THE POTATO 185 



« 



of sacking to remove grit; it should then be further 

 diluted with water to about ten gallons and poured 

 slowly into the cask containing the solution of 

 copper sulphate. As the two fluids mix they must 

 be thoroughly stirred. If the lime has been slaked 

 slowly and the whole process has been carried out 

 as indicated, a gelatinous precipitate forms in the 

 cask — that is, the water becomes filled with 

 starch-like flecks; these remain in suspension for a 

 long time. On the other hand, if too little water 

 has been employed, or if the lime has not been 

 properly prepared, or if stirring has been neglected, 

 a comparatively coarse powder forms in the mix- 

 ture and soon settles, so that after standing for an 

 hour or two the fluid in the upper part of the cask 

 is quite clear. The starch-like precipitate, when 

 once it dries on foliage, adheres closely for months, 

 whereas the coarser powder, which results from 

 careless preparation, washes off readily, so that the 

 leaves lose much of their protection after the first 

 heavy rain, and spraying does little or nothing to 

 check disease. 



"When Bordeaux mixture has been made it 

 should be diluted if necessary and used without 

 delay. One or two days' supply only should be 

 made at a time, for although well-made Bordeaux 

 mixture will keep fairly well for several days, it is 

 best used within forty-eight hours. 



"For spraying potatoes under favorable con- 

 ditions the mixture, if made in a concentrated 

 form, should be diluted to 100 gallons, but when 

 spraying must be done in damp weather it should 

 be diluted to from seventy-five to ninety gallons. 

 Before pouring into the sprayer it should be stirred 

 thoroughly. If possible, a sprayer provided with 

 a dasher or other contrivance for keeping the mix- 



