1905.] Adulteration of Sulphate of Copper. 543 



many other fungoid attacks, is well known, whilst solutions of 

 this substance in water at varying strengths are used for the 

 prevention of bunt and smut on cereals (Leaflet No. 92), for 

 the destruction of charlock (Leaflet No. 63), and for the cure 

 of foot-rot in sheep (Leaflet No. 154). 



In purchasing sulphate of copper care should be taken to 

 demand a product of 98 per cent, purity, material offered as 

 " agricultural " sulphate of copper being avoided. 



The usual adulterant of sulphate of copper is sulphate of 

 iron, which is much cheaper. An easy test for the presence of 

 iron in the sulphate of copper is to dissolve a little in water and 

 add ammonia with constant stirring until a deep blue liquid 

 forms ; any quantity of brown flocks floating about in this 

 blue liquid indicates the presence of so much iron that the 

 material should be subjected to a proper analysis previous to 

 rejection. 



A case has recently been brought under the notice of the 

 Board in which sulphate of copper purchased for the pre- 

 vention of "smut" proved on analysis at the Government 

 Laboratory to have the following composition : — - 



Per cent, 



Crystallised Sulphate of Copper (" blue vitriol ") ... 17 "6 



,, Iron (" green vitriol ") ... ... 82*4 



1000 



This grossly adulterated substance was sold as " blue vitriol," 

 and, needless to say, was practically useless for the purpose for 

 which it was intended. The suspicions of the farmer by whom 

 it was bought were aroused by the fact that wheat dressed 

 with it was spoilt by smutty ears. The presence of iron 

 sulphate in anything like as large a quantity as above indicated 

 makes the mixture much lighter in colour than good " blue 

 vitriol." 



The Board would direct the attention of farmers to the im- 

 portance of requiring a guarantee from the seller that the 

 material supplied has a purity of 98 per cent. As a further 

 safeguard the simple test suggested above should be made, as 

 the use of an adulterated article can only result in a considerable 

 loss. 



