102 NEW YORK ZOOLOGICAL SOCIETY. 



entering the leads of hose, of which any reasonable number may 

 be attached, the spraying mixture runs through a fine brass sieve, 

 which removes all insoluble matter which might clog the nozzles. 

 By the turn of a valve stem this sieve may instantly be cleaned 

 of all matter deposited thereon. 



From the fact that there is no heavy engine to be transported 

 from place to place, and from the absolute simplicity of this outfit, 

 which has but few working parts, and practically nothing to get 

 out of order, many trees in a dense forest, otherwise inaccessible, 

 can be reached. 



By some simple experiments it was found that a very strong 

 solution of copper sulphate could be used without injury to the 

 foliage. It was therefore determined to use what is commonly 

 called " potato strength," or 4 pounds of copper sulphate to 10 

 gallons of water. The acidity or non-acidity of the mixture was 

 always determined by the simple ferrocyanide of potash test. A 

 stock solution of this was always kept on hand, so that no time 

 would be lost in recharging the tank on the spraying machine. 



It was found that on an average a 150-gallon tank would 

 spray three large trees. Later on, however, as the men became 

 more proficient in handling the nozzles, this number was in- 

 creased. On account of the size of the trees only two leads of 

 hose were used. It was found necessary to have but two men 

 to do the spraying, one to go to the highest portion of the tree 

 and one to work upon the lower portion, either from the tower of 

 the outfit or from short ladders. The driver helped in moving 

 the ladders, agitated the mixture, and regulated the gas pressure 

 in the tank. With this number of men it was possible to spray 

 an average of four trees per day. 



The spraying of very large forest trees is of course vastly more 

 expensive and is a slower and more dangerous task than spray- 

 ing ordinary orchard trees, which in nearly all cases could be 

 reached from the ground or from the tower platform. One great 

 advantage of the Bordeaux Mixture over the copper sulphate so- 

 lution is that in spraying large trees whereon a limb may be easily 

 overlooked, its pale blue color shows exactly what part has been 

 sprayed. 



It was impossible to go over our trees more than once during 

 the past season. Just how far we have checked the progress of 

 the disease is a matter of conjecture until the growing season 

 reveals the facts. Considering, however, the ease with which 

 the spores may be transferred by the action of the wind or by 

 squirrels, birds, and insects from an affected tree to another 



