B. P. I.— C15. 



A MOISTURE TESTER FOR GRAIX AND OTHER 

 SUBSTANCES AND HOW TO USE YL' 



INTRODUCTION. 



The apparatus described in this circular, which is known com- 

 mercially as the Brown-Duvel moisture tester, was originalh' des- 

 cribed in 1907 in Bulletin 99 of the Bureau of Plant Industry, 

 entitled ''A Quick Method for the Determination of Moisture in 

 Grain," and was developed primarily to meet the demands of grain 

 dealers for a rapid and exact method of determining the moisture 

 content of commercial corn. Since that time some slight modifica- 

 tions have been made in both the apparatus and the method, and 

 specific instructions have been worked out for making moisture tests 

 of the more important cereal grains and some of the more important 

 seeds. It has been demonstrated that the method is entirely practi- 

 cable for making moisture determinations of practically all sub- 

 stances which admit of a free circulation of the oil during the heating. 



Both the construction and the process have been made as simple 

 as possible, so that reliable tests can be made by any careful worker, 

 even though he has not had the benefit of special training in a chemi- 

 cal la])oratory. It is, liowever, of the utmost importance that the 

 operator be a careful and honest worker who can be depended upon 

 to follow simple instructions and to report results correctly. It 

 must be })orne in mind that the instructions given in this circular 

 are applicable only when used in connection with the moisture tester 

 herein described and illustrated and do not apply to modified forms 

 of testers. 



a This circular has been prepared in order to provide specific instructions for making 

 moisture determinations of different substances and to bring about more uniformity 

 in the use of the apparatus. The use of this moisture tester with corn has resulted 

 in more attention being paid to the proportion of dry matter contained therein, and 

 already considerable quantities of corn are being sold on a percentage statement of 

 moisture or on grades in which the percentage of moisture is limited, and it is believed 

 that the time is not far distant when this will be the universal practice. The apparatus 

 described was developed by Mr. Edgar Brown and Dr. J. W. T. Duvel, of this Bureau, 

 and has been patented by them in order to secure its free use by the people of the 

 United States. — Wm. A. Taylor, Acting Chief of Bureau. 



61825°— Cir. 72—10 3 



