388 Agricultural Experiment Station, Ithaca, N. Y. 



slaked for about one-half hour oiilj. Liquid filtered after one 

 hour. 



" Metallic copper per litre of the solution, 0.1022. 



" Sulphate of copper crystals per litre, 0.4007. 



''Remarks. — The filtered liquid alkaline and greenish. 



'Preparation of mixture. — Sulphate of copper, twenty grams; 

 caustic lime as above, ten grams. The lime was pulverized and 

 added directly, little by little, to the copper sulphate solution. 

 Liquid filtered after one hour. 



" Metallic copper per litre of the solution, 0.147. 



" Sulphate of copper crystals per litre, 0.5725. 



"Remai-ks. — Filtered liquid alkaline and greenish. 



"Preparation of mixture. — Sulphate of copper, twenty gi'ams; 

 caustic lime, ten grams. The lime was added immediately after 

 having been calcined in a platinum foil over a spirit lamp. 

 Liquid filtered after one hour. 



" Metallic copper per litre of the solution, 0.2345. 



" Sulphate of copper crystals per litre, 0.9192. 



"Remarks. — The temperature of the liquid after adding the 

 lime did not rise more than three degrees C. TRe filtered liquid 

 was alkaline and greenish. In the course of twelve hours 

 crystals, etc., were deposited. 



" The quantity of copper remaining in solution diminishes 

 rapidly as the liquid is allowed to stand. The liquids which con- 

 tained the larger amounts of copper formed at the end of six, 

 twelve and twenty-four houi*s a greenish white deposit sometimes 

 mixed with bluish-green crystals. The following amounts of 

 metallic copper were detenuined in a filtered solution: 



"After one hour, 0.1012 grams; after twelve hours, 0.0452 

 grams; after twenty -four hours, 0.005 grams. 



" Similar results were also obtained when the mixture was made 

 on a large scale. 



" The action of heat is favorable to the decomposition of the 

 copper comi)ounds remaining in solution. When these are so 

 abundant that the liquid has a greenish color, the application of 

 heat will immediately cause a copious precipitation of the sul- 



