Volume 31 (1875) (428 pages)

July 3, 1875.] MINING AND SCIENTIFIC PRESS. 6 ri ECHANICAL ProcRess Resistance of Woods to Torsional Sfrain. Professor R. H. Thurston, of ths Stevens Institute of Tecbnology, Hoboken, N.J., has heen making some experiments to ees how different woods will bear a twist, and gives the following as his resnits : ' The test pieces wera seven-eights ofan inch in thickness, at the middle nr amallest part, and were made from the following woods : White ine, S., yellow pino (sap wood), S. yellow pine eart wnod), black aprnce, ash, black walnut, red cedar, spanish mahogany, white oak, hiokory, locnst and chestnut. Tha conolnsions drawn are as follows : Whita pine yields quite rapidly as the torsional moment increases. The mazimnm strength of the test piecs was 15 1-2 foot pounds, and it was twisted completely off at a total anglo of torsion of 130 deg. The substance is thns shown to have little resilienca. Yellow pine has mnch greater strength, stiffoess and resilience. The sap wood is equally stiff with the heart wood, hut sooner passes its limit of elasticity. Spruce is less stiff than white pine, even, bnt possesses groater strength and resilience, its moment of resistance reaching 18 foot pounds, and twisting throngh a total angle of torsion of 200 deg. Ash scems to he weaker and less tongh than ia generally snpposed. Its mnst atriking peculiarity is its very rapid Inse of strength after passing its limit of elasticity. Black walont is very stiff, strong nud resilient, and is hnt little inferior to oak. Its resistiog moment reaches 35 foot ponnds and one speoimen attained a total angle of torsion of 220 deg. Red cedar is stiff hnt hrittle, and loses all power of resistance after twisting through an angle of 92 deg. A torsions] moment of 20 foot ponnds only produced a total angle of torsion of 50 deg. Spanish mahogany is very stiff and strong. It fs deficient in toughness and resilience, losing ite power of resistanca very rapidly after passing the limit of clasticity. White oak has less toreional etreugth than either good mahogany, loenst or hickory, but is remarkable for its wonderful toughuess. It passes its limit of elasticity at 15 deg., but loseaits resieting power very slowly. Tha latter remains unimpaired to a torsion of 70 deg., aud yields completely at 253 deg. Millwrights are evidently correct in holding this wood in high esteem for strength, toughness, and power of resisting heavy shocks and strains. Hickory has apparently the highest ultimate torsional streugth combined with nnnsnal etiffuess and considerable resilience. Its moment of resistance to torsion reaches a maximnm of 58 foot pounds. Looust has greater stiffpess than nny other wood ou the list, and stands nextto hiokory in strength; it is also very resilient. A New Use ror Oast Inon.—Measrs. West & Patterson have recently introdnced iu Pittsburg a new and neat orticla under the name of Tank's Grave Guards. Though n grave subjectit is nevertheless an indispensable oue. ‘fhese gusrds are designed for the purpose of preserving the symmetry of burial mounds. They are made of metal, cast in moulds of various patterns, with a sqnare socket on each end for holding the head and foot etones securely in position. The casting is open in the middie, allowing the mound to project through so that flowers may be planted and kept in their proper place hy the sides of the gnard. The whole casling is painted white, or ornamented, and may be made to represent mottled or white marble. They are durable from the fact that cold weather will not break them, nor will they rust when well paintéd, and are very much cheaper than marble or stone, being sold at about one-third the cost of marble. They may be seen at No. 132 Smithfield street. Stexu yor Beits.—The greatly rednced price of steel is gradnally introdncing that metal into very general nse. It has of late been largely used for belle. One of its advantages for such purposes has been alluded to in a late German paper as follows: The three cast-steel bells which fell at the bnrning of the church of the German Reformed community at St. Petersburg have again been hnng, and are} found to be none the worse for several honrs’ endurauoce of a furnace-likeheat, One of these bells, which was cast at the Bochunervercins factory, hns historic antecedents. It was presented to the St. Patersburg community after the invasion of Denmark by tha King of Prussia; and now that it has been again hung, itis proposed to change its name from King William, which it formerly bore, to the Emperor William: Bano Saws vs. Crrocnan Saws.—The German industrial papers are discussing the question of the disadvantsges of circular sawe as compared with band saws: 1st. Oircnlar eaws are very dangeronetothe workmen. 2d. They require a much Sreater power to drive them than any other kind. 3d. They make a much wider cut, producing more waste, and thus fewer products froma given amount of material. The only advantage is that the cost of ro a circular saw is less than that of a and saw; but notwithstanding, the Mechanics’ Association (Gewerbverein) of Muehlhausen have already published in their yearly report the advice to abolish their uee wherever it is practically poesible to do so; and. this. is of conrse the case in the great majority of cir. cumstances, The Bessemer Channel Steamer, The muoh talked of experiment of Mr. Besgemoer—a swinging saloon for avoiding sea aickness in crossing the English ohanuel—seoms tn have proven a failnre. Atall events Mr. Bessemer has fonnd it necessary to abandon ths idea of making the cabin maintain its level antomatically, ond now entrusts that duty to a man who stands in tha center of the cabin watching n spirit level, and managing with a sioglo lever a complicated and powerful system of hydranlio brakes. Any one who knows hy experience how difficnlt it ie to hold a spirit lever perfectly motionless, will nuderstind the delicacy nf the task which this Bessewer hrakeman has to accomplish. The incessant motion of the restless waves has to he oonnteracted by an eqnally incessant movemeut of the lever, A moment's inattention or carelessness, and the swinging cahin swings madly through an nre of many degrees. We do not nnderstaud, however, thet he has entirely given np his projeot; that he is still hopeful of making it a suecess is qnite probahle and natursl. ut there can be no doubt but that heis sorely disappointed at the result thua far. Perhaps it may he truthfully said that the swinging saloon has not yet been tested nuder conditions favorahle to the formstion of an intelligent and nnprejadiced opiuion of the prncticahility of the idea, and the fact that it was allowed to remain fixed during the public trial trip, nlthough all the machinery for msintaining its equihbrinm was in position, msy he reparded as indioating that Mr, Bessemer and Mr. Reed, his architect and contractor, have no preat faith in its successful working. The English papers express doubts thatit will ever be regniarly employed in the channel servioe, owing to its unmanageableness in entering and leavingthe Calais harbor. This, however, remains to be dotermined, We certainly hope that Mr, Bessemer will succeed in making bis ship a success, and that to the disappointment which he doubtless alrendy feels will not be added the mortification of complete and final failure. 8 The Engineer expresses an opinion that th swinging saloon, even if it ia made to work, will never prevent sea sickness; yet it is always hest to avoid an over confident opinion with regard to an experiment which does not absolutely imply in itssuccess a positive nullificatiou of well known natural laws. The declsratiou of Lardner that it was folly to think of crossing the Atlantic with a steamboat; the jeering of Davy atthe idea of lighting the streets of London with gas, and the incredibility of other savants with regard to the assumed possibilities of railroad traveling in the early days of the locomotive, will always stand out a8 sO Many warnings against the propriety of condemning the future of anything which admits of a scientific possibility. Perpetua Motion Unmsr GovganmMent PatronaGce.—It appears from a statement in the Manufacturer and Builder that the notorious H. M. Paine, well known throughout the coun'ry for his mauy attempts to utilize foolieh and impracticable schemes, is now at work in New York nnder Government patronage, in the construction of a af perpetual motion machine!*’ He proposes the absnrdity that a colnmn of water, say 300 feet high, and hence with a pressure of 150 pounds per square inch, is capable, by the employment of certain mechanism, of moving an engine without any expenditure of water whatever—by simple pressnre alone! Hence, every man with a water pipe in his house, of ordinary pressure, may apply that pressure to an extent proportioned to the pressure and size of pipe, to any desired mechanical purposes. If so, why will not a pile of brick, or stone, or sand, answer the same purpose—why insist upon water alone? We leave our readera to ponder over such an absurdity, and place their estimate npon the engineering capacity of the Government offieer who conld lend himself to snch a swindle. The statement seems almost incredible; yet we find it, In detail, ocenpying nearly a page in the journal mentioned, with the principle of the meohanism fully illustrated and described. We sbould add, however, that the Manufacturer ridicules the idea a9 absurd in the extreme. BessEMEa STEEL IN SweneN.—According to late accounts there are now thirteen Bessemer steel works in operation in Sweden. In most of the works great attention is being paid to the production of extremely soft steel, for the manufacture of armor plates for ships. The greatest difficulty encountered in tbe works is in keeping up a uniform character of steel, for the reason that, for the sake of economy in production, the Bessemer steel converters are fed direct from the blast furnace. A good and uniform steel has not yet been prodnced direct from the ore; although itis most important step in the progress of iron manufacture to turn ont even a very inferiorsteel by that cbean and rapid process. The possibilities of the future in this direction are hizhly encouraging. Steen Direor raom tHe Orz.—Ata recent meeting of the Iron aud Steel Institute, of England, one of the epeakere, with tbe obyione endorsement of the other membere preseut, amoug whom were some of the most eminent metallurgists, spoke confidently of the prospect there appeared of steel being mannfactured as easily and cheaply from the ore as iron i3 now. An interesting fact in this connection will be fonnd in this department, under the head of “ Bessemer Steel in Sweden.” ScienTiFic ®Proaress. The New Discoveries in Regard to Light. —The Impact (?) of a Luminous Ray. We allnded soma weeks siuce to an interesting discovery by Mr. Crookes, iu relation to what appears to bea hitherto nnknown property of light, by which it possesses direct meohanical powcr, as if by impact, in rotating a wheel constructed similarly to n steamboat, but hung horizontally, its axis rostiug upon a pivot. This discovery is considered the most import. aut since the day whon the possibility of spectrnm nnalysis was first made known. The first discoveries by Mr. Crookes were made known to the Roval Society in Augnst, 1873; hut his more receut discoveries, whioh are still more remarkable, were first described there in April last. Mr. John Evans, F. 8. S., President of the Geological Society, ocoupied the chair, and amoung tha listeners present were the two Seoretarios, Professor G. G. Stokes, aud Professor Huxley; nlso, Dr. Wm. Huggins, Mr. O. W. Siemens, Mr. J. Norman Lockyer, Dr. W. B. Carpenter, Professor Maskelyne, and Dr. J. H. Gladstone. Mr. Crookes began by ststing that, in the psper which he had previously read to the society, he had made kuown how a lever arm of pith, delicately ae ina very perfect vacuum, was repelled by the impaot of light or radiaot heat. A great condilion of success in the experiments was to work with the highest possible rarefication; consequently the lever aris were suspended in glass bulbs from which the sir had been exhsnsted by means of the Sprengel pump, which gives a far more perfect yacuum tbnn can be obtained by the nse of any other apparatus. j Until these experiments were made it was supposed that light had no action upon a lever arm of small ponderosity snspended in vaouo. Indeed, the circumstance that light could not turn a lever arm so snspended has been quoted in stendard scientific text-books, hy Dr. Balfour Stewart and others, as one point in the long chaiu of evidence azainet Newton’s emission theory of light. But Mr. Crookes last week exhibited a har of pith euspended by a cocoon fiber in a large glass bulb very well exhausted. When a lighted candle was placed about two inohes from this bulb the pith bar began to swing two andfro, the swing gradually iucreasing in amplitude until the dead center was passed over, wheu several complete revolntions were made. The torsion of the suspended fiber then offered resistance to the revolutions, after which tbe bar began to turn in the opposite direction, nnd so on alternately. These movements were kept np with energy and regularity so long as the candle continued to born. When instead of a candle a piece of ice was placed near the bulb, one end of the lever arm came towards it as if attracted; but the truth was, as explaiued by Mr. Crookes, that radiant heat was acting upon the pith bar from all parts of the room, and that the presentation of the piece of ice lowered the radiation on one eide; consequently the movement was really cansed by repulsiou acting in the opposita direction. Tha amount of repulsion produced could be measured. The advantage which a glass thread possesses over a cocoon fiber is that the index always goes back to zsro. The fibres used to snspend the arms are 80 excessively fine that when the end of ous of themis heldin the hand the fiber usually curls upward like a cobweb until the other end of it floats almost vertically in the air. As the vacunm becomes less perfect the repnision grows less, until at last the neutral point is réached whera there is no actiou at all. If still more airbe then admitted, attraction instead of repnision sets in. The barometric pressnre of the neutral poiut varies with the density of the suspended substance on which the rndiation falls; it varies also with the ratio of its mass to its surface, and with several other conditions. Thns the neutral point for a thin sutfacs of pith beiug low, whilst that fora moderately thick piece of platinum is high, it follows that, with a rarefication intermediate between these two points, pith will be repelled while platinum willbe attracted by the saute . power of radiation. Mr. Crookes proved this experimentally, by showing simnitsneous attraction and repulsfon by the same ray of light. When these expariments were first made kuown, some of the observers tried to account for the effects by the assumed action of feeble air ourreuts or of electricity, but both these hypotheses were considered by Mr. Crookes to be abundsntly disproved. Professor Osborne Reynolds suggested that the movement might be due to evaporation and condensation at the eurface of the enspended body. Mr. Crookes had a thick and etrong bulh blown at the end of a piece of difficnltly fusible green graes, epecially made for boiler gangee. In it he enpported a thin bar of aluminum at the end of a long platinum wire, the upper end of which wire wae piesed through the top of the tube and well sealed for electrical purposes. The apparatus was sealed by fusion to the Sprengel pump, aud the exhanstion was kept going on for two days, until an induction spark refnsed to pase acroes the vacuum. During this time the bulb and its contents were several times raised to a dull red heat. At the end of the two days’ exhanstion the alnminum bar wae found to behave in the eame manner as, bnt in astrouger degree, than it would in a less perfectly exhansted apparatus, namely, it was repelled by heat of low intensity and attracted by cold, Meteoric Dust. Tissandier has conceived the Inminous idea of looking for the meteoric dnet in snow water; during a rain storm it is lost iu the soil, hntif snow be collected, the dust in suspension may he fonnd after melting the snow. He publishes the following facts: If twenty-two gsllons of snow water be evaporated to dryness, there remains a residue varying from 0.048 grammes, in tue country equal to 0.212 grammes in Paris; this residua consists of a fine gray powder, the organic matter of which, being rich in carbon, burns brightly, and leaves nearly 60 per cent. of ashes, oomposed of silica, carbonate of lime, alnmina, chlorids, sulphates and a larga amount ofiron. Asa crucial test he melted a large body of snow fonnd at a high altitude in Finland, remote from human habitation, and fonnd minute particles of magnetic iron. As metzorites often contain magnetic iron, this is a verification of the theory that our earth is continually receiving accessions, if not of large meteorites, at least of meteoric dust. Groveman brings this factin connection with the aurora borealis, and proposes the hypothesis that the myriads of floating particles of msgnetized iron, in entering our atmosphere, hecome incandescent, and arranging themselves nnder the influence of the terrestrial maguetiom, groupin magnetic lines iu the same way as steel filings do under the infinenoe of amagnet. Tbe theory, however ingenious, does not sufficiently account for the disturhauce of the compass needle during the anrora, nor for the duration of this phenomena for hours, as the hurning of small particles of iron can give only instantaueous flushes. We would ask the hypothesis that the floating iron psrticles make the region above onr atmosphere a better conductor than the highly rarefied vacuam prevailing thero (the absolnte vacuum being found to be an absolute nonconductor); the electrio currents from the charged upper regions over the poles, towards the damp conducting atmospheres over tha equator, conducted by the metallic meteorio dust inthe upper regions above onr atmos~ phere, or vice versa, canse the lumiuous rays which we call the anrora borealis. Action or Exeorgicirs on Isox.—fhe remarkable phenomena first observed by Prof. Gore, which consists in a very perceptible twisting of a har of iron by the joint effeots of currents of electricity passing longitudinally through, and also around such a bar by meaus of the insulated wire of an enveloping helix, has been fnrther investigated. Subseqnent experiments have shown that such twisting may ba made to reach full one-quarter of a revolntion. It has also been ascertained that both cnrrents are necessary to the development of the phenomens. Either current, when applied separately, simp!y produces the ordinary effect of magnetizing the bar. The direction of the twist is definitely related tothe direction of the cnrrent in the helix. In order to produce the fullest effect, the currents must bs simultaneous. When they are successive a perceptible twist resnlts in a lesser degree, Far Deoomposen BY Sanur Watea.—M. Marticonana, a manufacturer in San Sebastian, long ago remarked that the fat which remained attached to salted skins was decomposed. Recently hnving hought fat which for a long time had been in contact with sea water, he had it washed with acidulated water, then with pure water, and finally pressed, when he obtained the fatty acide: steario, margaric and oleic. This conforms to what at present is known concerning fats; rancidity of fats is nothing bnt ‘decomposition, the glycerine separating from the fatty acids, and the fats from being neutral when fresh, become acid when old and rancid. It appears that the contact of salt water hastens this decomposition, while heat does this still more. Fat inclosed with water in a veesel and submitted to a heat of some 300° to 400° Fah. (of conrse under pressnre), will, when kept in oontinuons circulation, he decomposed in eight hours. Spectrum oF Cooara’s Comet.—Spectroscopic observations on Coggia’s comet, made at Greeuwich obseryntory, show the spectrom of carbonic acid gas. When this gas was illuminated by the electric spark from an induction coil without a Leyden jar attached, the spectrum was nearly identical with that of the comet. Two bright bauds were always coincident, but occasionally the ooma of the comet gave 4 faint continuons spectrum in addition, while the spectrum of the nncleus wae always oontinuous, and contained numerous bright bande, and three or four dark lines in the yellow and green, Metvoronooy.—Experiments were made in Frauce last year to test how far the humidity of the atmosphere is affected hy forests. One eet of instruments for recording humidity was placed in the forest, and the other in the open air, a ahort distance off. The records showed that more rain fell each month in the foreet than in the open air, and the total rainfall for six months was seven and one-half inohes in the forest, and in the open field less thanseyen Vinches.

July 3, 1875.] MINING AND SCIENTIFIC PRESS. 6 ri ECHANICAL ProcRess Resistance of Woods to Torsional Sfrain. Professor R. H. Thurston, of ths Stevens Institute of Tecbnology, Hoboken, N.J., has heen making some experiments to ees how different woods will bear a twist, and gives the following as his resnits : ' The test pieces wera seven-eights ofan inch in thickness, at the middle nr amallest part, and were made from the following woods : White ine, S., yellow pino (sap wood), S. yellow pine eart wnod), black aprnce, ash, black walnut, red cedar, spanish mahogany, white oak, hiokory, locnst and chestnut. Tha conolnsions drawn are as follows : Whita pine yields quite rapidly as the torsional moment increases. The mazimnm strength of the test piecs was 15 1-2 foot pounds, and it was twisted completely off at a total anglo of torsion of 130 deg. The substance is thns shown to have little resilienca. Yellow pine has mnch greater strength, stiffoess and resilience. The sap wood is equally stiff with the heart wood, hut sooner passes its limit of elasticity. Spruce is less stiff than white pine, even, bnt possesses groater strength and resilience, its moment of resistance reaching 18 foot pounds, and twisting throngh a total angle of torsion of 200 deg. Ash scems to he weaker and less tongh than ia generally snpposed. Its mnst atriking peculiarity is its very rapid Inse of strength after passing its limit of elasticity. Black walont is very stiff, strong nud resilient, and is hnt little inferior to oak. Its resistiog moment reaches 35 foot ponnds and one speoimen attained a total angle of torsion of 220 deg. Red cedar is stiff hnt hrittle, and loses all power of resistance after twisting through an angle of 92 deg. A torsions] moment of 20 foot ponnds only produced a total angle of torsion of 50 deg. Spanish mahogany is very stiff and strong. It fs deficient in toughness and resilience, losing ite power of resistanca very rapidly after passing the limit of clasticity. White oak has less toreional etreugth than either good mahogany, loenst or hickory, but is remarkable for its wonderful toughuess. It passes its limit of elasticity at 15 deg., but loseaits resieting power very slowly. Tha latter remains unimpaired to a torsion of 70 deg., aud yields completely at 253 deg. Millwrights are evidently correct in holding this wood in high esteem for strength, toughness, and power of resisting heavy shocks and strains. Hickory has apparently the highest ultimate torsional streugth combined with nnnsnal etiffuess and considerable resilience. Its moment of resistance to torsion reaches a maximnm of 58 foot pounds. Looust has greater stiffpess than nny other wood ou the list, and stands nextto hiokory in strength; it is also very resilient. A New Use ror Oast Inon.—Measrs. West & Patterson have recently introdnced iu Pittsburg a new and neat orticla under the name of Tank's Grave Guards. Though n grave subjectit is nevertheless an indispensable oue. ‘fhese gusrds are designed for the purpose of preserving the symmetry of burial mounds. They are made of metal, cast in moulds of various patterns, with a sqnare socket on each end for holding the head and foot etones securely in position. The casting is open in the middie, allowing the mound to project through so that flowers may be planted and kept in their proper place hy the sides of the gnard. The whole casling is painted white, or ornamented, and may be made to represent mottled or white marble. They are durable from the fact that cold weather will not break them, nor will they rust when well paintéd, and are very much cheaper than marble or stone, being sold at about one-third the cost of marble. They may be seen at No. 132 Smithfield street. Stexu yor Beits.—The greatly rednced price of steel is gradnally introdncing that metal into very general nse. It has of late been largely used for belle. One of its advantages for such purposes has been alluded to in a late German paper as follows: The three cast-steel bells which fell at the bnrning of the church of the German Reformed community at St. Petersburg have again been hnng, and are} found to be none the worse for several honrs’ endurauoce of a furnace-likeheat, One of these bells, which was cast at the Bochunervercins factory, hns historic antecedents. It was presented to the St. Patersburg community after the invasion of Denmark by tha King of Prussia; and now that it has been again hung, itis proposed to change its name from King William, which it formerly bore, to the Emperor William: Bano Saws vs. Crrocnan Saws.—The German industrial papers are discussing the question of the disadvantsges of circular sawe as compared with band saws: 1st. Oircnlar eaws are very dangeronetothe workmen. 2d. They require a much Sreater power to drive them than any other kind. 3d. They make a much wider cut, producing more waste, and thus fewer products froma given amount of material. The only advantage is that the cost of ro a circular saw is less than that of a and saw; but notwithstanding, the Mechanics’ Association (Gewerbverein) of Muehlhausen have already published in their yearly report the advice to abolish their uee wherever it is practically poesible to do so; and. this. is of conrse the case in the great majority of cir. cumstances, The Bessemer Channel Steamer, The muoh talked of experiment of Mr. Besgemoer—a swinging saloon for avoiding sea aickness in crossing the English ohanuel—seoms tn have proven a failnre. Atall events Mr. Bessemer has fonnd it necessary to abandon ths idea of making the cabin maintain its level antomatically, ond now entrusts that duty to a man who stands in tha center of the cabin watching n spirit level, and managing with a sioglo lever a complicated and powerful system of hydranlio brakes. Any one who knows hy experience how difficnlt it ie to hold a spirit lever perfectly motionless, will nuderstind the delicacy nf the task which this Bessewer hrakeman has to accomplish. The incessant motion of the restless waves has to he oonnteracted by an eqnally incessant movemeut of the lever, A moment's inattention or carelessness, and the swinging cahin swings madly through an nre of many degrees. We do not nnderstaud, however, thet he has entirely given np his projeot; that he is still hopeful of making it a suecess is qnite probahle and natursl. ut there can be no doubt but that heis sorely disappointed at the result thua far. Perhaps it may he truthfully said that the swinging saloon has not yet been tested nuder conditions favorahle to the formstion of an intelligent and nnprejadiced opiuion of the prncticahility of the idea, and the fact that it was allowed to remain fixed during the public trial trip, nlthough all the machinery for msintaining its equihbrinm was in position, msy he reparded as indioating that Mr, Bessemer and Mr. Reed, his architect and contractor, have no preat faith in its successful working. The English papers express doubts thatit will ever be regniarly employed in the channel servioe, owing to its unmanageableness in entering and leavingthe Calais harbor. This, however, remains to be dotermined, We certainly hope that Mr, Bessemer will succeed in making bis ship a success, and that to the disappointment which he doubtless alrendy feels will not be added the mortification of complete and final failure. 8 The Engineer expresses an opinion that th swinging saloon, even if it ia made to work, will never prevent sea sickness; yet it is always hest to avoid an over confident opinion with regard to an experiment which does not absolutely imply in itssuccess a positive nullificatiou of well known natural laws. The declsratiou of Lardner that it was folly to think of crossing the Atlantic with a steamboat; the jeering of Davy atthe idea of lighting the streets of London with gas, and the incredibility of other savants with regard to the assumed possibilities of railroad traveling in the early days of the locomotive, will always stand out a8 sO Many warnings against the propriety of condemning the future of anything which admits of a scientific possibility. Perpetua Motion Unmsr GovganmMent PatronaGce.—It appears from a statement in the Manufacturer and Builder that the notorious H. M. Paine, well known throughout the coun'ry for his mauy attempts to utilize foolieh and impracticable schemes, is now at work in New York nnder Government patronage, in the construction of a af perpetual motion machine!*’ He proposes the absnrdity that a colnmn of water, say 300 feet high, and hence with a pressure of 150 pounds per square inch, is capable, by the employment of certain mechanism, of moving an engine without any expenditure of water whatever—by simple pressnre alone! Hence, every man with a water pipe in his house, of ordinary pressure, may apply that pressure to an extent proportioned to the pressure and size of pipe, to any desired mechanical purposes. If so, why will not a pile of brick, or stone, or sand, answer the same purpose—why insist upon water alone? We leave our readera to ponder over such an absurdity, and place their estimate npon the engineering capacity of the Government offieer who conld lend himself to snch a swindle. The statement seems almost incredible; yet we find it, In detail, ocenpying nearly a page in the journal mentioned, with the principle of the meohanism fully illustrated and described. We sbould add, however, that the Manufacturer ridicules the idea a9 absurd in the extreme. BessEMEa STEEL IN SweneN.—According to late accounts there are now thirteen Bessemer steel works in operation in Sweden. In most of the works great attention is being paid to the production of extremely soft steel, for the manufacture of armor plates for ships. The greatest difficulty encountered in tbe works is in keeping up a uniform character of steel, for the reason that, for the sake of economy in production, the Bessemer steel converters are fed direct from the blast furnace. A good and uniform steel has not yet been prodnced direct from the ore; although itis most important step in the progress of iron manufacture to turn ont even a very inferiorsteel by that cbean and rapid process. The possibilities of the future in this direction are hizhly encouraging. Steen Direor raom tHe Orz.—Ata recent meeting of the Iron aud Steel Institute, of England, one of the epeakere, with tbe obyione endorsement of the other membere preseut, amoug whom were some of the most eminent metallurgists, spoke confidently of the prospect there appeared of steel being mannfactured as easily and cheaply from the ore as iron i3 now. An interesting fact in this connection will be fonnd in this department, under the head of “ Bessemer Steel in Sweden.” ScienTiFic ®Proaress. The New Discoveries in Regard to Light. —The Impact (?) of a Luminous Ray. We allnded soma weeks siuce to an interesting discovery by Mr. Crookes, iu relation to what appears to bea hitherto nnknown property of light, by which it possesses direct meohanical powcr, as if by impact, in rotating a wheel constructed similarly to n steamboat, but hung horizontally, its axis rostiug upon a pivot.

This discovery is considered the most import. aut since the day whon the possibility of spectrnm nnalysis was first made known. The first discoveries by Mr. Crookes were made known to the Roval Society in Augnst, 1873; hut his more receut discoveries, whioh are still more remarkable, were first described there in April last. Mr. John Evans, F. 8. S., President of the Geological Society, ocoupied the chair, and amoung tha listeners present were the two Seoretarios, Professor G. G. Stokes, aud Professor Huxley; nlso, Dr. Wm. Huggins, Mr. O. W. Siemens, Mr. J. Norman Lockyer, Dr. W. B. Carpenter, Professor Maskelyne, and Dr. J. H. Gladstone. Mr. Crookes began by ststing that, in the psper which he had previously read to the society, he had made kuown how a lever arm of pith, delicately ae ina very perfect vacuum, was repelled by the impaot of light or radiaot heat. A great condilion of success in the experiments was to work with the highest possible rarefication; consequently the lever aris were suspended in glass bulbs from which the sir had been exhsnsted by means of the Sprengel pump, which gives a far more perfect yacuum tbnn can be obtained by the nse of any other apparatus. j Until these experiments were made it was supposed that light had no action upon a lever arm of small ponderosity snspended in vaouo. Indeed, the circumstance that light could not turn a lever arm so snspended has been quoted in stendard scientific text-books, hy Dr. Balfour Stewart and others, as one point in the long chaiu of evidence azainet Newton’s emission theory of light. But Mr. Crookes last week exhibited a har of pith euspended by a cocoon fiber in a large glass bulb very well exhausted. When a lighted candle was placed about two inohes from this bulb the pith bar began to swing two andfro, the swing gradually iucreasing in amplitude until the dead center was passed over, wheu several complete revolntions were made. The torsion of the suspended fiber then offered resistance to the revolutions, after which tbe bar began to turn in the opposite direction, nnd so on alternately. These movements were kept np with energy and regularity so long as the candle continued to born. When instead of a candle a piece of ice was placed near the bulb, one end of the lever arm came towards it as if attracted; but the truth was, as explaiued by Mr. Crookes, that radiant heat was acting upon the pith bar from all parts of the room, and that the presentation of the piece of ice lowered the radiation on one eide; consequently the movement was really cansed by repulsiou acting in the opposita direction. Tha amount of repulsion produced could be measured. The advantage which a glass thread possesses over a cocoon fiber is that the index always goes back to zsro. The fibres used to snspend the arms are 80 excessively fine that when the end of ous of themis heldin the hand the fiber usually curls upward like a cobweb until the other end of it floats almost vertically in the air. As the vacunm becomes less perfect the repnision grows less, until at last the neutral point is réached whera there is no actiou at all. If still more airbe then admitted, attraction instead of repnision sets in. The barometric pressnre of the neutral poiut varies with the density of the suspended substance on which the rndiation falls; it varies also with the ratio of its mass to its surface, and with several other conditions. Thns the neutral point for a thin sutfacs of pith beiug low, whilst that fora moderately thick piece of platinum is high, it follows that, with a rarefication intermediate between these two points, pith will be repelled while platinum willbe attracted by the saute . power of radiation. Mr. Crookes proved this experimentally, by showing simnitsneous attraction and repulsfon by the same ray of light. When these expariments were first made kuown, some of the observers tried to account for the effects by the assumed action of feeble air ourreuts or of electricity, but both these hypotheses were considered by Mr. Crookes to be abundsntly disproved. Professor Osborne Reynolds suggested that the movement might be due to evaporation and condensation at the eurface of the enspended body. Mr. Crookes had a thick and etrong bulh blown at the end of a piece of difficnltly fusible green graes, epecially made for boiler gangee. In it he enpported a thin bar of aluminum at the end of a long platinum wire, the upper end of which wire wae piesed through the top of the tube and well sealed for electrical purposes. The apparatus was sealed by fusion to the Sprengel pump, aud the exhanstion was kept going on for two days, until an induction spark refnsed to pase acroes the vacuum. During this time the bulb and its contents were several times raised to a dull red heat. At the end of the two days’ exhanstion the alnminum bar wae found to behave in the eame manner as, bnt in astrouger degree, than it would in a less perfectly exhansted apparatus, namely, it was repelled by heat of low intensity and attracted by cold, Meteoric Dust. Tissandier has conceived the Inminous idea of looking for the meteoric dnet in snow water; during a rain storm it is lost iu the soil, hntif snow be collected, the dust in suspension may he fonnd after melting the snow. He publishes the following facts: If twenty-two gsllons of snow water be evaporated to dryness, there remains a residue varying from 0.048 grammes, in tue country equal to 0.212 grammes in Paris; this residua consists of a fine gray powder, the organic matter of which, being rich in carbon, burns brightly, and leaves nearly 60 per cent. of ashes, oomposed of silica, carbonate of lime, alnmina, chlorids, sulphates and a larga amount ofiron. Asa crucial test he melted a large body of snow fonnd at a high altitude in Finland, remote from human habitation, and fonnd minute particles of magnetic iron. As metzorites often contain magnetic iron, this is a verification of the theory that our earth is continually receiving accessions, if not of large meteorites, at least of meteoric dust. Groveman brings this factin connection with the aurora borealis, and proposes the hypothesis that the myriads of floating particles of msgnetized iron, in entering our atmosphere, hecome incandescent, and arranging themselves nnder the influence of the terrestrial maguetiom, groupin magnetic lines iu the same way as steel filings do under the infinenoe of amagnet. Tbe theory, however ingenious, does not sufficiently account for the disturhauce of the compass needle during the anrora, nor for the duration of this phenomena for hours, as the hurning of small particles of iron can give only instantaueous flushes. We would ask the hypothesis that the floating iron psrticles make the region above onr atmosphere a better conductor than the highly rarefied vacuam prevailing thero (the absolnte vacuum being found to be an absolute nonconductor); the electrio currents from the charged upper regions over the poles, towards the damp conducting atmospheres over tha equator, conducted by the metallic meteorio dust inthe upper regions above onr atmos~ phere, or vice versa, canse the lumiuous rays which we call the anrora borealis. Action or Exeorgicirs on Isox.—fhe remarkable phenomena first observed by Prof. Gore, which consists in a very perceptible twisting of a har of iron by the joint effeots of currents of electricity passing longitudinally through, and also around such a bar by meaus of the insulated wire of an enveloping helix, has been fnrther investigated. Subseqnent experiments have shown that such twisting may ba made to reach full one-quarter of a revolntion. It has also been ascertained that both cnrrents are necessary to the development of the phenomens. Either current, when applied separately, simp!y produces the ordinary effect of magnetizing the bar. The direction of the twist is definitely related tothe direction of the cnrrent in the helix. In order to produce the fullest effect, the currents must bs simultaneous. When they are successive a perceptible twist resnlts in a lesser degree, Far Deoomposen BY Sanur Watea.—M. Marticonana, a manufacturer in San Sebastian, long ago remarked that the fat which remained attached to salted skins was decomposed. Recently hnving hought fat which for a long time had been in contact with sea water, he had it washed with acidulated water, then with pure water, and finally pressed, when he obtained the fatty acide: steario, margaric and oleic. This conforms to what at present is known concerning fats; rancidity of fats is nothing bnt ‘decomposition, the glycerine separating from the fatty acids, and the fats from being neutral when fresh, become acid when old and rancid. It appears that the contact of salt water hastens this decomposition, while heat does this still more. Fat inclosed with water in a veesel and submitted to a heat of some 300° to 400° Fah. (of conrse under pressnre), will, when kept in oontinuons circulation, he decomposed in eight hours. Spectrum oF Cooara’s Comet.—Spectroscopic observations on Coggia’s comet, made at Greeuwich obseryntory, show the spectrom of carbonic acid gas. When this gas was illuminated by the electric spark from an induction coil without a Leyden jar attached, the spectrum was nearly identical with that of the comet. Two bright bauds were always coincident, but occasionally the ooma of the comet gave 4 faint continuons spectrum in addition, while the spectrum of the nncleus wae always oontinuous, and contained numerous bright bande, and three or four dark lines in the yellow and green, Metvoronooy.—Experiments were made in Frauce last year to test how far the humidity of the atmosphere is affected hy forests. One eet of instruments for recording humidity was placed in the forest, and the other in the open air, a ahort distance off. The records showed that more rain fell each month in the foreet than in the open air, and the total rainfall for six months was seven and one-half inohes in the forest, and in the open field less thanseyen Vinches.