2 BULLETIN 1375, U. S. DEPARTMENT OF AGRICULTURE 
Electrically-heated moisture testers have lately come into general 
use. Their operation and efficiency have been studied and compari- 
sons drawn between them and the standard gas-heated machines. 
Wiring specifications have been worked out for electrically-heated 
machines and piping specifications for gas-heated machines. 
Both the construction of the apparatus and the methods of mak- 
ing the tests have been made as simple as practicable, so that reliable 
tests can be made by any careful worker, even though he has not had 
the benefit of special chemical-laboratory training. 
In making the tests it is of the utmost importance that the operator 
be a careful and honest worker, who can be depended upon to follow 
the instructions given for making the tests and who will report re- 
sults correctly. 
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Fig. 1. — Brown-Duvel moisture tester equipped with gas burners and gas-pressure 
regulator 
The instructions for making moisture tests given in this bulletin 
are applicable only when used in connection with the moisture tester 
herein described, specified, and illustrated, and do not apply to modi- 
fied forms of moisture testers. 
This apparatus was originally described by J. W. T. Duvel and 
E. Brown in 1907 in Bureau of Plant Industry Bulletin 99, "A 
Quick Method for the Determination of Moisture in Grain." Later 
this publication was reissued as Bureau of Plant Industry Circular 
72, under the title, "A Moisture Tester for Grain and Other Sub- 
stances and How to Use It." 
With the use of a Brown-Duvel moisture tester a single moisture 
determination on grain can be made in 25 or 30 minutes, and with 
a 6-compartment tester six tests can be made in approximately the 
same time as for a single test. In commercial work, where a large 
number of tests are to be made, one man and a helper, with the use 
