TUBER CROP PROJECTS 



215 



barrels beside the water supply. No location is better than right on 

 the bank of a running stream or pond. Weigh 50 pounds of cop- 

 per sulphate in a burlap sack and fasten as near to the top of one 

 of the barrels as possible. This is accomplished easily by pulling 

 the top of the sack over the edge of the barrel and nailing. Then 





Fig. 57. — Potatoes: Middle lot, unsprayed (same areas in each case); to the 

 left, sprayed (71 bushels per acre) ; to the right, low pressure sprinkling (30 

 bushels' increase per acre). 



fill the barrel with water. The above operation should be done a 

 few hours at least before the spraying begins, so that the copper 

 sulphate may have time to dissolve. Do not put the copper sul- 

 phate into the bottom of the barrel and expect it to dissolve. 

 Dump 50 pounds of stone lime into the other barrel, and add water, 

 slowly at first, sprinkling evenly over the lime, and as the chunks 

 begin to dry, add a little more until a vigorous heat begins to 

 generate. Then add the water rapidly enough to prevent the 

 formation of dust, but slowly enough to keep it the consistency 

 of thick mud. Let it cook until when stirred from one side to the 

 other it is as smooth as butter and of about the same consistency. 



