Volume 38 (1879) (440 pages)

January 4 1879.] MINING AND SCIENTIFIC PRESS. TAY. dove, 8 ed Mechanica ‘PROGRESS. Tron in Car Construction. Mueh thonght and labor has beon expended iu ths construction of railroad ears, to obviate the necessity of earrying such alargs proportion of dead weight, as has hitherto been oonsidered necessary, whether for passengers or freight ; any improvement whieh will bring ahout a favorable change in the ratio between dead load and carrying capacity must bo of proportionate value, Mr. Albert F. Hill, of Cincinnati, recently read a very interesting paper on this subject, at a meoting of the Master Car Builders’ Association, from which we cxtract as follows : Remembering that the same mechanical priuciples which govern the design aud eon. struction of a bridge hold equally good in the eonstructiou of a roof or a warcbouse floor, etc., there can bo no impropriety in cousidering a freight car-body as a perambulating bridge, or a hridge on wheels. Conceding this viow of the subject to be tenable, it will not be difficult to determinn the proper principles which should govern and the proper materials which shonld enter into the construction of freight cars. Tho tendeucy to substitute iron for wood in enginecring and architectural structuros has of late years steadily increased, until at the present tine tho wooden railroad bridge has become the exception and theiron bridgo the rule, and it will not be long before steel will supersede the iron in large spans. In our cities, iron bnild. ings or stoue buildings with iron doors supersede every year more and more brick and wood. Durability, strength, lightness and elegance of construction, as well as true economy, are the principal qualities hy which metallic structnres . P’ commend themselves. Applyiug this to car construction, I think the point of greater, in fact considerably grester, durahility will bo readily conceded, Unfortunately, no reliable or rather positive informatiou as to the life of freight cars seems obtainable, under our present system of freight service, and the continual interchange of cars over the different lines, Still, barring accidents of course, it will be safe to assume the life of a car-body to vary from eight to ten years at the most. There are some few instances of greater durahility on record, but mostly on roads which have hnt little freight traffic and less interchange over other roads. The life of a metallic car, on the other hand, may safely be estimated at from 35 to 40 years. In order to illustrate his views, Mr. Hill instituted a minute comparison between the best constrneted ordinary wooden-box freight cars, and the iron car which he proposed. He dissect_ ed the wooden car piece by piece, giviug the weight and strength of each, and then rebuilt the same car with iron wherever that metal could be introduced. We have not tbe space to gointo the particnlars of this illustration, and can only give his conclusions, which were summed up as follows: I have made a rongh calculation of the weights in that car, and I get the following results (some of these are accurately calculated and others only approximately, hut near enough for all practical purposes): I get two trusses weighing 1,680 lbs.; rolled and wrought iron, 1,760 lbs.; cast iron, 300 1bs.; wood, nearly 4,000 Ibs, Ithink I might be ahle to do it with considerably less wood yet, but I have assumed the same floor system that is in this car, and that, with the end oak timbers and buffer blocks, and some inside lining, runs up to 4,000 lhs.; and of sheet iron, 2,260 lbs., making a total of 10,000 lbs. Now this car stands thus: Approximate weight of body, 10,000 lbs.—and the weight of the car will fall withiu that; itcan be constructed with less; then for two trucks, 8,700 lbs., making a total of 18,700 lbs. for the whole car ready for use, with a carrying capacity of 20 tons. The wooden car which has served in its general dimensions and general arrangements asa model for this metallic car has a carrying capacity of 12 tons, aud a total weight of 22,000 Ibs. Granting that this wooden car when new and in good condition, can carry 15 tons, though I think that this isthe maximum that ought to be putiu that car, we have increased the carrying capacity 25% and reduced the dead weight nearly the same amount. That a metallic car constructed as this is, will effect such savings as indicated liere, is open to the ealeulation of every oue of you. There is no difficulty in calenlating these strains and iu getting the amounts of metal that are necessary for those strains. The above-mentioned of gain in weight and capacity, it will be observed, is calculated for a car of the ordinary size of wooden cars; but Mr. Hill proposes to add greatly to the length of the cars when made of iron—or what would he still hetter, of steel. His ideal metal car would he at least 45 feet long, built upon the principle of} the truss bridge. _ bridge on wheels.” ‘Where the real saving in metallic cars will Indeed he calls his car ‘‘a come in will be by Isngthening them out, and lengthening thsm out considenaly. With every foot that you add, yon will not only in¢reass your earrying capacity, hut, if you will yo far enough, you will not ouly increaso your carrying capacity for that foot, but you will deerease dead-weight in still greater proportion. This ear {the sinall inetal car built of tho sams dimensions with the wooden box car of which he had been speakiug] is altogether too light a car to employ er in sufficiently largo quantities in it; hut get a truss 45 fect long and give that car a carrying capacity of at least 40 tons, aud you ean take udvautage, in almost every niember of that truss, of the ae tensile and compressive strength of steel, Testing Boiler Iron. The following is from a late report of a Government oflicial on the important matter of boiler inspection. It is evidently necessary that a positive and generally accepted rule be established for deciding this important matter. It is believed that the efforts now being made by this oftico, and supported actively by manufacturers generally, will introduce into the market iron of American manufacture for marine boiler uso, equal if not superior to that made in any part of the world, hut whatever the quality of the iron the eccentric manner of its wear under steam is not yet explained, Somo plates oxidize as soon as used ; others of identical texture and position, wear for years without material deterioration, while others agaiu, after wearing for several years without apparent damage, suddenly oxidize and are destroyed in a few months, This last condition was forcibly illustrated by the steamer Magenta, which exploded the outer shell of her steain chimney on March 23d, near Sing Sing, on the Hudson. He refers at length to the dlagentu explosion and says: Such disasters can be avoided hy frequent and careful inspection. There are laces, however, in all boilers where personal inspection is impossible and where a hydrostatic test must be relied npon. I recommend to all steamboat owners the importance of demanding sucb tests frequently, expecially when, after a season of iuactivity, work is resumed ; for experience proves that boilers deteriorate more rapidly while idle than when continuously used. He says that in all his efforts to improve the service he has had the cordial support of steamvessel owners. It is true they complain that some statutes are unjust to them while affording no advantage to the public, and they are naturally opposed to being compelled to purchase worthless patents. It is uot appropriate for him to discuss their wrongs, but he hopes justice may he done them, for ag a class they are ready to comply with every wholesome provision of the law. Of the total number of ves. sels inspected, 260 belong to the Pacitie coast, with a tonuage of 108,532; 1,820 to the Atlautic coast, with a tonnage of 466,757; 889 to Western rivers, with a tonnage of 186,932; 857 to the northern lakes, with a tonnage of 186,378, and 311 to the Gulf coast, with a tonnage of 68,831. Waar 1s SteeL?—Difficulties such as these have hitherto prevented the adoption of any of the proposed nomenclatures, says Dr. Siemens, and have decided enginecrs and manufacturers in the meautime to include, nnder the general denomination of cast-steel, all compounds consisting chiefly of iron which have been produced through fusion and are malleable. Such a general definition does not exclude from the denomination of steel materials that may not have been produced by fusion, and which may he capable of tempering, such as shear steel, blister steel and puddled steel, nor does it interfere with distiuctions between cast-steels produced by different methods, such as pot steel, Bessemer steel, or steel by fusion on the open hearth. Macaine ror Measuring SuperricraL AREA, —Mr. J. H. Williams exhibited this fall, at the Mechanics’ fair, in Boston, a very ingenious machine, which he invented, which is capable of indicating six to eight times per minute the superficial area of surfaces, however irregular, where the surface does not excecd twenty-five square feet. It can compute in less than ten seconds the sauare contecuts of a circle without reference to mathematical rules, and it is certain to find practical application in many departments of trade. It will specially be of use to leather dealers and manufacturers, for measuring exactly the superficial area of hides and skins, Tue process of Dr. de Haen for preventing incrustation in steam-boilers, which consists in the treatment of the feed-water with the proper amount of baric chloride and milk of lime, as determined by quantitative analysis, is to he employed for tbe 310 boilers of Krupp’s steel fuuu try at Essen. Improvement in SoLDERING Irons.—A novel soldering iron, the invention of M. Paquelin, was recently described before the Academy of Scierices, Paris. Its distinctive feature is a platinum receptacle, in which heat is instantaneously generated with air and petroleum vapor or air and coal-gas, Correction.—In our note last week, in regard to the wire traction rope employed by the California Street railroad, the length was given ey instead of 18,000 feet, as it sbould have ecn, Rr es HCIENTIFIC P ROGRESS. Experimental Determination of the Velocity of Light. Albert A. Micbslson, of tho U. 8. Navy, read a paper before ths American Association of Scienes, at its late meeting, on ‘‘The Experimental Detsrmination of the Velocity of Light.” Ths paper was pronouneed ons of the most important read bsfore its appropriate section, Mr. ‘M. said that but three seientists, Foucault, Fizeau, aud, more recently, Cornu, have sought to experimentally ascortain the distance of tbe sun from the earth. Foucault used the method known as that of ‘ Wheatstone’s Revolving Mirror,” the application of which was first sng. gested by Arago. Fizeauand Cornu both nsed another methed, known as that of the “‘toothedwheel.” Iu Founcault’s experiments tho distance traversed by the light was 20 meters. The result ohtained by him was 185,200 miles per second, Cornu’s stations were about 14 miles apart. The result obtained by him was 186,600 miles, which exceeds the former by 1,400 miles, The objection to Foucault’s method is that the displacement, which enters directly in formula, is very small, and therefore difficult to measure accurately. The objection to Fizeau’s is that the total disappearance of the light was necessarily uncertain. The ohject of Mr. Michelson’s experiments is to increase the displacement in the first method. This can be done in several ways: (1) By increasing the speed of the mirror; (2) by increasing the distance between the two mirrors; (3) by increasing the radius of measurement, i. e,, the distance from the revolving to the scale. In Foucault’s experiments the speed of the mirror was 400 turns per second; the radius of measnrement was about one meter, and the dis. : tance between the mirrors was about 10 meters. Thedisplacement obtained was about 0.8 millimeters. In Mr. Michelson’s experiments the speed of the mirror was but 130 turns per second, but the radius of measnrement was from 15 to 30 feet, and the distance between the mirrors was about 500 feet. The displacement obtained varied from 0.3 of an inch to 0.63 of an inch, or about 20 times that obtained by Foucault. Witha greater distance between the mirrors and a better apparatus he expected to obtain a displacemeut of two or three inches and to measure it to within’onethousandth part of an inch. Tables of observation of the velocity of light in air were given by Mr. Michelson, the mean result being 185,508 miles per second. Cast Manganese. A late number of the Chemical News says that M. Jordan has presented to the French Academy a specimen of cast metal, obtained by treatment of the ores of manganese in the blastThe composition of this metal is: furnace. Mangauese. Tron.. Carbon. Silicon. Sulphur.,. Phosphorus. . NEM: cee pienens cometeen cobedgaRoood sCoSgEoe 99.910% In snbseqnent operations the percentage of manganese has been carried as high as 87.47%. The specimen laid before the Academy had been preserved for six months without having under. gone any sensible alteration. There was noticed a considerable loss of manganese in the furnace, amounting sometimes to as much as 10%, which, with certain other facts, appcars to warraut the opinion that this metal is somewhat volatile at elevated temperatures, DENLELILDL VEGETABLE ALBINISM.—At a late meeting of the London Chemical Society, Prof. Church read a paper entitled ‘‘A Chemical Study of Vegetable Albinism,” in which numerous experiments were described and analyses presented, the conclusion arrived at by the author heing that the white leaf is parasitie upon the green. Whilst the author did not give any decided opinion as to the cause of the whiteness, he remarked that white leaves are usually weaker and thinner, and that albino cuttings cannot be ‘‘struck.”” Some attempts have been made to stimulate albino foliage, but without any decisive results, At the same meeting an interesting paper was read by Dr. Carnelly, on the ‘‘Relation betweeu the melting points of the Elements and their co-efficients of expansion.” Certain theoretical considerations led the author to the eonclusion that the co-efficient of expansiou of an element by heat would be the greater the lower its melting point. This conclusion the author has tested in the case of 31 elements, and finds that, with five exceptions, the coefficient of expansion increases as the melting point diminishes; the five exceptions are, As, Sb, Bi, Te and Sn. A table and a graphic curve aooompany the paper, which the author promises to snpplement by a communication on asimple relation existing hetween the heat evolved by a chemical reaction and the melting points of the reacting and resulting bodies, Barcenite—A New Antimonate, A heavy, nearly black minsral, which has been discovered at Hitzneo, Msxico, hy Senor Bareena, and to which his name has bsen given, has proved to be an antimonate of hitherto undescribsd charaeter, mixed witb finely-divided mercuric snlphide and antimonic acid. Heated alone hefore the outer blowpipe flams, the minoral deerepitates slightly, turns white or nearly so, and hecomes rounded (with soms difficulty) on the edges, giviug off a littls white fume ; in the reducing flame the fums becomes more abundant from reduc‘ion of mstallic antimony, followed by volatiLz: ion and burning in the outer edge of the flame, whicb is colored greenish-blue, <A firs;ment heated ina closed glass tube gives off water, metallic merecnry, black mercuric sulphide and a very little oxide of autimony ; in a tube open at botb ends the whole of the mercury is depceal in the metallic state, tbe sulphur bsing hurned off, and in a good draft of air through the tube more oxide of antimony is carried along and deposited. A well-marked white autimonial sublimate is produced by heating on charcoal, and if sodium carbonate be added the antimony is easily reduced to little metallie beads, The mincral in powdor is largely dissolved, in the oxidizing flame by borax or microcosmic salt to a clear, colorless glass, which become turbid in the reducing flame. The mineral, even when finely pulverized, is insoluble in hydrochloric or nitric acid, though this he concentrated and at the boiling temperature. It is very slightly acted on by boiling solution of ammonium sulphide. On boiling with a strong solution of sodinm hydrate, filtering, acidulating and passing in hydrosnlphuric acid, an orange precipitate is obtained in no great quantity, Hydrogen passed over the powder at a red heat easily reduces metallic antimony, which can then be attacked by acids. The quantitative analysis was made by Mr. J. R. Santos, of Guayagnil, Ecuador. He obtained; Atom’c RatiesFulphur.ccscccssecccccsscascseceseceee 2.82 088 Mercury 20.75 .104 Calcium 3.88 087 Antimony. 50.11 418 Oxygen (by 17.61 1,101 oonstitution' Water 4 lost below 130° G. we ET coouoououoocasnsoddononas Peooonosse cl 100,00 Disease or Cugstnur Trers.—The Comptes Rendus of the French Academy of Science contains an interesting note by M. Planchon on the subject of the disease at present prevailing among the chestnuts of the Cevennes, and which is probably identical with that noticed in the Basses. Pyrenees and in upper Italy. The ohief symptom visible outwardly is the decay of the extremities of the branches, sometimes one after another, and sometimes all at once, in which latter cases the tree quickly dies, thongh in others it may last in a more or less diseased state for two or three years. This gradual or sudden death of the branches, M. Planchon found to be consequent on an alteration of the roots, If these be laid bare parts of the wood and bark of the larger and middle-sized oaes are seen to be softened as if by a kind of gangrene, and a fluid exudes from their tissues which, owing to its containing tannin, forms an ink with the iron in the soil, and stains the earth round about fora considerable distance, The roots thus affected, from the smallest radicles to the largest trunks, are characterized by the constant presence of a mycelium or fungus which assumes varions forms, but which always appears snbsequently on the tronk of the tree in the same form that it was present on the underground portion of it. It generally pre. sents itself in the form of more or less ramified whitish-yellow strings, and is probably closely allied to the Agaricus melleus, which plays such havoe with fir trees, Heat-Conpuoting Power or Rooxs.—Some time ago Prof, Herschell and M. Lebonr made a series of experiments on the heat-conducting power of recks. Twenty-eight specimens were reduced to uniform circles of five inches diameter and one-half inch thick, but of six specimens that had been tried, slate plates cut parallel to the plane of cleavage transmitted the heat faster than any of the others. Where the flow became uniform the water was raised 1° Fahr, in 32 seconds; with marble, sandstone, granite and serpentine, about 39 seconds were required to raise it by the same amount. The greatest resistance to the passage of heat was offered by two specimens of shale, gray aud black, from the coal measures in the neighborhood of Newcastle, which occupied 48 to 50 seconds in raising the water one degree, or half as long again as that taken by the slate, A Quartz TrHerw erer. —Quartz, by its rotary power, M. Jou ».ré asserts in the Comptes Rendus, constitutes a tlvrinometer of extreme sensibility, fulfilling th: essential condition of every thermometer, cu uparability. When once the apparatus is fitted up it is merely needful in order to find a temperature to read off an angle, and refer to a table calenlated once for all. It may therefore be hoped that science, and even industry, may find in this new thermometer an instrument comparable to the mercurial thermometer for the simplicity of its use and the certainty of its indications. The author’s experiments extend from—20 degrees to plus 840 degrees, or perhaps 1,500 degrees.

January 4 1879.] MINING AND SCIENTIFIC PRESS. TAY. dove, 8 ed Mechanica ‘PROGRESS. Tron in Car Construction. Mueh thonght and labor has beon expended iu ths construction of railroad ears, to obviate the necessity of earrying such alargs proportion of dead weight, as has hitherto been oonsidered necessary, whether for passengers or freight ; any improvement whieh will bring ahout a favorable change in the ratio between dead load and carrying capacity must bo of proportionate value, Mr. Albert F. Hill, of Cincinnati, recently read a very interesting paper on this subject, at a meoting of the Master Car Builders’ Association, from which we cxtract as follows : Remembering that the same mechanical priuciples which govern the design aud eon. struction of a bridge hold equally good in the eonstructiou of a roof or a warcbouse floor, etc., there can bo no impropriety in cousidering a freight car-body as a perambulating bridge, or a hridge on wheels. Conceding this viow of the subject to be tenable, it will not be difficult to determinn the proper principles which should govern and the proper materials which shonld enter into the construction of freight cars. Tho tendeucy to substitute iron for wood in enginecring and architectural structuros has of late years steadily increased, until at the present tine tho wooden railroad bridge has become the exception and theiron bridgo the rule, and it will not be long before steel will supersede the iron in large spans. In our cities, iron bnild. ings or stoue buildings with iron doors supersede every year more and more brick and wood. Durability, strength, lightness and elegance of construction, as well as true economy, are the principal qualities hy which metallic structnres . P’ commend themselves. Applyiug this to car construction, I think the point of greater, in fact considerably grester, durahility will bo readily conceded, Unfortunately, no reliable or rather positive informatiou as to the life of freight cars seems obtainable, under our present system of freight service, and the continual interchange of cars over the different lines, Still, barring accidents of course, it will be safe to assume the life of a car-body to vary from eight to ten years at the most. There are some few instances of greater durahility on record, but mostly on roads which have hnt little freight traffic and less interchange over other roads. The life of a metallic car, on the other hand, may safely be estimated at from 35 to 40 years. In order to illustrate his views, Mr. Hill instituted a minute comparison between the best constrneted ordinary wooden-box freight cars, and the iron car which he proposed. He dissect_ ed the wooden car piece by piece, giviug the weight and strength of each, and then rebuilt the same car with iron wherever that metal could be introduced. We have not tbe space to gointo the particnlars of this illustration, and can only give his conclusions, which were summed up as follows: I have made a rongh calculation of the weights in that car, and I get the following results (some of these are accurately calculated and others only approximately, hut near enough for all practical purposes): I get two trusses weighing 1,680 lbs.; rolled and wrought iron, 1,760 lbs.; cast iron, 300 1bs.; wood, nearly 4,000 Ibs, Ithink I might be ahle to do it with considerably less wood yet, but I have assumed the same floor system that is in this car, and that, with the end oak timbers and buffer blocks, and some inside lining, runs up to 4,000 lhs.; and of sheet iron, 2,260 lbs., making a total of 10,000 lbs. Now this car stands thus: Approximate weight of body, 10,000 lbs.—and the weight of the car will fall withiu that; itcan be constructed with less; then for two trucks, 8,700 lbs., making a total of 18,700 lbs. for the whole car ready for use, with a carrying capacity of 20 tons. The wooden car which has served in its general dimensions and general arrangements asa model for this metallic car has a carrying capacity of 12 tons, aud a total weight of 22,000 Ibs. Granting that this wooden car when new and in good condition, can carry 15 tons, though I think that this isthe maximum that ought to be putiu that car, we have increased the carrying capacity 25% and reduced the dead weight nearly the same amount. That a metallic car constructed as this is, will effect such savings as indicated liere, is open to the ealeulation of every oue of you. There is no difficulty in calenlating these strains and iu getting the amounts of metal that are necessary for those strains. The above-mentioned of gain in weight and capacity, it will be observed, is calculated for a car of the ordinary size of wooden cars; but Mr. Hill proposes to add greatly to the length of the cars when made of iron—or what would he still hetter, of steel. His ideal metal car would he at least 45 feet long, built upon the principle of} the truss bridge. _ bridge on wheels.” ‘Where the real saving in metallic cars will Indeed he calls his car ‘‘a come in will be by Isngthening them out, and lengthening thsm out considenaly. With every foot that you add, yon will not only in¢reass your earrying capacity, hut, if you will yo far enough, you will not ouly increaso your carrying capacity for that foot, but you will deerease dead-weight in still greater proportion. This ear {the sinall inetal car built of tho sams dimensions with the wooden box car of which he had been speakiug] is altogether too light a car to employ er in sufficiently largo quantities in it; hut get a truss 45 fect long and give that car a carrying capacity of at least 40 tons, aud you ean take udvautage, in almost every niember of that truss, of the ae tensile and compressive strength of steel, Testing Boiler Iron. The following is from a late report of a Government oflicial on the important matter of boiler inspection. It is evidently necessary that a positive and generally accepted rule be established for deciding this important matter. It is believed that the efforts now being made by this oftico, and supported actively by manufacturers generally, will introduce into the market iron of American manufacture for marine boiler uso, equal if not superior to that made in any part of the world, hut whatever the quality of the iron the eccentric manner of its wear under steam is not yet explained, Somo plates oxidize as soon as used ; others of identical texture and position, wear for years without material deterioration, while others agaiu, after wearing for several years without apparent damage, suddenly oxidize and are destroyed in a few months, This last condition was forcibly illustrated by the steamer Magenta, which exploded the outer shell of her steain chimney on March 23d, near Sing Sing, on the Hudson. He refers at length to the dlagentu explosion and says: Such disasters can be avoided hy frequent and careful inspection. There are laces, however, in all boilers where personal inspection is impossible and where a hydrostatic test must be relied npon. I recommend to all steamboat owners the importance of demanding sucb tests frequently, expecially when, after a season of iuactivity, work is resumed ; for experience proves that boilers deteriorate more rapidly while idle than when continuously used. He says that in all his efforts to improve the service he has had the cordial support of steamvessel owners. It is true they complain that some statutes are unjust to them while affording no advantage to the public, and they are naturally opposed to being compelled to purchase worthless patents. It is uot appropriate for him to discuss their wrongs, but he hopes justice may he done them, for ag a class they are ready to comply with every wholesome provision of the law. Of the total number of ves. sels inspected, 260 belong to the Pacitie coast, with a tonuage of 108,532; 1,820 to the Atlautic coast, with a tonnage of 466,757; 889 to Western rivers, with a tonnage of 186,932; 857 to the northern lakes, with a tonnage of 186,378, and 311 to the Gulf coast, with a tonnage of 68,831. Waar 1s SteeL?—Difficulties such as these have hitherto prevented the adoption of any of the proposed nomenclatures, says Dr. Siemens, and have decided enginecrs and manufacturers in the meautime to include, nnder the general denomination of cast-steel, all compounds consisting chiefly of iron which have been produced through fusion and are malleable. Such a general definition does not exclude from the denomination of steel materials that may not have been produced by fusion, and which may he capable of tempering, such as shear steel, blister steel and puddled steel, nor does it interfere with distiuctions between cast-steels produced by different methods, such as pot steel, Bessemer steel, or steel by fusion on the open hearth. Macaine ror Measuring SuperricraL AREA, —Mr. J. H. Williams exhibited this fall, at the Mechanics’ fair, in Boston, a very ingenious machine, which he invented, which is capable of indicating six to eight times per minute the superficial area of surfaces, however irregular, where the surface does not excecd twenty-five square feet. It can compute in less than ten seconds the sauare contecuts of a circle without reference to mathematical rules, and it is certain to find practical application in many departments of trade. It will specially be of use to leather dealers and manufacturers, for measuring exactly the superficial area of hides and skins, Tue process of Dr. de Haen for preventing incrustation in steam-boilers, which consists in the treatment of the feed-water with the proper amount of baric chloride and milk of lime, as determined by quantitative analysis, is to he employed for tbe 310 boilers of Krupp’s steel fuuu try at Essen. Improvement in SoLDERING Irons.—A novel soldering iron, the invention of M. Paquelin, was recently described before the Academy of Scierices, Paris. Its distinctive feature is a platinum receptacle, in which heat is instantaneously generated with air and petroleum vapor or air and coal-gas, Correction.—In our note last week, in regard to the wire traction rope employed by the California Street railroad, the length was given ey instead of 18,000 feet, as it sbould have ecn,

Rr es HCIENTIFIC P ROGRESS. Experimental Determination of the Velocity of Light. Albert A. Micbslson, of tho U. 8. Navy, read a paper before ths American Association of Scienes, at its late meeting, on ‘‘The Experimental Detsrmination of the Velocity of Light.” Ths paper was pronouneed ons of the most important read bsfore its appropriate section, Mr. ‘M. said that but three seientists, Foucault, Fizeau, aud, more recently, Cornu, have sought to experimentally ascortain the distance of tbe sun from the earth. Foucault used the method known as that of ‘ Wheatstone’s Revolving Mirror,” the application of which was first sng. gested by Arago. Fizeauand Cornu both nsed another methed, known as that of the “‘toothedwheel.” Iu Founcault’s experiments tho distance traversed by the light was 20 meters. The result ohtained by him was 185,200 miles per second, Cornu’s stations were about 14 miles apart. The result obtained by him was 186,600 miles, which exceeds the former by 1,400 miles, The objection to Foucault’s method is that the displacement, which enters directly in formula, is very small, and therefore difficult to measure accurately. The objection to Fizeau’s is that the total disappearance of the light was necessarily uncertain. The ohject of Mr. Michelson’s experiments is to increase the displacement in the first method. This can be done in several ways: (1) By increasing the speed of the mirror; (2) by increasing the distance between the two mirrors; (3) by increasing the radius of measurement, i. e,, the distance from the revolving to the scale. In Foucault’s experiments the speed of the mirror was 400 turns per second; the radius of measnrement was about one meter, and the dis. : tance between the mirrors was about 10 meters. Thedisplacement obtained was about 0.8 millimeters. In Mr. Michelson’s experiments the speed of the mirror was but 130 turns per second, but the radius of measnrement was from 15 to 30 feet, and the distance between the mirrors was about 500 feet. The displacement obtained varied from 0.3 of an inch to 0.63 of an inch, or about 20 times that obtained by Foucault. Witha greater distance between the mirrors and a better apparatus he expected to obtain a displacemeut of two or three inches and to measure it to within’onethousandth part of an inch. Tables of observation of the velocity of light in air were given by Mr. Michelson, the mean result being 185,508 miles per second. Cast Manganese. A late number of the Chemical News says that M. Jordan has presented to the French Academy a specimen of cast metal, obtained by treatment of the ores of manganese in the blastThe composition of this metal is: furnace. Mangauese. Tron.... Carbon. Silicon.. Sulphur.,. Phosphorus. . NEM: cee pienens cometeen cobedgaRoood sCoSgEoe 99.910% In snbseqnent operations the percentage of manganese has been carried as high as 87.47%. The specimen laid before the Academy had been preserved for six months without having under. gone any sensible alteration. There was noticed a considerable loss of manganese in the furnace, amounting sometimes to as much as 10%, which, with certain other facts, appcars to warraut the opinion that this metal is somewhat volatile at elevated temperatures, DENLELILDL VEGETABLE ALBINISM.—At a late meeting of the London Chemical Society, Prof. Church read a paper entitled ‘‘A Chemical Study of Vegetable Albinism,” in which numerous experiments were described and analyses presented, the conclusion arrived at by the author heing that the white leaf is parasitie upon the green. Whilst the author did not give any decided opinion as to the cause of the whiteness, he remarked that white leaves are usually weaker and thinner, and that albino cuttings cannot be ‘‘struck.”” Some attempts have been made to stimulate albino foliage, but without any decisive results, At the same meeting an interesting paper was read by Dr. Carnelly, on the ‘‘Relation betweeu the melting points of the Elements and their co-efficients of expansion.” Certain theoretical considerations led the author to the eonclusion that the co-efficient of expansiou of an element by heat would be the greater the lower its melting point. This conclusion the author has tested in the case of 31 elements, and finds that, with five exceptions, the coefficient of expansion increases as the melting point diminishes; the five exceptions are, As, Sb, Bi, Te and Sn. A table and a graphic curve aooompany the paper, which the author promises to snpplement by a communication on asimple relation existing hetween the heat evolved by a chemical reaction and the melting points of the reacting and resulting bodies, Barcenite—A New Antimonate, A heavy, nearly black minsral, which has been discovered at Hitzneo, Msxico, hy Senor Bareena, and to which his name has bsen given, has proved to be an antimonate of hitherto undescribsd charaeter, mixed witb finely-divided mercuric snlphide and antimonic acid. Heated alone hefore the outer blowpipe flams, the minoral deerepitates slightly, turns white or nearly so, and hecomes rounded (with soms difficulty) on the edges, giviug off a littls white fume ; in the reducing flame the fums becomes more abundant from reduc‘ion of mstallic antimony, followed by volatiLz: ion and burning in the outer edge of the flame, whicb is colored greenish-blue, <A firs;ment heated ina closed glass tube gives off water, metallic merecnry, black mercuric sulphide and a very little oxide of autimony ; in a tube open at botb ends the whole of the mercury is depceal in the metallic state, tbe sulphur bsing hurned off, and in a good draft of air through the tube more oxide of antimony is carried along and deposited. A well-marked white autimonial sublimate is produced by heating on charcoal, and if sodium carbonate be added the antimony is easily reduced to little metallie beads, The mincral in powdor is largely dissolved, in the oxidizing flame by borax or microcosmic salt to a clear, colorless glass, which become turbid in the reducing flame. The mineral, even when finely pulverized, is insoluble in hydrochloric or nitric acid, though this he concentrated and at the boiling temperature. It is very slightly acted on by boiling solution of ammonium sulphide. On boiling with a strong solution of sodinm hydrate, filtering, acidulating and passing in hydrosnlphuric acid, an orange precipitate is obtained in no great quantity, Hydrogen passed over the powder at a red heat easily reduces metallic antimony, which can then be attacked by acids. The quantitative analysis was made by Mr. J. R. Santos, of Guayagnil, Ecuador. He obtained; Atom’c RatiesFulphur..ccscccssecccccsscascseceseceee 2.82 088 Mercury 20.75 .104 Calcium 3.88 087 Antimony.. 50.11 418 Oxygen (by 17.61 1,101 oonstitution' Water 4 lost below 130° G. we ET coouoououoocasnsoddononas Peooonosse cl 100,00 Disease or Cugstnur Trers.—The Comptes Rendus of the French Academy of Science contains an interesting note by M. Planchon on the subject of the disease at present prevailing among the chestnuts of the Cevennes, and which is probably identical with that noticed in the Basses. Pyrenees and in upper Italy. The ohief symptom visible outwardly is the decay of the extremities of the branches, sometimes one after another, and sometimes all at once, in which latter cases the tree quickly dies, thongh in others it may last in a more or less diseased state for two or three years. This gradual or sudden death of the branches, M. Planchon found to be consequent on an alteration of the roots, If these be laid bare parts of the wood and bark of the larger and middle-sized oaes are seen to be softened as if by a kind of gangrene, and a fluid exudes from their tissues which, owing to its containing tannin, forms an ink with the iron in the soil, and stains the earth round about fora considerable distance, The roots thus affected, from the smallest radicles to the largest trunks, are characterized by the constant presence of a mycelium or fungus which assumes varions forms, but which always appears snbsequently on the tronk of the tree in the same form that it was present on the underground portion of it. It generally pre. sents itself in the form of more or less ramified whitish-yellow strings, and is probably closely allied to the Agaricus melleus, which plays such havoe with fir trees, Heat-Conpuoting Power or Rooxs.—Some time ago Prof, Herschell and M. Lebonr made a series of experiments on the heat-conducting power of recks. Twenty-eight specimens were reduced to uniform circles of five inches diameter and one-half inch thick, but of six specimens that had been tried, slate plates cut parallel to the plane of cleavage transmitted the heat faster than any of the others. Where the flow became uniform the water was raised 1° Fahr, in 32 seconds; with marble, sandstone, granite and serpentine, about 39 seconds were required to raise it by the same amount. The greatest resistance to the passage of heat was offered by two specimens of shale, gray aud black, from the coal measures in the neighborhood of Newcastle, which occupied 48 to 50 seconds in raising the water one degree, or half as long again as that taken by the slate, A Quartz TrHerw erer. —Quartz, by its rotary power, M. Jou ».ré asserts in the Comptes Rendus, constitutes a tlvrinometer of extreme sensibility, fulfilling th: essential condition of every thermometer, cu uparability. When once the apparatus is fitted up it is merely needful in order to find a temperature to read off an angle, and refer to a table calenlated once for all. It may therefore be hoped that science, and even industry, may find in this new thermometer an instrument comparable to the mercurial thermometer for the simplicity of its use and the certainty of its indications. The author’s experiments extend from—20 degrees to plus 840 degrees, or perhaps 1,500 degrees.