504 



tent, is found convenient for covering and uncovering trees, and for 

 keeping the tent stretched out. At the base of the tent, and below 

 the ring, a gas-tight flange or canvas collar, about a foot wide, is 

 provided, and rests on the ground. After the tent has been charged, 

 this canvas collar is slightly banked up all round with earth, to 

 prevent the gas escaping. 



Before fumigating, inspect the tents. No hole, however small, 

 should be allowed to go unpatched. 



Trees too large to be covered with a tent may be fumigated 

 under a large gas-tight canvas sheet. 



Also provide yourself with : 



1st. A common earthenware basin, 6 to 9 inches wide, accord- 

 ing to size of tent or tree. 2nd. Scales for weighing 

 the cyanide of potassium. 3rd. A graduated glass for 

 measuring the fluid ounces of sulphuric acid and of 

 water. 4th. If a gas-piping ring is not provided to 

 keep the tent spread out at the base, have an 18ft. 

 light pole, with rope and pulley, to hoist the larger 

 tents over the tree. 5th. Sufficient number of loz. 

 packets of cyanide of potassium, 98 per cent, purity, 

 which must be kept in an air-tight jar. 6th. Sulphuric 

 acid in a bottle with a glass stopper. 7th. Water. 



HOW TO BECKON CUBIC CAPACITY. 



Consider the covered tree as a cylinder. To calculate its 

 contents, multiply half the width by itself, then by the height; 

 then multiply by 3, or, to be more accurate, by 3f . Thus a tree 

 eight feet wide by eight high would be 4x4x8x3 = 384 cubic 

 feet, or say 400 cubic feet. Cyanide of potassium, HOZ. per 100 

 cubic feet, would be 6ozs., half as much again, or 9ozs. of sulphuric 

 acid, with half as much again of water as acid, or 13^ozs., making 

 a total of 28Jozs., or 7ozs. of the combined chemicals for every 

 100 cubic feet. 



DOSES AND TIME. 



Cyanide of potassium, 98 per cent, purity, loz. per 100 cubic 

 feet. 



Sulphuric acid of commerce, 1| fluid oz. per 100 cubic feet. 

 Water, 2| fluid oz. per 100 cubic feet. 



NOTE. If fumigating in the winter for the more resistant 

 scales, and particularly San Jose scale, the doses might be increased 

 to : Cyanide of potassium, 1| oz.; sulphuric acid, 2^ fluid oz.; and 

 water, 3| fluid oz. per 100 cubic feet. 



