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27 
have been used with good results in the work of the Gypsy Moth 
Commission, both for street trees and in the public parks. A steam 
apparatus, however, of such a capacity that a pressure of 75 pounds 
per square inch may be gained will enable the operation of four or 
five lines of hose simultaneously. The rapidity of work will therefore 
be doubled, and certainly by the use of two such pumps the shade trees 
of any ordinary city can be gone over with sufficient rapidity to destroy 
all insects within the required time. A boiler mounted on a truck, the 
boiler to be complete with all fixtures, smokestack, bonnet, firing tools, 
springs to the truck, and a pump having a capacity of 10 to 20 gallons 
a minute connected with the boiler ready for operation, can be pur- 
chased for a sum well within $500. This truck should be mounted on 
wheels with broad tires, for running over sandy roads. Connecting 

Fig. 11.—Fall webworm. Suspended larva and section of web—natural size (original). 
this apparatus with a proper tank cart would be an additional expense, 
not to exceed $100 for a tank of a capacity of 200 gallons. Such an 
apparatus, furnished with hose and smoothbore nozzles of about one- 
sixteenth inch in diameter, when discharging under 40 pounds pres- 
sure from each of several such nozzles, would spray about half a gal- 
lon of insecticide mixture per nozzle per minute. 
A strong steam pump, to be used in connection with a small oil- 
burning boiler, the whole apparatus on a smaller scale than that 
described above, has been estimated at $275 by a prominent New York 
firm, delivered on board the cars. 
There is no reason why an old steam fire engine could not be 
readily arranged for this shade-tree spraying work. In one or two 
instances a steam fire engine has been used for this purpose without 
