UNITED STATES DEPARTMENT OF AGRICULTURE 
DEPARTMENT BULLETIN No. 1375 
Washington, D. C. 
February, 1926 
THE BROWN-DUVEL 1 MOISTURE TESTER AND HOW TO OPERATE IT 
By D. A. Coleman 2 awl E. G. Boerner, Grain Investigations, Grain Division, 
Bureau of Agricultural Economics 
CONTENTS 
Page 
Description of the apparatus 3 
Construction specifications 4 
Description of accessories 5 
Supply pipes for gas-heated moisture 
testers; 15 
How to make a moisture test 17 
How to test different substances 18 
Standardizing the moisture tester 20 
Variations in heating time caused hy 
variations in gas pressure 23 
Variations in heating time and mois- 
ture-test result caused hy position 
and condition of wire gauze 28 
Variations in heating time caused by 
variations in thermometer bulb im- 
mersion . 29 
Tage 
Influence of cooling time on moisture- 
test results 30 
Priming tests 31 
Volume of oil v. moisture-test result- 33 
Brown-Duvel moisture testers equipped 
with electric heaters 33 
Tests with alcohol and gasoline 
burners _ _ 39 
How to choose extinguishing tempera- 
tures 39 
Drawing and handling samples 41 
Special points for consideration 42 
The Brown-Duvel moisture tester, as it is commercially known, 
and its method of testing moisture in grain were developed primarily 
to meet the demands of the grain trade for a rapid method of deter- 
mining the moisture content of the various grains, and is specified by 
the United States Department of Agriculture as the official method 
for determining the moisture content of the grains for which official 
standards have been established under the provisions of the United 
States grain standards act. 
Since the method was first developed, it has been further perfected 
for determining the moisture content of rice, of the more important 
seeds, of flour and meal, and certain other commodities. Modifications 
have been made both in the apparatus and in the methods for making 
tests and more specific instructions have been recently developed 
for so making the moisture tests as to accomplish greater accuracy 
and uniformity in the results with the apparatus. 
1 This apparatus was originally invented by J. W. T. Duvel and Edgar Brown, United 
States Department of Agriculture, who hold Public Service Patent No. 848616 on the 
apparatus. 
2 Credit is given. John H. Cox and H. C. Fellows, Grain Division, Bureau of Agricul- 
tural Economics, and to H. B. Musser, formerly scientific assistant in Grain Standardi- 
zation, Bureau of Agricultural Economics, for some of the experimental data contained 
in this bulletin. 
60637 c 
