Volume 28 (1874) (430 pages)

February 7, 1874.] MINING AND SCIENTIFIC PRESS. 83 §cientiFic (PRoGREss. Enameling Paint. One of the most recent inventions for painting or coating surfaces is a new paint bronght out by Mr. Griffiths of Liverpool; which bas, according to the Furnifure Gazette, tho property of forming a firm, impenctriblo enamel on the snrface of the article to which it is appliod. By this means, the surface is reudered absoIntely water-proof, however porona it may he. The niaterial is coneeqnently intended, not ouly for decorative pnrposos, bnt to be applicd as a water-proof coating to the walls or fonndations of dwelling-honses, railway arches, hridges, tuanels, viaducts, and other structures of brick, plaster, wood or iron. It is also stated that the paint is well adapted for covering the bottoms of vessels, or snhmerged xtructnres of any description. Various trials have at different times been made of it. At Portobello it was tried on some iron plates, aud theee were immersed for three months in sea-water. At the expiration of that time the plates were taken up and examined, when it waa found that they looked fresh and clean as ever, and qaite free from senweed; and, on somo of the enamel being scraped off, the metal ehowed no signs of rust, althongh similar plates, treated with othor kinds of paiut, and immersed in the samo way, were both fonl and greatly oxidized. Asa second test, some of this paint was applied to the steamers tradiag to Africa from Liverpool, and these also showed no eigns of corrosion on tbeir retnrn. It is also said that its smooth surface gives it considerable sanitary value, and for this reason, as well as that it defies the attacks of white ants, the buts used for the soldiers in the Ashantee expedition are to be coated with it. The walls of the huts, which the paint will make smootb, and polished like glase, can be washed with soap and water, or disiufecting fluid. This enamel is also available for painting the walls of hospitals, fever wards, etc., as the porosity of the plaster is entirely etopped, thns preventing infection from lodging. It can be made of any color. White aud chocolate are generally used. Various processes for the preservation of ships’ bottoms from fonling have, from time to time, heen bronght before the public, and the patents on the subject are very nnmerous. The earliest of these was taken ont in 1695, (No. 341), by Charles Ardesoif, for “A new inverted composicion, which will preserve ehips from the worms, insoemuch that any ship may, by virtne of the same, continne at sea for fonr or five yeares without receiving any damage from tbe worms.”’ Since that time very varions methods have been employed, with greater or less saccess. The chief merit claimed by Mr. Griffiths for hisinvention, is that of simplicity of application, as it is simply spread on with a brnsh, like common paint, and sets qnite firm in abont an honr, even on wet surfece. Snch descriptions are certainly very iuviting, but we confess, that by dint of constant reiteration, snd breaking of similar promises, nsually made by interested parties, we have become somewhat skeptical. We are not told what is the composition of the new paint—we presnme it to be an adaptation of slate dust, or of solnble gless—these have both been long used, and in maay cases with good results. But Mr. Griffiths’ psipt is entirely too good. TempeuIna STeeL ann REOENERATING Burnt Tnon.—M. H. Caron says: A piece of steel is generally tempered, and then reheated more or less according to the hardness and the elasticity which it requires to receive. The dry temper, commonly practiced, that is to say, plunging the red-hot metal into cold water, has the drawback of developing cracks and crevices injurions to its tenacity, Reheating does not remove these flaws; and subsequently, on nse, these fissnres, though invisible at first, increase and terminate in fractures. It has already been disoovered that, in order to escape danger, it is preferable to temper the steel a little eofter and afterwards to reheat more elightly. The author hae eucceeded in prodncing the combined effeo‘e of temper and reheating in one operation, and of removing as far ae possible the chances of flawa. This is done by heating the water, into which the red-hot metel is plunged, to 559, Tempering in hot, or even boiling, water, modifiee soft steel containing from two to fonr thousaudths of carbon. Thie proceea aagments its tenacity and elasticity without eensibly altering its softness. The texture is changed and becomes fibrons, even if previously crystalline. The method for restoring burut metal is likewise to plunge it at a red heat into a hot liqnid. Asmronio SuLpaate.—L. L. Hote proposes to ntilize refuse wool, horn, feathere, and other nitrogenons bodies by digesting them with a dilute solution of canstic soda, 1 part soda to 10 of water, uutil they have assumed a paety consistency. The mass ie then mixed with quicklime and distilled, at first at a low heat and afterwarde at a fnll red. The vapore are condeneed in chamber acid. The residuum in the retort is carbonate of soda and quioklime. By hoiling thie with water the aoda is recovered as cauetic soda, and ie ready for the next operation, Action or pitctx Sorctioxs or Sarts on zxan.—The following points, made by P. Moir, will he fonnd of interest, in sequence to articles Intely published by us in relation to purity of driuking water, ete.: 1. A nitrate, and particnlarly annnonium aitrate, increases the solvent power of water for lead more than aay other salt experimented with. 2. Small quantities of nitrates seem to increase this solvent power nearly as much as larger quantities, A lilre of water contniaiug .02 grm. nf a nitrate, was fonnd to dissolve uearly os much lead iu a given time as deuble the quantity of sult. 8. Chlorides, at least calcium: chloride, do uot increase, hut ratber diminish the action of water ou lead, and that, too, when the water contains a nitrate. 4. Carhonates diiuiaish the action of water on lead moro than other salts. Onc purt of potaesium carbonate in three thonsand parts of wator will prevent almost entirely the action of water on lead. 5. Sulphatos behave like carbouates, thongh they are not quite as effectual in their action as carbonates. 6. Water containing a nitrate, and at the same time a carbcuate and a sulphate, will have but little, if any, action on teed. rl Foca Dirveugnces in THE Exes.—A writer in Science Gossip speaks of the difliculty which some persons experience in thense of binocular microscopes, owing to a focal difference in the eyes. In a case mentioned one eye was fareighted, while the other was near-sighted. For reading purposes, this person wears a pair of spectacles in which the one glass is made for the far sight, while the other is a plain glass, the left eye being near-sighted, and coasequently requiring no aid from spectacles with which to read. Instances are cited of persons who, while employing both eyes for ordinary vieion, nsnally employ only one in reading. If any difference of the kind exists between the visual power of a pair of eyes, it may bereadily detected. Hold up a piece of eard hefore one eye, 80 a8 to cut off its field of view, and then look at aome object before yon with the other. Then gradnally bring the card before the other eye, and view the same object. If the object ls seen with the same distinctness in each ease, theu yonr eyes are perfect as regards the balance of their foci; if not, then there is focal difference more or less decided. It weuld uo donbt be advisable to take account of this very frequent difference of focns, in selecting a pair of spectacles, ANaLyticat Pnooress.—In search of, a method of determining the elements of organic substances hy a single combustion, Mitscherlich hss recently discovered a new mode by which, by direct anelysis, not only the carbon, oxygen and hydrogen in an organic substance ean he determined, hunt also the oblorine, hromine, sulphur, iodine, phosphorus, and probably also the nitrogen therein contained. The organic material is brought to combnstion with oxide of mercury, the results of which process are water, carbonic acid and mercury. The two former are weighed in the ordinary manner. The weight of the mercury formed serves to determine the qnantity of oxygen due to combnstion, by subtracting which from that contained in the carbonic acid and the water, the total amount of oxygen existing in the substance submitted to elementary analysis is fonnd. If, however, the body under examination contains chloriae, hromine, or iodine, these elements combine with the mercury set free, and are determined by weighing. Sulphur and phosphorus combine in the state of sniphate and phosphate of oxide of mereury. Zine SMELTING. By a new process, the ore, mixed with carbonsceous powder, is placed in a heated oveu situated over a furnace charged with coke or other carbeuaceous matter. This furnece is snpplied with air nreferably heated in such limited quantity as to generate carbonie oxide, which is led hot through the oven above. The ore is thus reduced, and zinc vapor is carried by the gases through exposed passages, wherein it is condensed and from the hottoms of which liquid zinc flows. The condensation of the zinoie aided by keeping the gaees under pressure, which is effected by forcing air into the generating furnace and making the gasee, at their final escape, pase a loaded valve. In escaping, the gases bubble throuh water, wherehy any portione of zinc vapor are condensed, and they may then be led to a boiler or other furnace, where such conbustible ingredients as they may contain an be utilized as fnel. SepanaTIONn oF Zine, CopaLr ann Nroxen.— We find the following method given in Iron: The three metals are brought into the shape of chlorides and then mixed with ammonic chloride, evaporated to dryness, and then gently ignited. The chloride of zinc will be volatilized. The nickel and cobalt may then be eeparated by meane of potassic nitrite in the usual manner. Erreert or Execorsrcity on Heaten Sree t.— MM. Treve and Chedeville find that if a current of electricity traverses a coil of wire that eurrounds a cooling ingot of cast eteel, the steel, wheu perfeotly cold, shows on fracture a finer grain than when thecurrent ie not passed. The magnetized steel also had lese power of resisting forces of extension and compression. MECHANICAL ‘PROGRESS A New Type-Setting Machine. The art of printing hy machinery has advanced witb very rapid strides during tho last twenty years; 30 qnickly, indeed, that the variety of machines at present in use is scarcely kuown even te printere’ eugineers. But this only applies to tbe printing-presas department, or that division of the trade which impresees tbe types on the paper after they have been put together into pages and locked innn iron framo termed a ‘* chasc.”’ Strauge to eay, notwithstanding all these improveinents in the printing-off of the “formes” of type, the art of the compoeilor—the man who puta the typo togeth«c r —bas been left where it was above two centuriesago. But this has not ariseu either from oversight or from a belief that the art had arrived at perfectiou, but from the inuamerable difficnlties which attend the application of machinery to somposiag. For fifty years failnre has followed the footsteps of inventore. notwithstanding their partia] success, mainly of late yeare, hecanse the advantage gained by machinery over men was too small to pay for repairs and retnrn a decent interest ou the original cost of the machine. ‘he cariest of these machines was that produced by Dr. Chnrch just fifty yesrs ago, the latest hefore the geueral public wae that shown at work in the Exhibition of 1872, and which it was remarked by strangere to the art of printlng was constantly gettiag out of order. In uext year’s Exhibition, however, we hope to see a new one whieh will find more favor with master printers than its predecessore, as it is constructed on an entirely original plan, and cannot easily be deranged, or if deranged by a vice, can be put in order ina few seconds. The machine has not yet been patented, but we have been favored witha sight of it at work, when it gave very satisfactory results. This machine is the invention of Mr. J. Hooker, 2 compositor aud self-taught mechanic, who has bad cousiderable experience in the working of type setting and distributing machines, and consequently has had a capital opportunity of testing their value and observing their defects. Besides the above, the inventor is now constructiug its sister machine—a distrihutor—without which the art of composing is not considered complete; bnt at the time of our visit, this machine was so little advanced that we conld not test its valne or detect its defects. The composiug machine can be worked singly—that is, by one man—but ,the inventor tells us that it is most economically worked by three men and a boy, who can produce werk equal to that of twelve compositors, and with many less errors, which we believe is in the limit of its power, as we tested the speed and worked it onrselves. The inventor has been during that time twice abandoned a partly completed machine for improved ones on new principles. He has studied every English patent, and has done wisely in constructing a perfect machine instead of patenting a model, which can never show whether an invention can be pecuuiarily successful or not. For his sake, and asa boon to the newspaper and reading public, we wish him every success.—Jron, A Noven Borerar Derecror.~The Montreat Gazette recently informed us that “the profession of burglary, at all times a hazardous pursuit, is likely to become still more dangerous to its followers in the fntnre—thanks to an ingenious invention which was privately exhibited at the Mechanics’ Hall. We allude to Simpsou’s ‘Excelsior Burglar Detector,’ which is an apparatus of great simplicity, and one whioh will no doubt answer all the purposes for which it is designed. It consists of a small cast-iron block, haviug fonr chamhers drilled in the surface, commuaication between which is managed by a fuse hole rnaning from the bottom of the fourth to the first hole. These holes are chsrged with powder, ordinary gun wadding being used, and exploded by means of a strong hammer spring, which, being connected with wiree to any part requiring proteotion, is brought down on the uipple by the slightest touch of the wire. The firstchamber is thus exploded, and after an elapse of a few secoads the other chambers explode in euccession, owiag to the fuse at the bottom, giving an alarm loud enongh to awaken Rip Van Winkle or put a regiment of burglars to flight. Ae mauy connecting wires can be used ae suit the owner’e fancy, aud if he is inclined to inflict punishment upon the intruders, all that is necessery ie to have the chambere loadod with ball, with the muzzles pointed in the direction from whence he anticipates a visit. The apparatus je certainly a very nseful and effective one, and, must be exteneively nsed by those householders who desire to protect their property from burglars.”’ APPLICATION OF THE Sann-Buast.—The most recent application of the eand-blast is for cleaning the fronts of huildinge by removing the soot, dust, and other substances therefrom. The impact of the sand on the eurface removes the soot or dust from all the crevicesand indentatione, without perceptibly interfering with the eharpness of the architeatural ornamenta£ a ER Soe. Arts, Sixotk-aam Rarpway.—In a late issno we described 2 novel plan, receatly put in operation in Georgia, by which locomotivo aud care would require only a eiugle rail. An English exchange thus comments ou it; As the railway develops, ite proportions contract. The wido gange of six and eeven feet bas dwindled hy tnrns to the narrow gaage of 4ft. 8in., to tho weter gange of 3914 in., to the Islo of Mau gauge of three fect, to the talked-abont 33 inch, and to the really executed two-feet Festiniog. The last-meutioued narrow gauges have becu completely ontdone by the ‘‘prismoid, or onetrack railway,'’ recently constructed at Atalanta, Georgia. This is built np of severel tbickuesses of plank and is saidto resemble tho "inverted keel of a vessel with a flat railon the apex.’ A railway track of this kiad can he bailt at tbe cost of three thousand dollars per mile. The engine is a four-ton locomotive, or stesm bicycle, which is fitted with flanges on tho ontside of each wheel, locking, itis said, the rolling stoek tothe prism. Vhisis probably very woll enited for a street railroad in Atalanta, or any other fastly-named place that is not ina horry. No doubt it wenld run, aftera fashion, hut the difference in the amonnt of friction incurred hy the varions parte of the broad flauge would alone disqualify the invention from any elaim to practical utility. Something prismoidal was, if we mistake not, tried on the Semniering some years ago, with the view of snrmounting the difficulties of a steen gradieat, but was abandoned on account of unequal friction. No high rate of speed can be ohtained by ‘‘fancy’’ machines made in defizace of wellknown laws, and, althongh it may be amusing to many to see the railway rednced to its lowest terms, the experiment will prove far more carious than neetnl. How Mirnors aaz Siiveavn.—The following description of ‘*’silvering '’ plate glass for mirrors is mainly founded upon the method pureued al St. Gobiu and Raveuhead. After polishing, each glase tablet intended to make a lookiag-glass is silvered, or, more oorrectly, coated on one side with an amalgam of tin. In the preparation of this amalgam tiatoil is nsed, but it mnst he beaten from the finest tin, and possess a sprface similar to that of polished silver. ‘The art of silvering is simple, and merely requires dexterity. The glass plate having been thoronghly cleansed from all gresse and dirt with putty-powder and wood ash, the workman proceeds to lay a sheet of tinfoil smoothly upou the table, carefully pressiag out with a cloth dabber all wrinkles and places likely to form air bubbles. He spreads over it a quantity of mercury, taking cere that all parts are equally covered. and then the glass plate is pushed gently on to the surface, commencing at one edge. The glass is allowed to remain for twenty-four honrs; it is then removed to a wooden incliue similar to a reading-desk, to allow of the excess of mercury draining off. As the amalgam gradually sets, the incline is increased till finally the plate reaches the perpendicular, when the process isifinished, and the mirror removed to -the store-room. over ten years working ont his ideas, and has . “Iyrpuoven’’ MzTHOD oF PropenirNo Beats, ---We notice the following description of a propelling apparatns in general circnlation. We recollect having seen already sevezal models of this most valuable idea, and do not nnderstand how it can be patentahle: To the bar or lever of the paddle are hingedtwo blades in sucha way that when moviag forward through the water the pressure of the water will close them. These are kept from closing against each other by one or more stops, interposed between them and attached to the bar, so that as the paddle begins to make the stroke the pressure of the water may open or spread the-bladea so as to present the greatest possible snrface. The upper ends of the bsr are designed to be attached to the shafts, which are arrauged so as to he operated independently of esch other. The shafts are placed in line with each other, and a;pintel may be attached to the end of one shaft to enter a socket inthe end of the other shaft. Levers are attached to the iuner parts of the shafts, extending above and below said shafts, and having handles attached to theirjnpper ends and foot.rests attached to their lower ends, so that the operator cen apply hand and foot power. Tue ARTILLERY OF THE PEaton.—The monster weapone with which the turrets of the ironclads of the futnre will he armed, will far surpass the most powerful artillery at present in existence, the Woolwich Infante of 35 tons weight, and a bore of 12 in. in diameter, and the greet guns which Krupp is now making for the Germans being alike eclipsed hy the new weapon, which will have a bore of nearly 15 in., aud weigh 60 tons. These guns will be built by coil upon coil of wrought-iron and a eteel tnbe; a aystem which inenres the greatest poasible atrength and immnnity from danger of hnrsting, and practicelly imposes no limit to the size of the guns. They will be fitted with a movable hreech-loading arraagement. The Woolwich Infant will throw a 700 pound ehot six or eeven miles: the new gun will hurl a projectile weighing 1,100 pounds, (half a ton), over a range which has yet to be determined. As the antitheeie of this enormons gnn, the new eteel mountain gun has now heen placed in the model room of the Royal Gun Factories. The gun weighs only 200 ponnds, hut it can fire a ehell of 7 pounds, with good effect, up to 3,000 yards, and with its little carriage is designed to he conveyed on the hacks of mulee, — Iron Monger.

February 7, 1874.] MINING AND SCIENTIFIC PRESS. 83 §cientiFic (PRoGREss. Enameling Paint. One of the most recent inventions for painting or coating surfaces is a new paint bronght out by Mr. Griffiths of Liverpool; which bas, according to the Furnifure Gazette, tho property of forming a firm, impenctriblo enamel on the snrface of the article to which it is appliod. By this means, the surface is reudered absoIntely water-proof, however porona it may he. The niaterial is coneeqnently intended, not ouly for decorative pnrposos, bnt to be applicd as a water-proof coating to the walls or fonndations of dwelling-honses, railway arches, hridges, tuanels, viaducts, and other structures of brick, plaster, wood or iron. It is also stated that the paint is well adapted for covering the bottoms of vessels, or snhmerged xtructnres of any description. Various trials have at different times been made of it. At Portobello it was tried on some iron plates, aud theee were immersed for three months in sea-water. At the expiration of that time the plates were taken up and examined, when it waa found that they looked fresh and clean as ever, and qaite free from senweed; and, on somo of the enamel being scraped off, the metal ehowed no signs of rust, althongh similar plates, treated with othor kinds of paiut, and immersed in the samo way, were both fonl and greatly oxidized. Asa second test, some of this paint was applied to the steamers tradiag to Africa from Liverpool, and these also showed no eigns of corrosion on tbeir retnrn. It is also said that its smooth surface gives it considerable sanitary value, and for this reason, as well as that it defies the attacks of white ants, the buts used for the soldiers in the Ashantee expedition are to be coated with it. The walls of the huts, which the paint will make smootb, and polished like glase, can be washed with soap and water, or disiufecting fluid. This enamel is also available for painting the walls of hospitals, fever wards, etc., as the porosity of the plaster is entirely etopped, thns preventing infection from lodging. It can be made of any color. White aud chocolate are generally used. Various processes for the preservation of ships’ bottoms from fonling have, from time to time, heen bronght before the public, and the patents on the subject are very nnmerous. The earliest of these was taken ont in 1695, (No. 341), by Charles Ardesoif, for “A new inverted composicion, which will preserve ehips from the worms, insoemuch that any ship may, by virtne of the same, continne at sea for fonr or five yeares without receiving any damage from tbe worms.”’ Since that time very varions methods have been employed, with greater or less saccess. The chief merit claimed by Mr. Griffiths for hisinvention, is that of simplicity of application, as it is simply spread on with a brnsh, like common paint, and sets qnite firm in abont an honr, even on wet surfece. Snch descriptions are certainly very iuviting, but we confess, that by dint of constant reiteration, snd breaking of similar promises, nsually made by interested parties, we have become somewhat skeptical. We are not told what is the composition of the new paint—we presnme it to be an adaptation of slate dust, or of solnble gless—these have both been long used, and in maay cases with good results. But Mr. Griffiths’ psipt is entirely too good. TempeuIna STeeL ann REOENERATING Burnt Tnon.—M. H. Caron says: A piece of steel is generally tempered, and then reheated more or less according to the hardness and the elasticity which it requires to receive. The dry temper, commonly practiced, that is to say, plunging the red-hot metal into cold water, has the drawback of developing cracks and crevices injurions to its tenacity, Reheating does not remove these flaws; and subsequently, on nse, these fissnres, though invisible at first, increase and terminate in fractures. It has already been disoovered that, in order to escape danger, it is preferable to temper the steel a little eofter and afterwards to reheat more elightly. The author hae eucceeded in prodncing the combined effeo‘e of temper and reheating in one operation, and of removing as far ae possible the chances of flawa. This is done by heating the water, into which the red-hot metel is plunged, to 559, Tempering in hot, or even boiling, water, modifiee soft steel containing from two to fonr thousaudths of carbon. Thie proceea aagments its tenacity and elasticity without eensibly altering its softness. The texture is changed and becomes fibrons, even if previously crystalline. The method for restoring burut metal is likewise to plunge it at a red heat into a hot liqnid. Asmronio SuLpaate.—L. L. Hote proposes to ntilize refuse wool, horn, feathere, and other nitrogenons bodies by digesting them with a dilute solution of canstic soda, 1 part soda to 10 of water, uutil they have assumed a paety consistency. The mass ie then mixed with quicklime and distilled, at first at a low heat and afterwarde at a fnll red. The vapore are condeneed in chamber acid. The residuum in the retort is carbonate of soda and quioklime. By hoiling thie with water the aoda is recovered as cauetic soda, and ie ready for the next operation, Action or pitctx Sorctioxs or Sarts on zxan.—The following points, made by P. Moir, will he fonnd of interest, in sequence to articles Intely published by us in relation to purity of driuking water, ete.: 1. A nitrate, and particnlarly annnonium aitrate, increases the solvent power of water for lead more than aay other salt experimented with. 2. Small quantities of nitrates seem to increase this solvent power nearly as much as larger quantities, A lilre of water contniaiug .02 grm. nf a nitrate, was fonnd to dissolve uearly os much lead iu a given time as deuble the quantity of sult. 8. Chlorides, at least calcium: chloride, do uot increase, hut ratber diminish the action of water ou lead, and that, too, when the water contains a nitrate. 4. Carhonates diiuiaish the action of water on lead moro than other salts. Onc purt of potaesium carbonate in three thonsand parts of wator will prevent almost entirely the action of water on lead. 5. Sulphatos behave like carbouates, thongh they are not quite as effectual in their action as carbonates. 6. Water containing a nitrate, and at the same time a carbcuate and a sulphate, will have but little, if any, action on teed. rl Foca Dirveugnces in THE Exes.—A writer in Science Gossip speaks of the difliculty which some persons experience in thense of binocular microscopes, owing to a focal difference in the eyes. In a case mentioned one eye was fareighted, while the other was near-sighted. For reading purposes, this person wears a pair of spectacles in which the one glass is made for the far sight, while the other is a plain glass, the left eye being near-sighted, and coasequently requiring no aid from spectacles with which to read. Instances are cited of persons who, while employing both eyes for ordinary vieion, nsnally employ only one in reading. If any difference of the kind exists between the visual power of a pair of eyes, it may bereadily detected. Hold up a piece of eard hefore one eye, 80 a8 to cut off its field of view, and then look at aome object before yon with the other. Then gradnally bring the card before the other eye, and view the same object. If the object ls seen with the same distinctness in each ease, theu yonr eyes are perfect as regards the balance of their foci; if not, then there is focal difference more or less decided. It weuld uo donbt be advisable to take account of this very frequent difference of focns, in selecting a pair of spectacles, ANaLyticat Pnooress.—In search of, a method of determining the elements of organic substances hy a single combustion, Mitscherlich hss recently discovered a new mode by which, by direct anelysis, not only the carbon, oxygen and hydrogen in an organic substance ean he determined, hunt also the oblorine, hromine, sulphur, iodine, phosphorus, and probably also the nitrogen therein contained. The organic material is brought to combnstion with oxide of mercury, the results of which process are water, carbonic acid and mercury. The two former are weighed in the ordinary manner. The weight of the mercury formed serves to determine the qnantity of oxygen due to combnstion, by subtracting which from that contained in the carbonic acid and the water, the total amount of oxygen existing in the substance submitted to elementary analysis is fonnd. If, however, the body under examination contains chloriae, hromine, or iodine, these elements combine with the mercury set free, and are determined by weighing. Sulphur and phosphorus combine in the state of sniphate and phosphate of oxide of mereury. Zine SMELTING. By a new process, the ore, mixed with carbonsceous powder, is placed in a heated oveu situated over a furnace charged with coke or other carbeuaceous matter. This furnece is snpplied with air nreferably heated in such limited quantity as to generate carbonie oxide, which is led hot through the oven above. The ore is thus reduced, and zinc vapor is carried by the gases through exposed passages, wherein it is condensed and from the hottoms of which liquid zinc flows. The condensation of the zinoie aided by keeping the gaees under pressure, which is effected by forcing air into the generating furnace and making the gasee, at their final escape, pase a loaded valve. In escaping, the gases bubble throuh water, wherehy any portione of zinc vapor are condensed, and they may then be led to a boiler or other furnace, where such conbustible ingredients as they may contain an be utilized as fnel. SepanaTIONn oF Zine, CopaLr ann Nroxen.— We find the following method given in Iron: The three metals are brought into the shape of chlorides and then mixed with ammonic chloride, evaporated to dryness, and then gently ignited. The chloride of zinc will be volatilized. The nickel and cobalt may then be eeparated by meane of potassic nitrite in the usual manner. Erreert or Execorsrcity on Heaten Sree t.— MM. Treve and Chedeville find that if a current of electricity traverses a coil of wire that eurrounds a cooling ingot of cast eteel, the steel, wheu perfeotly cold, shows on fracture a finer grain than when thecurrent ie not passed.

The magnetized steel also had lese power of resisting forces of extension and compression. MECHANICAL ‘PROGRESS A New Type-Setting Machine. The art of printing hy machinery has advanced witb very rapid strides during tho last twenty years; 30 qnickly, indeed, that the variety of machines at present in use is scarcely kuown even te printere’ eugineers. But this only applies to tbe printing-presas department, or that division of the trade which impresees tbe types on the paper after they have been put together into pages and locked innn iron framo termed a ‘* chasc.”’ Strauge to eay, notwithstanding all these improveinents in the printing-off of the “formes” of type, the art of the compoeilor—the man who puta the typo togeth«c r —bas been left where it was above two centuriesago. But this has not ariseu either from oversight or from a belief that the art had arrived at perfectiou, but from the inuamerable difficnlties which attend the application of machinery to somposiag. For fifty years failnre has followed the footsteps of inventore. notwithstanding their partia] success, mainly of late yeare, hecanse the advantage gained by machinery over men was too small to pay for repairs and retnrn a decent interest ou the original cost of the machine. ‘he cariest of these machines was that produced by Dr. Chnrch just fifty yesrs ago, the latest hefore the geueral public wae that shown at work in the Exhibition of 1872, and which it was remarked by strangere to the art of printlng was constantly gettiag out of order. In uext year’s Exhibition, however, we hope to see a new one whieh will find more favor with master printers than its predecessore, as it is constructed on an entirely original plan, and cannot easily be deranged, or if deranged by a vice, can be put in order ina few seconds. The machine has not yet been patented, but we have been favored witha sight of it at work, when it gave very satisfactory results. This machine is the invention of Mr. J. Hooker, 2 compositor aud self-taught mechanic, who has bad cousiderable experience in the working of type setting and distributing machines, and consequently has had a capital opportunity of testing their value and observing their defects. Besides the above, the inventor is now constructiug its sister machine—a distrihutor—without which the art of composing is not considered complete; bnt at the time of our visit, this machine was so little advanced that we conld not test its valne or detect its defects. The composiug machine can be worked singly—that is, by one man—but ,the inventor tells us that it is most economically worked by three men and a boy, who can produce werk equal to that of twelve compositors, and with many less errors, which we believe is in the limit of its power, as we tested the speed and worked it onrselves. The inventor has been during that time twice abandoned a partly completed machine for improved ones on new principles. He has studied every English patent, and has done wisely in constructing a perfect machine instead of patenting a model, which can never show whether an invention can be pecuuiarily successful or not. For his sake, and asa boon to the newspaper and reading public, we wish him every success.—Jron, A Noven Borerar Derecror.~The Montreat Gazette recently informed us that “the profession of burglary, at all times a hazardous pursuit, is likely to become still more dangerous to its followers in the fntnre—thanks to an ingenious invention which was privately exhibited at the Mechanics’ Hall. We allude to Simpsou’s ‘Excelsior Burglar Detector,’ which is an apparatus of great simplicity, and one whioh will no doubt answer all the purposes for which it is designed. It consists of a small cast-iron block, haviug fonr chamhers drilled in the surface, commuaication between which is managed by a fuse hole rnaning from the bottom of the fourth to the first hole. These holes are chsrged with powder, ordinary gun wadding being used, and exploded by means of a strong hammer spring, which, being connected with wiree to any part requiring proteotion, is brought down on the uipple by the slightest touch of the wire. The firstchamber is thus exploded, and after an elapse of a few secoads the other chambers explode in euccession, owiag to the fuse at the bottom, giving an alarm loud enongh to awaken Rip Van Winkle or put a regiment of burglars to flight. Ae mauy connecting wires can be used ae suit the owner’e fancy, aud if he is inclined to inflict punishment upon the intruders, all that is necessery ie to have the chambere loadod with ball, with the muzzles pointed in the direction from whence he anticipates a visit. The apparatus je certainly a very nseful and effective one, and, must be exteneively nsed by those householders who desire to protect their property from burglars.”’ APPLICATION OF THE Sann-Buast.—The most recent application of the eand-blast is for cleaning the fronts of huildinge by removing the soot, dust, and other substances therefrom. The impact of the sand on the eurface removes the soot or dust from all the crevicesand indentatione, without perceptibly interfering with the eharpness of the architeatural ornamenta£ a ER Soe. Arts, Sixotk-aam Rarpway.—In a late issno we described 2 novel plan, receatly put in operation in Georgia, by which locomotivo aud care would require only a eiugle rail. An English exchange thus comments ou it; As the railway develops, ite proportions contract. The wido gange of six and eeven feet bas dwindled hy tnrns to the narrow gaage of 4ft. 8in., to tho weter gange of 3914 in., to the Islo of Mau gauge of three fect, to the talked-abont 33 inch, and to the really executed two-feet Festiniog. The last-meutioued narrow gauges have becu completely ontdone by the ‘‘prismoid, or onetrack railway,'’ recently constructed at Atalanta, Georgia. This is built np of severel tbickuesses of plank and is saidto resemble tho "inverted keel of a vessel with a flat railon the apex.’ A railway track of this kiad can he bailt at tbe cost of three thousand dollars per mile. The engine is a four-ton locomotive, or stesm bicycle, which is fitted with flanges on tho ontside of each wheel, locking, itis said, the rolling stoek tothe prism. Vhisis probably very woll enited for a street railroad in Atalanta, or any other fastly-named place that is not ina horry. No doubt it wenld run, aftera fashion, hut the difference in the amonnt of friction incurred hy the varions parte of the broad flauge would alone disqualify the invention from any elaim to practical utility. Something prismoidal was, if we mistake not, tried on the Semniering some years ago, with the view of snrmounting the difficulties of a steen gradieat, but was abandoned on account of unequal friction. No high rate of speed can be ohtained by ‘‘fancy’’ machines made in defizace of wellknown laws, and, althongh it may be amusing to many to see the railway rednced to its lowest terms, the experiment will prove far more carious than neetnl. How Mirnors aaz Siiveavn.—The following description of ‘*’silvering '’ plate glass for mirrors is mainly founded upon the method pureued al St. Gobiu and Raveuhead. After polishing, each glase tablet intended to make a lookiag-glass is silvered, or, more oorrectly, coated on one side with an amalgam of tin. In the preparation of this amalgam tiatoil is nsed, but it mnst he beaten from the finest tin, and possess a sprface similar to that of polished silver. ‘The art of silvering is simple, and merely requires dexterity. The glass plate having been thoronghly cleansed from all gresse and dirt with putty-powder and wood ash, the workman proceeds to lay a sheet of tinfoil smoothly upou the table, carefully pressiag out with a cloth dabber all wrinkles and places likely to form air bubbles. He spreads over it a quantity of mercury, taking cere that all parts are equally covered. and then the glass plate is pushed gently on to the surface, commencing at one edge. The glass is allowed to remain for twenty-four honrs; it is then removed to a wooden incliue similar to a reading-desk, to allow of the excess of mercury draining off. As the amalgam gradually sets, the incline is increased till finally the plate reaches the perpendicular, when the process isifinished, and the mirror removed to -the store-room. over ten years working ont his ideas, and has . “Iyrpuoven’’ MzTHOD oF PropenirNo Beats, ---We notice the following description of a propelling apparatns in general circnlation. We recollect having seen already sevezal models of this most valuable idea, and do not nnderstand how it can be patentahle: To the bar or lever of the paddle are hingedtwo blades in sucha way that when moviag forward through the water the pressure of the water will close them. These are kept from closing against each other by one or more stops, interposed between them and attached to the bar, so that as the paddle begins to make the stroke the pressure of the water may open or spread the-bladea so as to present the greatest possible snrface. The upper ends of the bsr are designed to be attached to the shafts, which are arrauged so as to he operated independently of esch other. The shafts are placed in line with each other, and a;pintel may be attached to the end of one shaft to enter a socket inthe end of the other shaft. Levers are attached to the iuner parts of the shafts, extending above and below said shafts, and having handles attached to theirjnpper ends and foot.rests attached to their lower ends, so that the operator cen apply hand and foot power. Tue ARTILLERY OF THE PEaton.—The monster weapone with which the turrets of the ironclads of the futnre will he armed, will far surpass the most powerful artillery at present in existence, the Woolwich Infante of 35 tons weight, and a bore of 12 in. in diameter, and the greet guns which Krupp is now making for the Germans being alike eclipsed hy the new weapon, which will have a bore of nearly 15 in., aud weigh 60 tons. These guns will be built by coil upon coil of wrought-iron and a eteel tnbe; a aystem which inenres the greatest poasible atrength and immnnity from danger of hnrsting, and practicelly imposes no limit to the size of the guns. They will be fitted with a movable hreech-loading arraagement. The Woolwich Infant will throw a 700 pound ehot six or eeven miles: the new gun will hurl a projectile weighing 1,100 pounds, (half a ton), over a range which has yet to be determined. As the antitheeie of this enormons gnn, the new eteel mountain gun has now heen placed in the model room of the Royal Gun Factories. The gun weighs only 200 ponnds, hut it can fire a ehell of 7 pounds, with good effect, up to 3,000 yards, and with its little carriage is designed to he conveyed on the hacks of mulee, — Iron Monger.