FLASK FOE DETERMINATION OF WATER IN FLOUR AND MEAL. 7 
quickly withdrawn, so as to see the height of the oil on the thermome- 
ter, which should be so adjusted that the bulb will be three-fourths 
of its length hi the oil. 
(3) A moderate, steady flame should be kept, which will take 15 
minutes for the oil in the inner flask to reach 120° C, 26 minutes for 
the entire test for corn meal, and 30 minutes for flour. If the oil is 
hot between the two walls when the test is begun, the time required 
to reach 120° with a proper flame will be less than 15 minutes. In 
such instances the time from 120° to 150° C. should be approxi- 
mately 6 minutes. 
(4) The thermometer should rise about 5 degrees C. in 1 mmute. 
(5) After the flame is extinguished there is an increase of 10 to 
15 degrees C. in temperature. 
(6) Before taking a reading the distillation flask should be dis- 
connected from the condensing tube and all the moisture allowed 
to collect in the graduate. 
(7) The outside flask can be corked while the inner one is being 
emptied, and the same oil may be used five or six times before being 
changed. 
(8) Cotton should be placed at the bottom of the funnel strainer. 
(9) The inner flask should be rinsed out with an extra 150 c. c. of 
oil after it is emptied of the corn meal or flour. 
(10)- Only special stoppers of the best quality should be used in 
the necks of the copper flasks. 
(11) To insure accurate results when testing flour or meal a special 
measuring graduate should be used. 
(12) For correct results the first run in new flasks should be dis- 
carded and the results of the second one taken; also, if the apparatus 
has not been used for several days, a second run should be made. 
ADDITIONAL COPIES o f this publication 
-i-A. may be procured from the Superintend- 
ent of Documents, Government Printing 
Office, Washington, D. C. ,at 5 cents per copy 
