ae BULLETIN 379, U. S. DEPARTMENT OF AGRICULTURE. 
vibration due to the threshing. In no case has it released itself 
prematurely. | 
It has been suggested that, when not in use on the separator, this” 
device can be mounted on running gears and used for general fire 
protection about the farm. | 
A special nozzle was designed for use with this extinguisher. It 
is shown in detail in figures 2, Plate XI. 
Large-scale drawings of these three devices are on file in the 
Office of Public Roads and Rural Engineering, and may be secured 
on application by manufacturers, owners, or operators of threshing 
outfits who seriously contemplate the installation of one or more of 
‘them. 
SPECIAL ACKNOWLEDGMENTS. 
In connection with carrying on the work described in this bulletin, 
special acknowledgment is due to Dr. H. H. Brown, assistant chem- 
ist, Bureau of Chemistry, and Elmer Johnson, assistant mechanical 
engineer, Office of Public Roads and Rural Engineering, for assist- 
ance rendered in conducting experiments in the laboratory to deter- 
mine the inflammability of smut dust, in designing the apparatus 
described herein, and in conducting tests at the Bureau of Mines’ 
galleries at Pittsburgh, Pa., and with grain separators at Arlington 
Experimental Farm. 
Acknowledgment is also due to the Grain Standardization Labora- 
tory, Portland, Oreg., for assistance in investigations and in gollec- 
tion of grain samples; to the Bureau of Plant Industry for assist- 
ance in experimental work at the Arlington Farm; and to the Bureau 
of Mines for use of the explosion galleries and laboratories at 
Pittsburgh, Pa. 
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