Spraying Apple Orchards in a Wet Season. 389 



phate of lime and the basic sulphate of copper; these precipitates 

 do not again enter into solution. The presence of a particular com- 

 pound which keeps a part of the copper in solution is thus proved. 



"The following preparation was made in order to determine 

 the compounds which are formed in the mixture: Qne hundred 

 and sixty-six c. c. lime water freshly made and quickly filtered; 

 to this was added enough distilled water to make half a litre; one 

 gram of copper sulphate was dissolved in 100 c. c. of water and! 

 this was added quicldy to the dilute lime water whereupon the 

 mixture was immediately poured into a flask and hei-meticaHy 

 sealed. Thus I had 600 c. c. of liquid, a quantity more than suffix 

 cient to hold in solution all the sulphate of lime which should 

 form in the double decomposition. Five hundred c. c. of the 

 above mixture were filtered and analyzed. The table shows the 

 results obtained: 



" Composition of the mixture (a). — S02 0.32148 grams sulphuric 

 acid in one gram of the crystals of copper sulphate. 



" Found in the solution after completion of reactions (b), 0.2539. 



" Difference between a and b, 0.0675. 



" Per cent of the difference, 21.0. 



"Composition of the mixture (a). — CaO. 0.2372 grains lime 

 contained in the 166 c. c. of lime water used. 



" Found in the solution after completion of reactions (b), 0.2272. 



" Difference between a and b, 0.0456. 



" Per cent of the difference, 16.74. 



" Composition of the mixture (a). — CuO. 0.3186 grams oxide of 

 copper in the copper sulphate. 



" Found in the solution after completion of reactions (b), 0.0006. 



" Difference between a and b, 0,3180. 



" Per cent of the difference, 99.84. 



"From this analysis, it will be seen that the amount of S03 

 (0.0675) combined in the precipitate is much larger than that 

 corresponding to the basic sulphate of copper, which could not 

 exceed 0.023 grams. This proves tha* a large part of the sul- 

 phuric acid combined with the lime, and that the quantity of 

 liquid was sufficient to dissolve aU the sulphate of calcium formed. 



