UNITED STATES DEPARTMENT OF AGRICULTURE 
DEPARTMENT BULLETIN No. 1375 
Washington, D. C. 
Issued February 1926 
Slightly revised February 1936 
THE BROWN-DUVEL 1 MOISTURE TESTER AND HOW TO OPERATE IT 
By D. A. Coleman 2 and E. G. Boerner, Grain Investigations, Grain Division, 
Bureau of Agricultural Economics 
CONTENTS 
Page 
3 
4 
Description of the apparatus 
Construction specifications 
Description of accessories o 
Supply pipes for gas-heated moisture 
testers 15 
How to make a moisture test 17 
How to test diSferent substances 18 
Standardizing the moisture tester 20 
Variations in heating time caused by 
variations in gas pressure 23 
Variations in heating time and mois- 
ture-test result caused by position 
and condition of wire gauze 28 
Variations in heating time caused by 
variations in thermometer bulb im- 
mersion 29 
Page 
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 1 39 
Drawing and handling samples 41 
Special points for consideration 42 
The official grain standards of the United States specify the 
water-oven method as the basic official method for determining the 
moisture content of corn and the air-oven method for all other 
grains. The standards permit, however, the use of any device and 
method which give results equivalent to those obtained by the official 
methods. When the Brown-Duvel device is used for the purposes 
of grain inspection, the operative instructions contained in this bul- 
letin are essential for its efficient use. 
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. 848G1G 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. 
41523°— 3( 
