Smithsonian Report, 1944.—Porter PLATE 6 
1. MODERN TYPE OF PORTABLE POWER SPRAYER. 
Because of wartime manpower shortage, the tractor driver is also applying spray to the lower parts of the 
tree by the use of a flexible broom type of nozzle arrangement. Ordinarily the spraying of the lower parts 
of the tree would be done by a man on the ground, who would apply the material from a number of direc- 
tions. (Photograph taken in 1944 by L. F. Steiner.) 
2. AIR-BLAST TYPE OF SPRAYER. 
The liquid is pumped at low pressure into an air blast produced by an airplane propeller. This outfit 
permits the application of the spray in a very speedy manner and with minimum use of manpower. 
(Photograph by L. F. Steiner.) 
