Volume 29 (1874) (428 pages)

October 24, 1874.] MINING AND PCLENDIGIC PRESS. 259 ii ECHANICAL rocress The Chemistry of Building Stone. Asin the construction of furnaces for their various nses, the mctallnrgist and ths glass makera consider ths refractory power of the material to be subjected to intenae hsats, 80 tha architect of thie psriod of groat conflagrations should consider, among the other requisitea uf building atone, its behavior when snbjceted to fire; itia not well enough to know that the chemical charactsr of a rock is an index to its fusihility. The manufactnrsr of fire-brick carefully selects qnartz aa pnre as may be, and fire-clay as free from lime and iron as possibls, knowing, witbuut bsing able to givs a reason, in moat cases, that theso slements vitiats ths product. They unite chemically to prodnoe fuaible compounds, with as mucb certainty aa potash or soda nnits with greass to produce soap, which is widely differsnt from either of these suhstances. Ths fate of limestencs in our great firss is well remembsred, and ws havs but to coutider ths composition to readily explain their crambling tendency at that tims. They consist mainly of carbonats of lims snd inagnssia; whon much magnssia is present they ars known as ‘‘dolomites”’—it is of this that tho large cathedrul in Nsw York is bsing constructsd. Itis as whits as any marble, and mads np of shining tabular crystals; when this or ordinary limestono ia highly heated, its carbunie acid, amonntiug to about forty-four per cant. of tha mass, is axpslled; thus, ordinary quick lims is prodnesd, and ths operation of a common lime kiln is repeated. As ths earhonate of magnssia is decomposed at a much lowsr temperature (600 deg. I.) than the carbonats of lime, stones containing it are less refraotory than thoss of pure lime—it is present in all our Illinois limestone, Sandstone is esrtainly among our best building material; it containa about ninety per cent. of silica or quartz, among the most infusibls of substances, and-small gusntitiss of iron and sluming which gives it coherence. The orperience in Chicago with the Cleveland variety sesms to confirm this; one bouse in psrtieular on the sonth sids, was mentioned by Mr. Wright, of ths American Institnte of Arehitecture, as 3 striking exampls, r Granite, like all primary rocks, is almost indostructible to ordinary atmospheric influonces, and yet sxplosions of blocks of it wers common in ths Boston firs; this may bs rsferrsd to inclosed water and the generation of steam, for, when freshly qnarried, a cubic yard contains abont thres and a half gallons of. water, which, it is safe to assnme, is nsvsr all evaporated at tha ordinary tempsrature, Brick, produet of firs itself, absorh and rstain much moisture, which, when evaporated, prodnecs a certain amount of porosity, and increases the tendency to vitrification in grsat fires; yet, like artificlalstone, all ths water they contain after hsing baked, is chemicelly and not mechanically combined, and like ths latter material has esrtainly a good record, and its value could no doubt be improved for structures by applying a coatof paint to exclnds water. Macutnze WantEeD.—A correspondent of ths New York Tribune says: Farmers generally rsquire a maehine, I think, snch as I have nsver seen or heard of, but of which Ihave especially fslt the nesd, as it will save labor and utilize forage. It is this: Say a machine that will pulyerize, or crash, ur grind, with unce handling, our corn crop;that will reduce ths entirs growth, cob, shuck and stalk, as fine as ordinary meal. After the corn is cut and putin stooks(twelve hills sqnare is the habit gensrally prevailing in the west); then as soon as the stooks are dry enongh, feed them entire into the machine, which might be similar to a grain thresher, and propsilsd by steam or horse power. My object isto place the corn stalks, as well as ths corn, in condition for the cattle to properly masticate, digest and assimilate. New Ric ror Turze-Masten Scnoonrrs.— Captain Robert B. Forbss, of Boston, has rsesntly invented a new rig for three-masted achooners, which it is eclaimsd, can also benssd for propellers rsquiring considsrable sail, but which ia particnlarly designed for the firstnamed class of vessels. With respect to the economy of ths rig, Captain Forbes estimates & savingof several hundred dollars in the size of the masts, the abssnes of large hoops and blocks, heevy gaffe, and in the canvas, inasmuoh as only the two lower stay saile and the jib nged be of the heavieet. The booms being unincumbered hy the sails when furled, can be nssd as cargo derrieks. The eails all furling to the masts are more out of the way in port; mugre easily dtisd and kept clean and mors durable. Removine Trees By STEaAM.—A method of removing treea by dragging them out by the roote by a steam-engine, has been eycccesfully introduced on the Duke of Sutherland’s estate in Scotland. The engine, (a¢welve-horse power, being one gsnerally need for. plowing,) was placed in a field about 150 yarde distant from the trees; a chain was passed round each at eome distance from the ground, and the engine being then eet on; the tree was tumbled over and dragged out with a lerge ball of earth adhering to the roots. In this way 300 tress, of from six to 12 inches diamstsr were removed in a few houre; but trees of three feet diameter have bsen dragged out by the same meant, Improving Brittle tron. No doubt many observing persons must havo noticed in soms railways long in nse, that the iron scales and is shivered liks a wood track or rail. These scales fritter away ths strength and aubstance uf the rail, and render tbs movement of the cars irregular and subject to accidents, comstimes endangering lifa and limb. We ars reminded of this hy ths lats frightful aceident on ons of our railways. Bnt a short time since an iron transom or support ina building in Louisville, Kentucky, broks and the bnilding gave way, endaugering tho lives of several persons engaged on the building. Though this was of cast iron, still ths samead. monitiun follows to havo onr works and railways of tougher and more durable matorial. Inthe Bessemer process many impuritics whicb, with an sxcess of carhonu, ars the causes of the brittleness of muuy kinds of cast-iron, ars burned ont by moans of the air-hisst psssfing foroibly throngh ths melted iron. Qaery: Can not cast-iron in general be greatly improvsd when, while inthe mslted condition, air is blown throngh it? Witbout going to the extcnt of decarhonization and purification, as is done in the Bessemsr prooess, it is certein that evsry eanldron with melted iron, before being poured into the moulds, may easily bs submitted tu acertain limitsd amount of air-blast, snd this hy simpler means than are used in the Bessemsr works, requiring a highly expensivs plant. Suoh a proceeding would bs sspscially nssfat in ths produotion of a snpsrior mallsable oast-irou in such localities as Indiana and Missouri, whsre the necsssary materials, coal and iron ore, are in such excsptional states of purity. —Am. Manufacturer. ° New AppiicaTion oF ELEcTRiciry on Rariroaps.—The Frenoh have lately introduced a system by which a stationary electric battery is made subssrvisnt to blow ths whistle of an approaching locomotive, in case the road is not clsar, without the engineer having to give any attention to it. Such an srrangement is, of conrss, sxcesdingly valuabls at night, and espeoially during a fog, when signals can not be seen at a distance. Itis the reverse of the system introduced on our Hndson river railroad, by which 'svery approaching locomotive sets a ststionary slectro-magnetic alarm hell at the depot in motion. In ths French system referred to, the obstruction at the depot starts ths stsam whistle on every approaching locomotive when ths train is still far enough away to slacken speed and stop. It has now been in successful operation for a ysar on the Jine of the Northsrn company of France, informing the engineer whether the way is clear or not. The signel tendsr turns a disk and ssnds an electric current in the direction of the coming train to a har placed between ths rails; when the engins rsaches the spot, a metel brush, placed betwesn ths wheels, sweeps the bar; the current passes to ths engins, and, hy means of an electro-magnet, presses upon a lever which opens the steam whistls, thus making it blow automstically. Measvrine THE Stars.—A method of deter. mining the apparent diameter of ths stars, devissd by M. Stephan of Marseillss, appears to bs very ingenious, tosaythelesst. If, throngh an excellent telescope, a star, whose angular diameter is really nothing, be viewed with a sufficient high magnifying power, the image is seen to be a bright spot surronmded hy the concentric rings of light and shade which erecalled diffraction rings. Now, it has been shown by M. Fizeau that these rings, if, of extreme faintnsss and distance from the central spot, can only bs formsd when the angular diameter of the source of light is nsarly insensible; and, following out this very unique suggsstion, M. Fizeau has applied to the Marseilles telescope a diaphragm having two apertures for the observation of the fringes produced by the intsrference. Ifthe star has a certsin diameter, the fringss will diseppear altogether; and if its diameter is zsro, the distance of the fringes will vary with the distances of the two apertures in the diaphragm. Among the results of M. Stephan’s investigation in this direction, is the interesting fact that Sirius appears to have a measureable diamster. IMPROVEMENTS IN Punntinc.—M. Masien, Lonvroil, near Maubeuge, Nord, France, hss patented in Francs and Bslgium a new furnace. The form is nearly conicel, the air bsing freely admitted through apsrtures made sll along the face of the furnace at the hight of thebars. The heat is made to concentrate itself in the sole of the fnrnace, aceslerating the puddling. The puddler is exposed to much lsss heat thanin the caee of the equare fnrnaces; and it is seid to be able to make from eight to nine charges of good row iron, No, 2, in 12 hours, with a consumption of 1,400 to 1,500 kilogs., an economy set down at 300 to 400 kilogs., of ooal per ton of rawiron. The following are given as results of experience: With the Mesian furuace, a ton of good No. 2 raw meterial was produced with 1,050 kilogs. of coal, the ordinary furnace requiring 1,300 kilogs. A ton of extra strong iron was produced in the new furnace with 1,252 kilogs. of coal, ths old furnacs consuming 1,502 Kiloge. Tretiurtom.—The aalte of tsliurium have the propsrty of imparting to the perspiratiou a most offensive odor. It iseaid that Professor Bunsen, who expsrimented on his own person, was compelled to absent himeelf from eociety for four weeks on this account; itig supposed that tellurinm will never be ussd extensively as a medicine. Merenastcan Vinaation Retarprxc Roat.— At the recent ineeting of tha American Association for ths advanesinent of Science, Prof. 8.5. Haldeman, of Harrisburg, read a paper with the abovo title, of which the following is a brief ubstract: When railroad bars ars piled beside a read they soon become rusted, while thoss forming the track are but little subject to oxidation; and whon a rsin of some honrs’ duration falls upon rails when in a state of rest, ag upen Sundays, when trains do not run, thsy soon eshibit rnst. This would seem to indicate that in chemical combination mechanical vibrations may interfsre witb the molecular arrangewent of tbe elements. The accuracy of theas enaual observation sbould, howover, be subjected to the test of srperimsnt. In tbe diseussion which followed this brisf communication it was suggested tbst possihly ths oil smployed upon locomotives might bs moro or less spread ina thin film over rails in use, and thus prevent their oxidation, This view -was eainestly cambattod by otber speakers. Prof. Van der Weyds was quite certain that the suggestion of Prof. Haldeman bore reference to a factin physies. Molecnlar vibrations tended to prevent rast. A saw hung np, unused, would soou becoms rusty; if nsed, would keep pea This was a genersl] experisnes with tools. + ¢ ANewandintensely white light has lately been invented and exhibited by Mr. Wm. Day, of Ohio. A thin ribbon of carbon is suspended betwesn two platinum poles, and covered by a glohe contaiuing dry carbonic acid gas. The ribbon receives an electric enrrsnt from a battery, aud while in the atmosphsre of the gas becomes brilliantly incandescent. Ths carbon is not consumed, and the light is said to be perfectly constant. Ths msthod was invented hy Professor Osborn, of Miami University, who at first thonght it necessary to use very thin strips of carbon, but the light is now produced with much larger ribbons and with little combustion. The hsat generated has nsver, as yet, broksn the smal! glass glohs containing the ribbon. This light being constant, and not requiring the combustion of carhon, may provs mnech mors useful to scientific lectnrers than ths ordinsry electrio or oxyhydrogen lights, both of which are troublesome to handle. Mercnanican Treatment or Mztau. — It sometimes happsns that by centering, etc., tbe interior diameter of a tirs becomes so mnch too large that it will not fit the wheel. This defect may be corrected, acoording to a German plao, by heating the tire red hot, and holding it in that condition half immersed in celd water until cold, then heating again red hot, and immersing the other half in ths sams way. In the first opsration, the unimmsrsed hot portion must coutract with ths portion rapidly cooled, with a corrssponding condensation of material, and consequent permanent diminution of diameter, and, in ths second operation, a similar effect is producsd on the other half. This rssort is not confinsd to tires alone—an instance being recorded where a ring of DGessemer steel, to be used as a flange ring, had bsen entirely missbaped by an inexperienced workmau, and was drawn into shape by heating fifteen times, and cooling different portions. ScienTiFic PRoaress. Prizes Offered by the Dutch Society of Science. Ths Dutch Society ot Science, which held its one hundred and twsnty-secoud general meeting at Harlem on the 16th of Mey, offered prizes for the following questions, all papers to be handed in by January 1st, 1876: 1. Exact researches on the solvent power of water, and of watsr charged with csrbonic acid, upon gypsum, limsstone and dolomite, at different pressures and temperatures, and in case of the simultaneous presence of common salt, and of other salts extensively distributed in nature. 2. Similar rsssarehes on ths solvent power of water, and water charged with carbonic acid upon silica, and the common naturel silicates, under the same circnmstances. 8. Nsw researches on the structure of ths kidneys of mammifsrous animals. It appears to result from recent researches that the psptonss of the different albuminoid matters are mixtures of subetences partially known and partially unknown. Required, a critical examination of these researches, sup‘plemented by personal investigations on the same question. . a 5. Exact determination, in Weber’s unities, of the resistance of 2 colnmn’ of mercury of 2 meter in hight, and of a squere millimeter in section. 6. Improved experimsntal determination of the relations hstween the two kinde of experimental unities, the slectro-magnetic and electro-statio, 7. Nsw experiments on the influencs of preesure upon chemical action. Sorentivid anp Mzonanioan .Prizes.—The Academy of Sciences of Berlin offers a prize of $200, payable in July, 1876, for the hest easy rocording experimente aa to whether changes in the hardness and friability of steel are dus to chemical or physical causes, or to both. Passenger Transit. Tbe American Society of Civil Eugincers bas appointed a comunittce of fivs to investigats the necessary conditions of success, and to recommend plans for—J'irst: Ths best means of pane transit for passengers, and Secend: Ths best aud cheapest methods of delivering, storing and distributing goods and freight in and about tho oity of New York; withiustructions to examine plans, and to receive such snggestions ns parties interested in the matter may chooso to offer, and to report on or befora the first dny of Dseember, 1874. The committos and the Society solicit contnbntions aod snggestions of valus on the abovs subjacts. Dus credit will be given for allaid rendsred to ths committes. In referriug to plans proposed to accomplish these objects, it is particnlarly desired to ascertain accuratoly— Ist. The ronte and location proposed, and tbs rsssons therefor. q 2d, Tbe character of structnre proposed in various parts of the city. 3d__A closs sstimate of ths eost in detail. Ths committe consists of the followiug gentlemsn: O. Chanute, M. N. Forncy, Issac C. Buckhout, Charles K. Graham and Francis Collingwood. We heartily recommend the subject to such of onr readers as fsol an interest in these very impdértint subjects. Communicatious should be addressed to G. Leverich, 63 William street, Nsw York. . In connection with this latter proposition, we would givs the following as the result of the prizs offered some two years ago for improvemeut in the navigation of canals: The Baxter line bave now six steam caual boats mnuing bstweeu New York city and Buffalo. They have a carrying capscity of about 200 tong each, and make the trip ench way in about six days. Allowing for one day at each terminus, tbe round trip is msds in fourteen days or two trips a montb. This is double tbe spsed of the horse hoats, tbey averaging hut ons trip a month. During the winter these boats will rnn on some of the southern canals. They are already playing a very important part in solving the publan of cheap transportatiou. Constants or Natury.—Ths Smithsonian Institution has in view the publication of a ssries of tables of ‘‘Constants of Nature,’’ such as tbeatomic weight of hodies, specific gravity, expansion, elasticity, specific and latsnt heat, conducting power, melting and hoiling point, weight of different gases, liquids, and solids, crystalline form, strength of different materinls index of refraction and dispersion, polarizing angle, velocity of sound, of projectiles, of winds, of electricity, of light, of flight of birds, spsed of animals, etc. The value of such a work in aiding original investigation, as wellas in the application of science to the useful arts, can scarcely be overestimated. To cerry out thé idea fully, howevsr, will require much labor and ths united efforts of different institutions, and individuals dsvoted to special lines of research. Hence that Society, through its Secretary, Prof. Henry, has issued a circular soliciting ths co-operatiou in this work of scieutific individuals and societies geuerally. Since the different constants are to he‘carefully tabulated, even a single determination of any one constant for sny onc body may prove to be of great value by supplying some importent omission in a series. Every contributor will bs credited with his determinations, when published. No more important contribution to the sum of knowledge and to the advancement of science, both practical and theoretical, cen well be imagined than ths determiuation of some of these constants. OrystauLizen Bismota.—It is well known thst hismath, when pure, forms heautiful groups of very perfect crystals, which exhibit a splendid play of colors, and resemble somewhat a huge fortification. In order, says, Beettger, to ohtain perfect crystals, the impure bismuth of commerce should he fused for half an hour with the twentieth part of its weight of nitrate of potash in a small porcelain crucible over a simple gas-burner, the mass being atirred occssionally with a clay pips-stem. The slag must then be carefully rsmoved, and the metal ponrsd into a small wooden box which is psrfsctly dry. It is left theu uutil the greater part of the metal which touches ths sides of the box becomes solid—only the center of the mass rsmaining Huid. By carefully turning the box, the fluid portion can be ponred into an iron dish. By sawing through the mass wbich has cooled in the hox, a group of silver-white crystals will be found, some of which will be perfect octehedra. é, A Raitway Lame Wanten.—The London Society of Arts offers its gold medal or $105 to the.inventor of an improved lamp or means of illumination suitahle for railway passenger carriages that shall prodace a good, clear, steady, durable and safe light. it must be simple in construction, and capable of being readily cleaned and repeired, In judging the merits, cost will be taken into consideration. Car Tart Parer.—To the list of waste products that are now are now becoming utilized ie to be added the common ‘“‘cat tail,’’ a plant that abounds in many marshy districts toa very great extent. M, Dupont prepares the fibre by boiling the cnt and dried leaves for several houre in an alkaline solution, and then pressing hetween rollers and washing. Thus prepared it is valued at from $7 to $8 per hnndred weight.

October 24, 1874.] MINING AND PCLENDIGIC PRESS. 259 ii ECHANICAL rocress The Chemistry of Building Stone. Asin the construction of furnaces for their various nses, the mctallnrgist and ths glass makera consider ths refractory power of the material to be subjected to intenae hsats, 80 tha architect of thie psriod of groat conflagrations should consider, among the other requisitea uf building atone, its behavior when snbjceted to fire; itia not well enough to know that the chemical charactsr of a rock is an index to its fusihility. The manufactnrsr of fire-brick carefully selects qnartz aa pnre as may be, and fire-clay as free from lime and iron as possibls, knowing, witbuut bsing able to givs a reason, in moat cases, that theso slements vitiats ths product. They unite chemically to prodnoe fuaible compounds, with as mucb certainty aa potash or soda nnits with greass to produce soap, which is widely differsnt from either of these suhstances. Ths fate of limestencs in our great firss is well remembsred, and ws havs but to coutider ths composition to readily explain their crambling tendency at that tims. They consist mainly of carbonats of lims snd inagnssia; whon much magnssia is present they ars known as ‘‘dolomites”’—it is of this that tho large cathedrul in Nsw York is bsing constructsd. Itis as whits as any marble, and mads np of shining tabular crystals; when this or ordinary limestono ia highly heated, its carbunie acid, amonntiug to about forty-four per cant. of tha mass, is axpslled; thus, ordinary quick lims is prodnesd, and ths operation of a common lime kiln is repeated. As ths earhonate of magnssia is decomposed at a much lowsr temperature (600 deg. I.) than the carbonats of lime, stones containing it are less refraotory than thoss of pure lime—it is present in all our Illinois limestone, Sandstone is esrtainly among our best building material; it containa about ninety per cent. of silica or quartz, among the most infusibls of substances, and-small gusntitiss of iron and sluming which gives it coherence. The orperience in Chicago with the Cleveland variety sesms to confirm this; one bouse in psrtieular on the sonth sids, was mentioned by Mr. Wright, of ths American Institnte of Arehitecture, as 3 striking exampls, r Granite, like all primary rocks, is almost indostructible to ordinary atmospheric influonces, and yet sxplosions of blocks of it wers common in ths Boston firs; this may bs rsferrsd to inclosed water and the generation of steam, for, when freshly qnarried, a cubic yard contains abont thres and a half gallons of. water, which, it is safe to assnme, is nsvsr all evaporated at tha ordinary tempsrature, Brick, produet of firs itself, absorh and rstain much moisture, which, when evaporated, prodnecs a certain amount of porosity, and increases the tendency to vitrification in grsat fires; yet, like artificlalstone, all ths water they contain after hsing baked, is chemicelly and not mechanically combined, and like ths latter material has esrtainly a good record, and its value could no doubt be improved for structures by applying a coatof paint to exclnds water. Macutnze WantEeD.—A correspondent of ths New York Tribune says: Farmers generally rsquire a maehine, I think, snch as I have nsver seen or heard of, but of which Ihave especially fslt the nesd, as it will save labor and utilize forage. It is this: Say a machine that will pulyerize, or crash, ur grind, with unce handling, our corn crop;that will reduce ths entirs growth, cob, shuck and stalk, as fine as ordinary meal. After the corn is cut and putin stooks(twelve hills sqnare is the habit gensrally prevailing in the west); then as soon as the stooks are dry enongh, feed them entire into the machine, which might be similar to a grain thresher, and propsilsd by steam or horse power. My object isto place the corn stalks, as well as ths corn, in condition for the cattle to properly masticate, digest and assimilate. New Ric ror Turze-Masten Scnoonrrs.— Captain Robert B. Forbss, of Boston, has rsesntly invented a new rig for three-masted achooners, which it is eclaimsd, can also benssd for propellers rsquiring considsrable sail, but which ia particnlarly designed for the firstnamed class of vessels. With respect to the economy of ths rig, Captain Forbes estimates & savingof several hundred dollars in the size of the masts, the abssnes of large hoops and blocks, heevy gaffe, and in the canvas, inasmuoh as only the two lower stay saile and the jib nged be of the heavieet. The booms being unincumbered hy the sails when furled, can be nssd as cargo derrieks. The eails all furling to the masts are more out of the way in port; mugre easily dtisd and kept clean and mors durable. Removine Trees By STEaAM.—A method of removing treea by dragging them out by the roote by a steam-engine, has been eycccesfully introduced on the Duke of Sutherland’s estate in Scotland. The engine, (a¢welve-horse power, being one gsnerally need for. plowing,) was placed in a field about 150 yarde distant from the trees; a chain was passed round each at eome distance from the ground, and the engine being then eet on; the tree was tumbled over and dragged out with a lerge ball of earth adhering to the roots. In this way 300 tress, of from six to 12 inches diamstsr were removed in a few houre; but trees of three feet diameter have bsen dragged out by the same meant, Improving Brittle tron. No doubt many observing persons must havo noticed in soms railways long in nse, that the iron scales and is shivered liks a wood track or rail. These scales fritter away ths strength and aubstance uf the rail, and render tbs movement of the cars irregular and subject to accidents, comstimes endangering lifa and limb. We ars reminded of this hy ths lats frightful aceident on ons of our railways. Bnt a short time since an iron transom or support ina building in Louisville, Kentucky, broks and the bnilding gave way, endaugering tho lives of several persons engaged on the building. Though this was of cast iron, still ths samead. monitiun follows to havo onr works and railways of tougher and more durable matorial. Inthe Bessemer process many impuritics whicb, with an sxcess of carhonu, ars the causes of the brittleness of muuy kinds of cast-iron, ars burned ont by moans of the air-hisst psssfing foroibly throngh ths melted iron. Qaery: Can not cast-iron in general be greatly improvsd when, while inthe mslted condition, air is blown throngh it? Witbout going to the extcnt of decarhonization and purification, as is done in the Bessemsr prooess, it is certein that evsry eanldron with melted iron, before being poured into the moulds, may easily bs submitted tu acertain limitsd amount of air-blast, snd this hy simpler means than are used in the Bessemsr works, requiring a highly expensivs plant. Suoh a proceeding would bs sspscially nssfat in ths produotion of a snpsrior mallsable oast-irou in such localities as Indiana and Missouri, whsre the necsssary materials, coal and iron ore, are in such excsptional states of purity. —Am. Manufacturer. ° New AppiicaTion oF ELEcTRiciry on Rariroaps.—The Frenoh have lately introduced a system by which a stationary electric battery is made subssrvisnt to blow ths whistle of an approaching locomotive, in case the road is not clsar, without the engineer having to give any attention to it. Such an srrangement is, of conrss, sxcesdingly valuabls at night, and espeoially during a fog, when signals can not be seen at a distance. Itis the reverse of the system introduced on our Hndson river railroad, by which 'svery approaching locomotive sets a ststionary slectro-magnetic alarm hell at the depot in motion. In ths French system referred to, the obstruction at the depot starts ths stsam whistle on every approaching locomotive when ths train is still far enough away to slacken speed and stop. It has now been in successful operation for a ysar on the Jine of the Northsrn company of France, informing the engineer whether the way is clear or not. The signel tendsr turns a disk and ssnds an electric current in the direction of the coming train to a har placed between ths rails; when the engins rsaches the spot, a metel brush, placed betwesn ths wheels, sweeps the bar; the current passes to ths engins, and, hy means of an electro-magnet, presses upon a lever which opens the steam whistls, thus making it blow automstically. Measvrine THE Stars.—A method of deter. mining the apparent diameter of ths stars, devissd by M. Stephan of Marseillss, appears to bs very ingenious, tosaythelesst. If, throngh an excellent telescope, a star, whose angular diameter is really nothing, be viewed with a sufficient high magnifying power, the image is seen to be a bright spot surronmded hy the concentric rings of light and shade which erecalled diffraction rings. Now, it has been shown by M. Fizeau that these rings, if, of extreme faintnsss and distance from the central spot, can only bs formsd when the angular diameter of the source of light is nsarly insensible; and, following out this very unique suggsstion, M. Fizeau has applied to the Marseilles telescope a diaphragm having two apertures for the observation of the fringes produced by the intsrference. Ifthe star has a certsin diameter, the fringss will diseppear altogether; and if its diameter is zsro, the distance of the fringes will vary with the distances of the two apertures in the diaphragm. Among the results of M. Stephan’s investigation in this direction, is the interesting fact that Sirius appears to have a measureable diamster. IMPROVEMENTS IN Punntinc.—M. Masien, Lonvroil, near Maubeuge, Nord, France, hss patented in Francs and Bslgium a new furnace. The form is nearly conicel, the air bsing freely admitted through apsrtures made sll along the face of the furnace at the hight of thebars. The heat is made to concentrate itself in the sole of the fnrnace, aceslerating the puddling. The puddler is exposed to much lsss heat thanin the caee of the equare fnrnaces; and it is seid to be able to make from eight to nine charges of good row iron, No, 2, in 12 hours, with a consumption of 1,400 to 1,500 kilogs., an economy set down at 300 to 400 kilogs., of ooal per ton of rawiron. The following are given as results of experience: With the Mesian furuace, a ton of good No. 2 raw meterial was produced with 1,050 kilogs. of coal, the ordinary furnace requiring 1,300 kilogs. A ton of extra strong iron was produced in the new furnace with 1,252 kilogs. of coal, ths old furnacs consuming 1,502 Kiloge. Tretiurtom.—The aalte of tsliurium have the propsrty of imparting to the perspiratiou a most offensive odor. It iseaid that Professor Bunsen, who expsrimented on his own person, was compelled to absent himeelf from eociety for four weeks on this account; itig supposed that tellurinm will never be ussd extensively as a medicine. Merenastcan Vinaation Retarprxc Roat.— At the recent ineeting of tha American Association for ths advanesinent of Science, Prof. 8.5. Haldeman, of Harrisburg, read a paper with the abovo title, of which the following is a brief ubstract: When railroad bars ars piled

beside a read they soon become rusted, while thoss forming the track are but little subject to oxidation; and whon a rsin of some honrs’ duration falls upon rails when in a state of rest, ag upen Sundays, when trains do not run, thsy soon eshibit rnst. This would seem to indicate that in chemical combination mechanical vibrations may interfsre witb the molecular arrangewent of tbe elements. The accuracy of theas enaual observation sbould, howover, be subjected to the test of srperimsnt. In tbe diseussion which followed this brisf communication it was suggested tbst possihly ths oil smployed upon locomotives might bs moro or less spread ina thin film over rails in use, and thus prevent their oxidation, This view -was eainestly cambattod by otber speakers. Prof. Van der Weyds was quite certain that the suggestion of Prof. Haldeman bore reference to a factin physies. Molecnlar vibrations tended to prevent rast. A saw hung np, unused, would soou becoms rusty; if nsed, would keep pea This was a genersl] experisnes with tools. + ¢ ANewandintensely white light has lately been invented and exhibited by Mr. Wm. Day, of Ohio. A thin ribbon of carbon is suspended betwesn two platinum poles, and covered by a glohe contaiuing dry carbonic acid gas. The ribbon receives an electric enrrsnt from a battery, aud while in the atmosphsre of the gas becomes brilliantly incandescent. Ths carbon is not consumed, and the light is said to be perfectly constant. Ths msthod was invented hy Professor Osborn, of Miami University, who at first thonght it necessary to use very thin strips of carbon, but the light is now produced with much larger ribbons and with little combustion. The hsat generated has nsver, as yet, broksn the smal! glass glohs containing the ribbon. This light being constant, and not requiring the combustion of carhon, may provs mnech mors useful to scientific lectnrers than ths ordinsry electrio or oxyhydrogen lights, both of which are troublesome to handle. Mercnanican Treatment or Mztau. — It sometimes happsns that by centering, etc., tbe interior diameter of a tirs becomes so mnch too large that it will not fit the wheel. This defect may be corrected, acoording to a German plao, by heating the tire red hot, and holding it in that condition half immersed in celd water until cold, then heating again red hot, and immersing the other half in ths sams way. In the first opsration, the unimmsrsed hot portion must coutract with ths portion rapidly cooled, with a corrssponding condensation of material, and consequent permanent diminution of diameter, and, in ths second operation, a similar effect is producsd on the other half. This rssort is not confinsd to tires alone—an instance being recorded where a ring of DGessemer steel, to be used as a flange ring, had bsen entirely missbaped by an inexperienced workmau, and was drawn into shape by heating fifteen times, and cooling different portions. ScienTiFic PRoaress. Prizes Offered by the Dutch Society of Science. Ths Dutch Society ot Science, which held its one hundred and twsnty-secoud general meeting at Harlem on the 16th of Mey, offered prizes for the following questions, all papers to be handed in by January 1st, 1876: 1. Exact researches on the solvent power of water, and of watsr charged with csrbonic acid, upon gypsum, limsstone and dolomite, at different pressures and temperatures, and in case of the simultaneous presence of common salt, and of other salts extensively distributed in nature. 2. Similar rsssarehes on ths solvent power of water, and water charged with carbonic acid upon silica, and the common naturel silicates, under the same circnmstances. 8. Nsw researches on the structure of ths kidneys of mammifsrous animals. It appears to result from recent researches that the psptonss of the different albuminoid matters are mixtures of subetences partially known and partially unknown. Required, a critical examination of these researches, sup‘plemented by personal investigations on the same question. . a 5. Exact determination, in Weber’s unities, of the resistance of 2 colnmn’ of mercury of 2 meter in hight, and of a squere millimeter in section. 6. Improved experimsntal determination of the relations hstween the two kinde of experimental unities, the slectro-magnetic and electro-statio, 7. Nsw experiments on the influencs of preesure upon chemical action. Sorentivid anp Mzonanioan .Prizes.—The Academy of Sciences of Berlin offers a prize of $200, payable in July, 1876, for the hest easy rocording experimente aa to whether changes in the hardness and friability of steel are dus to chemical or physical causes, or to both. Passenger Transit. Tbe American Society of Civil Eugincers bas appointed a comunittce of fivs to investigats the necessary conditions of success, and to recommend plans for—J'irst: Ths best means of pane transit for passengers, and Secend: Ths best aud cheapest methods of delivering, storing and distributing goods and freight in and about tho oity of New York; withiustructions to examine plans, and to receive such snggestions ns parties interested in the matter may chooso to offer, and to report on or befora the first dny of Dseember, 1874. The committos and the Society solicit contnbntions aod snggestions of valus on the abovs subjacts. Dus credit will be given for allaid rendsred to ths committes. In referriug to plans proposed to accomplish these objects, it is particnlarly desired to ascertain accuratoly— Ist. The ronte and location proposed, and tbs rsssons therefor. q 2d, Tbe character of structnre proposed in various parts of the city. 3d__A closs sstimate of ths eost in detail. Ths committe consists of the followiug gentlemsn: O. Chanute, M. N. Forncy, Issac C. Buckhout, Charles K. Graham and Francis Collingwood. We heartily recommend the subject to such of onr readers as fsol an interest in these very impdértint subjects. Communicatious should be addressed to G. Leverich, 63 William street, Nsw York. . In connection with this latter proposition, we would givs the following as the result of the prizs offered some two years ago for improvemeut in the navigation of canals: The Baxter line bave now six steam caual boats mnuing bstweeu New York city and Buffalo. They have a carrying capscity of about 200 tong each, and make the trip ench way in about six days. Allowing for one day at each terminus, tbe round trip is msds in fourteen days or two trips a montb. This is double tbe spsed of the horse hoats, tbey averaging hut ons trip a month. During the winter these boats will rnn on some of the southern canals. They are already playing a very important part in solving the publan of cheap transportatiou. Constants or Natury.—Ths Smithsonian Institution has in view the publication of a ssries of tables of ‘‘Constants of Nature,’’ such as tbeatomic weight of hodies, specific gravity, expansion, elasticity, specific and latsnt heat, conducting power, melting and hoiling point, weight of different gases, liquids, and solids, crystalline form, strength of different materinls index of refraction and dispersion, polarizing angle, velocity of sound, of projectiles, of winds, of electricity, of light, of flight of birds, spsed of animals, etc. The value of such a work in aiding original investigation, as wellas in the application of science to the useful arts, can scarcely be overestimated. To cerry out thé idea fully, howevsr, will require much labor and ths united efforts of different institutions, and individuals dsvoted to special lines of research. Hence that Society, through its Secretary, Prof. Henry, has issued a circular soliciting ths co-operatiou in this work of scieutific individuals and societies geuerally. Since the different constants are to he‘carefully tabulated, even a single determination of any one constant for sny onc body may prove to be of great value by supplying some importent omission in a series. Every contributor will bs credited with his determinations, when published. No more important contribution to the sum of knowledge and to the advancement of science, both practical and theoretical, cen well be imagined than ths determiuation of some of these constants. OrystauLizen Bismota.—It is well known thst hismath, when pure, forms heautiful groups of very perfect crystals, which exhibit a splendid play of colors, and resemble somewhat a huge fortification. In order, says, Beettger, to ohtain perfect crystals, the impure bismuth of commerce should he fused for half an hour with the twentieth part of its weight of nitrate of potash in a small porcelain crucible over a simple gas-burner, the mass being atirred occssionally with a clay pips-stem. The slag must then be carefully rsmoved, and the metal ponrsd into a small wooden box which is psrfsctly dry. It is left theu uutil the greater part of the metal which touches ths sides of the box becomes solid—only the center of the mass rsmaining Huid. By carefully turning the box, the fluid portion can be ponred into an iron dish. By sawing through the mass wbich has cooled in the hox, a group of silver-white crystals will be found, some of which will be perfect octehedra. é, A Raitway Lame Wanten.—The London Society of Arts offers its gold medal or $105 to the.inventor of an improved lamp or means of illumination suitahle for railway passenger carriages that shall prodace a good, clear, steady, durable and safe light. it must be simple in construction, and capable of being readily cleaned and repeired, In judging the merits, cost will be taken into consideration. Car Tart Parer.—To the list of waste products that are now are now becoming utilized ie to be added the common ‘“‘cat tail,’’ a plant that abounds in many marshy districts toa very great extent. M, Dupont prepares the fibre by boiling the cnt and dried leaves for several houre in an alkaline solution, and then pressing hetween rollers and washing. Thus prepared it is valued at from $7 to $8 per hnndred weight.