THE BROWN-DUVEL MOISTURE TESTER 43 
(4) The bottom of the flask should be not less than three-eighths 
inch above the wire gauze. 
(5) The column of mercury in the thermometer should be con- 
tinuous ; if broken, it should be shaken down. 
(6) The sample should be thoroughly mixed before weighing for 
tests; and unless the test is to be made immediately upon its ar- 
rival in the office, it should be placed in an air-tight container. 
(7) Tests should be made in duplicate, and if duplicates vary 
over 0.3 per cent, another test should be made. 
(8) The thermometers should be so adjusted that four-fifths of 
the mercury bulb is submerged in the grain and oil after the grain 
has been placed in the flask. (See to the adjustment each time. Do 
not guess.) 
(9) Correctly graduated thermometers and graduates should be 
used. 
(10) Mushy rubber stoppers must not be used as they absorb some 
of the moisture that should pass into the graduates. 
(11) Each graduate should be cleaned and dried before using 
for a test. (Do not let them show any moisture in the bottom or 
along the sides.) 
(12) Oil should not be used directly from the previous test. Used 
flasks should be emptied into a large storage can and never directly 
into the oil-measuring device. 
(13) A good circulation of cold water should be maintained 
through the condenser tank. 
(14) The heating apparatus should be so adjusted that the re- 
quired temperature is reached in 20 minutes. A longer time will 
give results too low and a shorter time, too high. 
(15) If the moisture content of the sample is high so that there 
is a tendency to boil over, the flame should be lowered until a con- 
siderable portion of the water is distilled over. 
(16) The heat should be cut off at the exact temperature prescribed 
for each grain. 
(17) After the flame is extinguished, a slight gradual rise in the 
temperature is to be expected. A sudden increase or sudden decrease 
in temperature of several degrees indicates that the flame was too 
intense during the latter part of the heating, and the test should be 
repeated. 
(18) Covers and thermometers should not be removed until the 
temperature recedes to 160° C. 
(19) After the temperature has fallen to 160° C. or lower, the 
thermometer is disconnected and then the delivery tube. 
(20) The percentage of moisture in the graduated cylinder should 
be read after all the drops clinging to the sides of the graduates 
have been shaken down. The reading is taken beneath the layer of 
oil on top of the water. 
(21) Results of tests need not be expressed more closely than 0.1 
per cent. 
(22) If the water which distills over is discolored, the substance 
has evidently been burned and the test should be repeated. (Note 
exception to this in the case of rice.) 
(23) When machine is not in use, thermometers should be kept 
connected in the flasks and the flasks connected with the distilling 
tubes in the same manner as for making a test. 
