Spraying Devices and Machinery. 207 



ferred. This is especially true when several different crops are 

 to be treated. 



If powders are preferred, the hand bellows will be found 

 very serviceable when only a small area is to be covered. For 

 more extensive work, machines with revolving fans to produce 

 stronger air blasts will answer the purpose better, since the 

 work can be done more easily and also more rapidly. 



V. MERITS OF THE VARIOUS SPRAYING DEVICES. 



The bulk of insecticides and fungicides are applied in liquid 

 form, and so much machinery for making the applications is 

 offered for sale that the selection of the best is by no means 

 an easy matter. The conditions under which the materials 

 are used are so exceedingly varied, that recommendations 

 which apply in one case have little value in another. Only 

 general statements can be made with safety, and each indi- 

 vidual must select that which in his judgment promises to be 

 most effective. Several of the ideas here advanced are not in 

 accord with those of some writers whose opinions are entitled 

 to very careful consideration ; but since they are the result 

 of personal experience and observation in the field, and of ex- 

 periment in the laboratory, the conclusions reached are given 

 with the belief that no one who follows them will go far 

 astray. The subject is the more difficult to treat from the fact 

 that personal bias often enters, and that which suits one man 

 may or may not suit another. The manufacturers' side must 

 also be considered, since it is but right that their products 

 should be justly valued. Unfortunately, it is impossible to 

 enter into the merits and defects of all spraying contrivances 

 offered for sale; the descriptions, therefore, will apply only to 

 the types of the more important groups.* 



A few points apply in the selection of any spraying machine. 

 As a rule, it is better to have all working parts of brass, the 

 body of the pump being either of brass or of iron. The alloy 

 is more durable than iron, since it is not so easily corroded by 

 the liquids used, nor by exposure to air. The first cost is 

 greater, but in the end the extra price is well spent. All brass, 

 however, is not suitable for spray pumps. Ammonia water has 



