CHEMISTRY. 



217 



For the alloy, this was ascertained compara- 

 tively ; the same weight being applied to bars 

 of the three metals and of like dimensions, 

 vrhile the index of the instrument measuring 

 the deflection showed for the bar of bras- -.-2-2 

 divisions of the scale, for that of gun metal it 

 was .15. and for that of the bronze .05. Thus, 

 the rigidity of the bronze is three times that 

 of gun metal, and about 44 times that of brass. 

 5. Ratio of expansion by heat. This also was 

 found comparatively ; and the bronze proved 

 to be slightly less expansible under increase of 

 temperature than gun metal, much less so than 

 brass. 6. Founding qualities. The bronze 

 produces admirable castings, of any required 

 dimensions. 7. Behavior tinder abrading and 

 cutting tools. The bronze does not clog the 

 file: and in the lathe or planing machine, it 

 cuts with clean, free, elastic shavings. It ap- 

 pears to .be worked in these ways with less 

 difficulty than steel. 8. Resistance to atmos- 

 pheric influences. The new alloy tarnishes 

 less readily in air than any of the metals usual- 

 ly employed for the instruments under con- 

 sideration; viz., than gun metal, brass, silver, 

 :ron, or steel. 9. Fitness to receive grad- 

 uation. The bronze rea'lily takes a very fine 

 division, and thus saves the need of inlaying 

 another metal to receive any required scale. 

 10. Elasticity. The experiments on this point 

 were comparative only; but the metal was 

 found highly elastic. 11. Fitness for being 

 made into tubes. The alloy admits of all the 

 operations requisite for the making of tubes. 

 It can be rolled into plates or hammered and 

 drawn, and is soldered either with silver or 

 brass solder. 12. Specific gravity. Of the 

 bronze here described, containing 10 per cent. 

 of aluminium, the sp. gr. is 7.6S9 : being nearly 

 that of wrought iron, and less than that of 

 either brass or gun metal. 



Generally, then, the new alloy (made with 

 .10 Al.) is in all respects superior to any metal 

 heretofore used for constructing philosophical 

 apparatus. It should be employed in the rela- 

 tive dimensions suitable for cast steel. Besides 

 its use for larger work, its hardness and groat 

 inoxidability fit it for the making of pivots, 

 axes, and bearings. Along with its other good 

 qualities, use of the alloy keeps the weight of 

 the instruments within reasonable limits. 

 Aluminium is at present extracted in England, 

 under a license from the originator of the 

 process, M. Deville, by one firm only that of 

 Bell Bros., of Newcastle. A pure copper is 

 requisite ; the best, however, that deposited by 

 electrolytic action, is too expensive : the next 

 best is the copper from the Lake Superior 

 mines. The alloy must be remelted 2 or 3 

 times : and its tenacity and strength are in 

 fact unproved by repeated remeltings (though 

 the percentage of aluminium may finally be re- 

 duced), so long as the forging qualities of the 

 alloy show improvement The present price 

 of the aluminium bronze is very high, being 

 equal to about $1.50 Federal money, per Ib. ; 



but it will doubtless fall with increasing pro- 

 duction and familiarity with its use. 



Aluminium Wire. Metallurgists had already 

 succeeded in forging aluminium, in filing, roll- 

 ing, punching, and in engraving it with any 

 sort of design. But the drawing of this metal 

 into fine wire has only recently been effected 

 by M. Garapon, of Paris. Commencing with 

 rods of about 40 inches length and i inch di- 

 ameter, he succeeds in extending these until 

 they are. if desired, reduced to the diameter of 

 a hair. This wire, which, unless acted on by 

 sulphur fumes or a very few other gases seldom 

 present, retains the perfect brightness of the 

 metal, and which has also its extreme light- 

 ness, is now employed in the making of such 

 articles as lacework, epaulets, embroideries, 

 head dresses. *fce. It is furnished at 60 or 

 more per cent, cheaper than silver wire of like 

 measurement. 



Artificial Pluirihago. Dr. Grace Calvert has 

 experimented on gray (cold-blast) cast iron, by 

 placing small cubes of this metal, about f 

 inch diameter, in weak solutions of several 

 acids, sulphuric, phosphoric, acetic, &c.. of 

 about 80 times the volume of the metal, within 

 corked bottles, renewing each acid about once 

 a month for two years. At the end of- this time 

 the action of the acetic acid was evidently still 

 going on upon the block contained in it ; but 

 this cube, which originally weighed '- 

 grammes, now weighed only 3.489 grammes, its 

 specific gravity being reduced from Y.858 to 

 2.7-jl. From Dr. Calvert's analyses of cubes of 

 iron thus treated, and then reduced to fine 

 powder in a mortar, it is shown that the iron 

 had become transformed into graphite or plum- 

 bago ; that most of the nitrogen originally in 

 the iron remains in the graphitoid substance, a 

 portion of it having gone to form ammonia in 

 the solution : that the carbon of the cast iron 

 was in like manner diminished in the grapbite, 

 a portion going to form carburetted hydrogen ; 

 and that it is sih'cium, not silica, which enters 

 into the graphite compound. Thus, finally, he 

 regards plumbago as a compound of about 91 per 

 cent, of a subcarbide of iron, with about 8i per 

 cent, of a nitride of silicium. and traces of phos- 

 phorus and sulphur. ("London Mining Jour- 

 nal." Xo. 1377.) 



Determination of Carbon in Iron. Wich de- 

 termines in a simple manner the quantity of 

 carbon in cast iron or steel, without the neces- 

 sity of pulverizing the metal. He makes the 

 iron to be analyzed the positive electrode in di- 

 lute hydrochloric acid: the metal dissolves, 

 leaving the carbon, and without evolution of 

 gas. It is necessary to regulate the strength 

 of the current by so adjusting the distance of 

 the electrodes that only the protochloride of 

 iron shall form (production of the sesquichlo- 

 ride being indicated by a yellow color of the 

 solution) : in the former case the iron does not 

 become passive, and the action goes on properly. 

 A single Bunsen's element suffices the iron to 

 be acted on being so held in a forceps of plati- 



