FLASK FOR DETERMINATION OF WATER IN FLOUR AND MEAL. 
STOPPERS TO BE USED. 
If copper flasks are used, a special No. 5 rubber stopper will have 
to be made, so as to stand the high temperature. Figure 7 shows the 
results of the heat on three rubber stoppers when run in a double- 
walled copper flask. The temperature of the oil 
in the inner flasks in each of these tests was 190° 
C. when the flame was extinguished. Stopper A 
was made especially to stand high temperatures and 
was tested once ; stopper B was also especially made 
by the same manufacturer who made stopper A, but 
was tested 30 times, while stopper C is the regular 
No. 5 stopper and was tested only once. It is im- 
portant that a special stopper which will stand high 
temperatures be used if flour and meal are run in 
the copper flask. 
Vp 
HOW TO TEST DIFFERENT SUBSTANCES. 
The methods used in testing flour and corn meal 
are as follows: 
Wheat flour. — Use 1-50 c. c. of oil both in the 
inner flask and between the two walls and 50 
grams of flour in the inner flask. Extinguish the 
flame when the temperature reaches 190° C. The 
oil in the inner flask should reach 190° in about 
30 minutes. 
Corn meal.—JJse 150 c. c. of oil both in the 
inner flask and between the two walls and 50 
grams of corn meal in the inner flask. Extin- 
guish the flame when the temperature reaches 
175° C. The oil in the inner flask should reach 
175° in about 26 minutes. 
TIME OF TEST. 
I 
\ 
yr. 
Fig. 4.— G raduated 
measuring cylinder, 
showing 13.2 per cent 
of moisture. 
One of the most important factors 
in getting correct results in the test 
here described is the time in which it is made. Unless the 
flame is under the direct control of the operator and run 
in accordance with the following directions, the test will 
not be accurate. 
The flame should be so adjusted that the temperature 
of the oil in the inner flask will reach 120° C. in 15 minutes 
and rise approximately 5 degrees for every minute after 
that until it reaches the desired temperature. This will require 14 
minutes for oil containing flour after it gets to a temperature of 
120° to reach a temperature of 190°, and 11 minutes for oil contain- 
ing meal after it gets to a temperature of 120° to reach a tempera- 
ture of 175°. If the oil in the inner flask reaches a temperature of 
Fig. 5.— Test 
tube cleaner. 
