43 



is compressed by means of a stationary engine and air pump. Ex- 

 cellent work may be done with such a machine. The relative ex- 

 pense of this as compared with other forms of power has not, so far 



Fig. 2t). — A carbonic-acid-gas sprayer. 



as we know, been accurately determined. It is, however, preferred 

 by some growers. 



Fig. 27. — A compressed-air sprayer in operation. 



Gasoline. — Steam engines are sometimes used, but they are usu- 

 ally found too bulky and heavy for vineyard work. Alcohol has not 

 yet apparently been used in this connection. A cheap denatured 



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