1 GENERAL SUMMARY OF SCIENTIFIC AND 



its preparation, its properties, and those of many of its com- 

 pounds. Heumann proposes, for the preparation of pure 

 cuprous chloride, the action of hydrochloric acid upon an 

 intimate mixture of copper oxide and zinc-dust ; the acid to 

 be poured when saturated into previously boiled water. The 

 cuprous chloride separates as a snow-white crystalline pow- 

 der. 



Henri Morin has analyzed a series of Chinese and Jap- 

 anese bronzes sent to the Paris Exposition, and noted for the 

 beauty of their patina. He finds them remarkable chiefly for 

 containing lead, the first group having as high as twenty per 

 cent, even ; the second group contained zinc in addition. The 

 beauty of the patina hence results from the composition of 

 these alloys, and the author has been able to obtain the same 

 patina on imitation alloys made synthetically. Chandler 

 Roberts has given an account of the processes employed by 

 him to obtain accurate standard trial plates for verifying the 

 coinage at the British Mint, both gold and silver. Wolcott 

 Gibbs has published a most elaborate memoir upon the hexa- 

 tomic compounds of cobalt, in which he describes a new octa- 

 mine base, which he calls Croceocobalt, together with a num- 

 ber of new salts of this and the other cobalt bases. But the 

 point of greatest interest in the research is the discovery of a 

 series of metameric bodies among these cobaltamines the first 

 observation of true metamerism in inorganic chemistry. This 

 summary would be incomplete without a mention of the re- 

 markable casting of a 250-kilogramme ingot of platinum- 

 iridium for the new standards of the International Metric 

 Commission ; of the extended research of Abel, of the En- 

 glish War Department, on explosives ; and of Berthelot on 

 refrigerating mixtures and their action. 



The department of Organic Chemistry not only has more 

 workers, but is at present a more extended field. Blochmann 

 has proposed to determine acetylene from the copper con- 

 tained in the acetylide, produced by passing the gaseous 

 mixture through ammoniacal cuprous chloride. In ten litres 

 of coal gas, for example, he found from 0.063 to 0.064 per cent, 

 of acetylene. In the gases from a Bunsen burner, burning at 

 the base of the tube, he found twelve times this quantity. 

 P. and A. Thenard have exhibited to the French Academy a 

 tube containing acetylene solidified by the silent electric dis- 



