394 
Journal of Agricultural Research 
Vol. VII, No. 9 
sprays can be increased to a considerable degree by the addition of soap, 
but when more than 4 pounds of soap are used to 50 gallons of i-to-630 
nicotine-sulphate solution the effectiveness of these solutions decreases; 
Fig. i.—E fficiency and wetting power graphs for sprays in group i, containing io ounces of nicotine sul¬ 
phate and varying quantities of soap, and group 4, containing various amounts of soap with no nicotine. 
Wetting values are given in the column at the right. 
(3) that if soap is used without the nicotine, 6 pounds to 50 gallons of 
water is all that can be used economically, since more concentrated 
solutions do not have an appreciably greater efficiency; (4) that when 
