INSECTICIDES, PREVENTIVES, AND MACHINERY. 457 



more desirable when lime or similar thick washes are to be 

 applied. 



As to tanks, anything that holds water will serve ; and the 

 farmer should so arrange matters as to make the best use of what 

 outfit he already has. Nothing will be gained by describing the 

 various arrangements for reaching the tops of trees or all sides of 

 a row of any field crop. These are details that must be worked 

 out by the individual with the aid of the catalogues which manu- 

 facturers will be glad to send on request. 



Gasoline and steam engines are used to produce power where 

 large orchards of large trees must be sprayed, and in cities 

 where shade trees are to be dealt with, such machines are usually 

 built for specific needs. A recent type is a machine in which the 

 axles are geared to an air-pump and the power is furnished by the 

 air so compressed. 



The simplest type of power machine is a steel tank from which 

 the mixture is forced by the pressure of liquid carbonic acid 

 gas. This machine has the power under the most absolute con- 

 trol, and requires no exertion to produce it. 



A good machine for applying an insecticide must distribute it 

 quickly, thoroughly, and economically ; and whatever the outfit 

 may be, it must be adapted to do its best work under the condi- 

 tions of the locality where it is to be used. 



Brief mention may be made of the atomizers and compressed 

 air sprayers of small capacity for garden use, which may be 

 purchased of almost any seedsman or hardware dealer, so that 

 not even the city gardener need be without his spraying outfit. 



Applications in dry form are gaining in favor in localities 

 where the water supply is limited ; and in place of the old- 

 fashioned hand bellows there are now fan-blowers of all sizes — 

 dusters that will cover half a dozen rows of potatoes or a large 

 apple-tree with equal ease and thoroughness ! Simple methods 

 of distributing dry Paris green in cotton fields through a pair of 

 sacks are in local use ; but are not available to an equal extent 

 elsewhere. 



Combination or emulsion pumps, spraying oil and water in a defi- 

 nite percentage, have been on the market for some years, but have 

 not proved satisfactory in all respects. So long as they work 

 well the results obtained are good ; but the two pumps or suc- 

 tions do not always work evenly, and the least disturbance to one 



