DESCRIPTION OF METHOD. 



It has therefore become necessary to devise some suitable method 

 and apparatus for determining the amount of water in corn and other 

 grains before any hope of phicing the orading of orain on a i)i'r(ent- 

 ag-e basis can be entertained seriously at any of our large grain cen- 

 ters. It is hoped that the method described in the following pages, 

 Avhich is applicable to the testing of wheat and other grains as well 

 as corn, will be sufficiently rapid and easy to make it of practical 

 value to the grain trade, and possibly to other industries. 



DESCRIPTION OF A METHOD FOR THE RAPID DETERMINATION 



OF MOISTURE. 



TliB fundamental principle" on which this method of moisture 

 determination is based consists in heating whole urains in oil to a 

 temperature considerably above 

 that of boiling water and thus 

 drivino- out the water, which is 

 afterwards condensed and meas- 

 ured in a graduated flask. AVith 

 this method it is possible to deter- 

 mine the percentage of water in a 

 sample of corn in from twenty to 

 twenty-five minutes. 



One hundred cubic centimeters 

 of a good grade of hydrocarbon 

 oil are measured and poured into 



a glass distillation flask (see fig. fig. l.-Bahmce for weighing grain samples. 



10). One hundred grams of corn 



are Aveighed on a torsion balance similar to the one shown in figure 1, 

 the corn being emptied at once into the flask containing the oil. The 

 neck of the flask is closed with a good rubber stopper carrying a ther- 

 mometer, the bulb of which should extend well into the mixture of oil 

 and corn. The side of the flask is then connected with a condenser by 

 means of a second rubber stopper. AVith a strong gas burner the corn 

 in the oil bath is then heated until the thermometer registers 190° C. 

 (374° F.), at which time the flame is extinguished. The time 

 required for the temperature to reach 190° C. will be from ten to 

 fifteen minutes, depending on the amount of water in the corn and 

 on the volume of the flame. Eight or ten minutes after the flame has 



a This principle has ah-eacly been described by Dr. J. F. Hoffmann in Zeit- 

 sehrift fiir Angewandte Chemie, Berlin, 1902. p. 1193, and in the Grain Dealers' 

 Journal, Chicago. May, 19()r., p. .520. However, the apparatus used by Hoffmann 

 and likewise the details of the method described by him have proved unsuitable 

 where large numbers of samples are to be analyzed. Consequently, in August, 

 1905. experiments were begun to simplify the Hoffmann method and to devise 

 au apparatus which would prove i)rac-tical for laboratories handling a large 

 number of samples of grain. 



14087— No. 99—07 m 2 



