INDUSTRIAL PROGRESS DURING THE YEAR 1874. lxiii 



iron scrap, sponge, etc., with the manganese mineral. The 

 ferro-manganese thus made contains 65 per cent, of manga- 

 nese, and costs 2^ to 3 francs the kilogramme. But as only 

 2 per cent, of it is necessary in the bath, it can not be con- 

 sidered costly. 



Fremy has published an elaborate report on cannon metal, 

 in which he has given in extenso his own views upon cop- 

 per-bronze alloys. 



A considerable discussion has taken place on the question 

 of the true constitution of bleaching powder, Goepner assert- 

 ing the old view of Bertholet, that it is a compound of lime 

 and chlorine directly, and Schorlemmer and others that it 

 contains hypochlorite of calcium. Richters and Juncker, 

 from their experiments, assign to the bleaching compound 

 existing in commercial chloride of lime the formula CaOCl 2 , 

 but suppose that it is decomposed by water into CaCl 2 and 

 CaCl 2 2 . Some of this latter product is always present in 

 the commercial article, produced by the presence of moisture 

 in the manufacture. 



Bischof, of Glasgow, has introduced iron -sponge, in the 

 state in which it is obtained by reduction from the ore with- 

 out fusion, for chemically purifying water. The results thus 

 far seem very satisfactory, the iron not only removing or- 

 ganic impurities, but also every trace of lead. 



Melsens has succeeded in producing an excellent artificial 

 bone-black for decolorizing purposes, by incorporating with 

 wood-charcoal a solution of bone-ash in hydrochloric acid 

 and subsequent ignition. 



Hell and Medinger have been successful in isolating an acid 

 of the composition C n H 20 O 2 from crude Wallachian petro- 

 leum. 



Helbing has detected in the most volatile portions of coal- 

 tar distillates three members of the olefine series of hydro- 

 carbons. Amylene exists there in largest quantity, crotony- 

 lene next, and hexylene least. 



Fontenay has analyzed a blue pigment used by the Egyp- 

 tians fifteen centuries before the Christian era, and called bv 

 them lapis imite, and by Theophrastus Egyptian blue. It 

 is essentially a copper silicate, containing some lime, alumi- 

 na, and soda. It was successfully imitated by heating slow- 

 ly to a high temperature a mixture of 70 parts of white 



