COPPER SULPHATE (BLUE VITEIOL). 



217 



Krystallazurin. — Ammoniacal copper sulphate (70 per cent of blue 

 vitriol). 



Kuiyferpreparat Gmund. — Emulsion of ammoniacal sulphate of 

 copper "(blue vitriol 20 per cent) in water, and 11 per cent of oil. 



Kupfer soda, etc., etc. 



Use against Smut {Ustilaginece). — It follows from the mode of 

 propagation of rust diseases that only the disinfection of the corn-seed 

 .and the dung can prevent the cryptogamic diseases of grain crops; 

 that no spraying can lessen, contend with, or prevent. Amongst 

 chemicals used to disinfect seed-corn blue vitriol is one of the most 

 powerful and the one in current vise. The only drawback lies in the very 

 ■decided sensitiveness of the grain to solutions of this poison. Different 

 [chemical] agents have not the same effect on the germination of 

 the seed. Chlorine water and lime water exert no injurious action ; 

 mineral acids retard germination without lessening the germinative 

 ■capacity, whilst metallic salts, such as green vitriol, blue vitriol, sugar of 

 lead, and others, are poisonous in small doses ; a germination of 100 per 

 cent is only obtained by observing certain limits of concentration, special 

 to each salt. In disinfection with blue vitriol a 0-5 per cent solution must 

 not be exceeded. More concentrated solutions yield the following : — 



TABLE XXVIl.—Showinrj the Effect of Steejnng Seed-Corn in Solutions of 

 Blue Vitriol of Different Stretigths for Different Periods of Time. 



The strength of the solution of blue vitriol and the duration of the 

 steeping ought to be such that the blue vitriol cannot enter into the 

 interior of the grain, but is confined to the disinfection of its exterior 

 surface. As soon as the poisonous salt penetrates into the seed 

 symptoms of poisoning are to be seen in the future plant. With solu- 

 tions of different strength the following result was obtained : — 



TABLE XXYIII.—Shoivlng the Effect on Height of Plant of Steeping Seed-Corn 

 in Sohitions of Blue Vtt7-ioi of Various Strengths. 



