INDUSTRIAL PROGRESS DURING THE YEAR 1873. xliii 



potash salts, which, taken up by the sheep from the soil, are 

 excreted with their sweat, and remain attached to the fleece. 

 This suint, which Avas formerly wasted, has for some time 

 been utilized as a source of potash compounds, and is now 

 found to be a most available material for the manufacture of 

 potassium ferrocyanide. In the production of the caustic al- 

 kalies a little improvement is suggested by Pollacci. Some 

 years ago Wohler ^^roposed to obtain these substances by 

 igniting the nitrates with metallic copper, and treating the 

 product with water ; but, unfortunately, the alkalies thus pre- 

 pared were always contaminated with some oxide of copper. 

 Pollacci substitutes iron filings for copper in this process, and 

 claims to obtain the caustic soda and potash quite pure. The 

 refuse of wool, horn, feathers, leather, skins, sponge, etc., ma- 

 terial rich in nitrogen, but hitherto of little or no use except 

 for fertilizing, has at last been utilized by L'Hote. He mixes 

 the material first with a solution of caustic soda in ten parts 

 of water, and allows the mass to digest until it has acquired 

 a pasty consistence. He then adds quicklime and distills, be- 

 ginning at a low temperature, and increasing to a red heat. 

 The vapors, rich in ammonia, are passed into common sul- 

 phuric acid, and ammonium sulphate, a substance of great 

 commercial value, is thus obtained. The residuum in the re- 

 tort consists mainly of sodium carbonate and lime, which, by 

 treatment with water, may be made to give back the caustic 

 soda used at the beginning of the operation. 



Some interesting facts concerning Metallurcjif have been 

 made public. Percy, for instance, has shown that manganese 

 may be used instead of nickel in the manufacture of German 

 silver, the product being quite undistinguishable from the al- 

 loy in general use. Bajault and Roche have described a new 

 process for the manufacture of steel. A mixture of pulverized 

 iron ore and molten pig-iron is cast in metallic moulds, which 

 form a part of the final ingots. These ingots are then heated 

 to redness in a peculiar furnace for a considerable time, car- 

 bonic oxide is given ofi", and crude steel is formed. This crude 

 steel can then be cast in the ordinary way. By this process 

 any degree of carbonation can be produced in the steel, the 

 proportions of cast iron and ore being readily fixed before- 

 hand. 



One more striking contribution to chemical technology 



