MECHANICS AND USEFUL ARTS. 65 



than by the older method, and finished bars, rails, plates, etc., 

 can be produced by the same heat that melts the ores into crude 

 or cast iron. The plan, now in successful operation in Austria, is 

 soon to be largely introduced into this country. 



Testing Bessemer Steel for Carbon. This is done in the follow- 

 ing simple manner by the English manufacturers. A standard 

 piece of steel is kept on hand, in which the proportion of carbon 

 has been accurately determined by chemical analysis. A few fil- 

 ings from this are dissolved in nitric acid of a certain gravity and 

 kept in a phial. The shade of brown given to nitric acid by a cer- 

 tain proportion of carbon is very exact and uniform, and hence, 

 a specimen of exact weight being taken from each charge and 

 dissolved in half the standard weight of acid, and the solution 

 then diluted with water until it reaches the exact color of the 

 standard solution, the comparative specific gravity of the two so- 

 lutions will determine the proportion of carbon in the specimen, 

 to a hundredth of one per cent. There is not the slightest ap- 

 preciable variation of ingredients, throughout different parts of 



the same charge. 



SILICIUM IN IRON. 



Dr. List, a German, has lately made a series of analyses respect- 

 ing the reaction of the silicium in pig-iron during puddling and 

 other refining processes. These analyses, like most of the other 

 similar ones made during the last few years, prove that, under 

 normal conditions, silicium is one of the most easily removable 

 constituents of pig-iron. That this removal of the silicium is 

 effected by oxidation, is shown by the fact that several varieties 

 of pig-iron were found by List not to have lost any silicium when 

 melted down in a cupola furnace. Calvert and Johnson found 

 that pig-iron containing 2.72 per cent, silicium, contained only 

 0. 197 l per cent, when melted down, after an hour in a puddling 

 furnace. Similarly, List found that the 1.92 per cent, of silicium, 

 contained in a gray Nassau pig-iron, had diminished to 0.29 by 

 the time the latter had begun to melt. In two other cases, where 

 the process lasted a little longer, the silicium had diminished 

 88.83 and 96.6 per cent. Altogether it appears that pig-iron may 

 contain up to 3 percent, of silicium without disturbing the puddling 

 process. Frm pig-iron containing more than 3 per cent, it would 

 be difficult, if not impossible, to obtain good puddled iron. Dr. 

 List states, in conclusion, that it is impossible to prove analytically 

 the assertion of M. Lohage, that pig-iron for puddling must con- 

 tain at least 9 per cent, of silicium. 



SOLDERING IRON AND STEEL. 



M. Bernard Lietar, of Rue de Houblon, Brussels, has just 

 patented an improved composition to be employed in welding or 

 soldering iron or steel. This composition consists of 1,000 parts 

 of filings of iron or steel, according to whether the composition is 

 intended to weld or solder iron or steel ; 500 parts of borate of 

 soda (borax) ; 50 parts of balsam of copaiba, or a resinous oil ; 



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