Half the quantities should be used on non-dormant 

 wood. Special contrivances are made to drop the cyanide 

 into the acid and water from outside the shed or box, so 

 that any chance of danger from the fumes, which are 

 deadly poisonous, are obviated. The cyanide should be 

 at 98 per cent, strength, and the sulphuric at about 184 

 specific gravity. Sodium cyanide does as well and is 

 cheaper than potassium cyanide. 



