79 



ing it in diluted surfuric acid. Potassium Cyanide requires for each 

 ounce, one fluid ounce of acid diluted with three fluid ounces of 

 water. Sodium Cyanide for each ounce requires l l / 2 fluid ounces 

 of acid diluted with 2 fluid ounces of water, but as ^4 of an ounce 

 of the sodium is as strong as an ounce of the potassium, and it is 

 a little cheaper per ounce, a saving is made in using it. This 

 refers to the best grade of each chemical and it is important to 



Method of Marking Tent. 



use the best. With cyanide of potassium the best is known as 

 99% ; with cyanide of sodium it is called 129%, and the sulphuric 

 acid is known as 93%. 



These chemicals obtained from the general drug trade are not 

 always sufficiently pure, and the Horticultural Commissioner's office 

 will always be able to inform anyone how to get pure chemicals. 

 We can also furnish the tables or schedules of dosage which will 

 be correct. 



