390 Agricultural Experiment Station, Ithaca, N. Y. 



"The precipitate was washed and treated on the filter with a 

 concentrated solution of the chloride of ammoma. This reagent 

 has the power of completely dissolving the basic sulphate of copper 

 compounds even if they are found combined with the sulphate 

 of lime in the form of a double salt. It does not act upon the 

 hydra/be. Such a reagent, which to my knowledge has never been 

 applied in similar cases, allows of the complete separation of 

 those two classes of copper compounds which are produced when- 

 ever an alkaline hydrate acts upon a solution of a salt of coppm*. 

 Analysis showed: 



Grams. 



SO3 . 0528 



GuO 0.0G7G 



CaO 0.0200 



"Calculating from the above data, it will be seen that 21.21 per 

 cent of the copper in the precipitate is in the form of a basic 

 sulphate, while 78.78 per cent occurs as a hydi'ate. It must, 

 however, be remarked that lq this copper mixtm^e as prepared by 

 Cavazza, 600 grams sulphate of copper and a hectoliti*e of lime 

 water, the propoi'tions are found to vary, though only within 

 narrow limits: 



"From the above experiments the following conclusions may 

 be drawn: 



" 1. In the Bordeaux mixture prepared with quick lime .a smalj 

 quantity of copper always remains in solution. This amount often 

 escapes notice, but it may be deteimined with the aid of electricity. 

 The quantity of lime used affects the amount of copper in solution 

 and when an excess of lime is used only small traces of copper 

 can be recovered. 



"2. The quantity of copper which can remain in solution is 

 considerably larger when slaked, or somewhat carbonated lime 

 is used, and when it is added dh'ectly into the solution of the 

 sujlphate of copper. When iusufiiciently slaked lime is used 

 the amount of copper which can remain in solution is some- 

 times considerable, although the liquid is decide<lly aUcaline. 



"3. The copper is precipitated in the Bordeaux mixture in 

 ihe form of the hydrate, basic sulphate, and the double basic 



