, made of the toughest flint, which is chipped to a sharp cntting cdge. They were probably tied to a handle of wood or souictimes were inserted in it, judgiug from ths part that is polished by obabng. With the aid of fire this tool seems to have enabled them to cnt down trees of 9 inches diameter. us Many thousand piles, smaller aud up to that aize, are found in the waters of the Swiss lakes with hatchet marks upon them. Besides being of use as weapous in war, they supplied noarly all tho wants of men whose existence soems to heve been spent in finding food and shelter. Accustomed as we are to a tool for every special purpose, so that they are fs nnmerous as our wants, our respected aucestral relatives were forced to content themselves with hnt few in onmber, their trade list consisting mostly of axes, flat chisels, arrow-heads and knives, all made of flint.—Newark MauuSacturer. Agno-Stean Enornes.—Mr, Richard Eaton’s paper on the use of heated air combined with steam in locomotives, read before the British Association, has attracted considerable attention. The principle was invented by Mr. Geo. Warsop, and a stationary engine on this principle was in daily work at tne International Exhibition of 1871. In the case of the locomotive named, an air pnmp, single acting, driven from one of the main cross heads, and secured to the frame work of the engine, in the place originally occupied hy the feed pump, conveys a continuous supply of air, taken from the atmosphere, in its natural state, through a coil of pipes, fixed in the smoke bex, into the hoiler, atan average temperate of ahout 650° Fah. Within the boiler, the heated air is distributed and is continually rising, scattering the cohesion of the molecules of water, increasing the heating snrface, promoting ebnilition, joining the steam on its pasaage to the cylinder, and there greatly aiding the energy of the steam hy retarding condensation, and following a higher curve of expansion. The action of the heated air also prevents a permanent settlemeut of incrusiation on the hoiler, fire bex, or tuhes, entirely ohvintes priming, and diminishes the liahility to explosion. The duration of boiler, tnhes, and fire bex is prolonged by the non-deposit of senle, and steam is more quickly generated and more easily kept np. Izon Cuan Vessris.—The invention of iron plates to protect vessels ia far from heing of ag recent date as ie generally supposed. Dnring the 12th century, the Normans covered their ships from the water-line up with an iron casing, terminating in a ram on the bow. Still earlier they had adopted a system of protecting tho npper worke with metal shields, In 1534 Peter of Arragon ordered his ships to be ironplated, iu order to protect them from the burning missilee then iu common nse. In 1530 the squadron of Andrea Doria contained a vessel built hy the Knights of St. John, which was armored with several thicknesses of iron. At tho hattle of Lepanto, several ships protected their batteries with bers of iron. For two centnries no progress seems to have been made. In 1782, at the siege of Gibraltar, an engineer officer constructed six ehipe, which were the typss of the modern iron-clad. They were covered with an armor of hard wood, leather and bar-iron. It is said that they resisted the fire of the forts for a long period, but were finally snuk by red-hot slot. Economy cr Jnon Cars.—An iron car, made of boiler tin, with a capecity of ten aud a half tons, weighs hut 10,000 pounds, while the wooden car of like capacity will weigh 17,500 ponnde—a difference so great that while 29] loaded iron cars make up a train on the Oumherland and Pennsylvania reilroad, 20 loaded wooden care make up one of equal weight. The iron cers stend the wear and tear of usage hetter than the wooden; come out of a wreck hattered and hent but readily straightened out as well as new, whore wooden ones would be shivered to piecee and bnrnt, and the bolts and bars carried away in a basket. And, moreover, there ie ahout $100 in fivor of the iron car over the wooden when their first oost is considered. Last February, Mr. J.C, Cohnrn, of Worceeter, Massachnsette, patented a soft metal hammer, which is almost indispenseble for vations kinde of work. It has been desigued expressly for that class of work reqniring the nse of a hammor that will prodnce no bruise on the object struck, and it meete this want in a highly setisfactory manner. These hammers are made from one and a half to four pounds in woight, with the head and handle cast ina eingle piece. The hendle is strengthened hy a rod of iron, which runs through the center. How Thimbles are Made. The] wanufactnre of thimbles is very simple, but singularly interesting, aud is described aa followa: Coin silver is mostly nsed, and is obtained by purchasing coiu dollars. Hence it happens that the profits of the hnsiness are affected instantaneously hy all the variations in the nation’s greenhack promise to pay. The first operation strikes a novice as almost wicked, for it is nothing else than pntting a lot of bricht silver dollars, fresh from the mint, into dirty crneibles, and melting tbem up into solid ingots. These are rolled out into the reqnired thicknesa, and cut by a stump into circular pieces of any reqnired size. A solid metal bar of tho size of the inside of the thimble, moved hy powerfnl machinery up and dcwnin a bottomless mold of the outside of the same thimble, henda the circular disks iuto the thimhle shape as fast as they can be placed under the descending bar. Que in shape the work uf brightening, polishing and decoratiug is done npona lathe. Firstthe blank form is fitted npon arapidly revolvingrod. A slight touch of a sharp chisel takes a thin shaving from the end, another does the same on the side, and the third rounds off therim. A ronnd steel rod, dipped in oil and pressed upon the surface, gives it a Instrous polish. Tben a little, revolving steel wheel, whose edge is a raised ornament, held against the revolviug blank, prints that ornament jnst outside the rim. A second wheel prints po different ornament aronnd the center, while a third wheel with sharp poiuts makes the indentations on the lower half end of the thimble. Tbo inside is brightened end polished in a similar way, the thimble being held in a revolvingmold. All that remains to be done is to boil the completed thimbles in soap suds, to remove the oil, brnsh them up, and pack them for the trade. Evropean Onpnance.—All heavy ordnance are now built with steel barrels—this material being fonnd best capable of withstanding erosion from the powder and indentation of the shot. But much divergency occurs in the mode of supporting the barrel hy exterior lnyersof metal. Woolwich obtains support hy coiling renud the steel] harrel hars of wrougbt iron. Vavasseur sppports tbe barrel by shrinking on hoops of eteol, so reguleted that the first layer of honps shall not come into serious operation until the elasticity of the barre) has been developed. Krnpp, who has been gradually assimilatiug his construction to that of Vavassenr, first hy ahandoning hlock steel for the breech, and then abandoning it for the chase, still makes the barrel much thicker at the inner end than is fonnd desirable in this country, and so shrinks on the outer as to cripple the elasti¢ action of the barrel. The French have adopted a system of construction which would he tolerable enough in conversions of old cest iron guns into rifled ordnance of an inferior order, hut is withont any merit hnt cheapnese in new pieces. A steel half-harrel is emhedded in cast iron, and further supported by steel hoops over the powder chamber. By this means the elasticity of the steel half of the barrel is orushed, and a joint with cast iron formed in the interior. Dovsre CaRronomETER BANE Locs.—A few days ago the Stockton Independent noted the fact thatan automaton lock had been placed on the safe of the First National Gold Bank, nnd similar attachments heve heen placed on the safes of the Stockton Savings and Lean Society’e hank, and the San Joaquin Valley hank. The attachment is known as Sergent’s patent, and coneists of two independent clock movements of the most complete and thoroughly huished workmanship. At the time of closing the hank, the movements are sot in a manuer eomewhat similar to that of setting an alarm clock, to open or release a holt at a given hour. The time of opening can be regulated from one to forly-eightfhonrs, The chronometer attachment releases a bolt placed ae additional secur. ity tothe combination lock, and without the release of which the safe or vanlt cennot he opened even hy those possessing the combination. The clock work is made double, so that in case one movement ehould iu any event stop, the other will remove the fastening of the bolt which secures the whole. Gronoz SrerHeEnson, of English origin, the inventor and father of the railway eystem, was the son of a poor miner, and was born in 1781. Blacket, also an Englishman, made the first locom etive to travel on a emooth rail, Stephenson saw this engiue, and decided that he could make a hetter one, and having $4,000 saved, he put it all into the constrnetion of a locomotive, that broke down at the firet trial. His patience and pereeverance, two qnalities requisite in an inventor, did not feil him, and he succeeded in making one of the grandest inventions of all the ages. At onestep of his genius, he quadtnpled the power of the engine, and in that invention he made a etep so gigantic that it can never he forgotten.— Ka, An invention by Siguor Abbiati of a new plow for clearing the tracks of railroade, ie attracting attention, and the claim is made for it that it is both expedilious, thorough and oheap. The machine, which operates on the snow or ice, iea heavy revolving eaw, or fan, whioh cuts into the opposition deeply, and sends the fragments flying. The snow is thrown to 2 great distanca on eithor side, or, in cese of a very steep hank, it is taken up and hurled hackward on platform cars, hy which it can be removed, 5 &