30 
BULLETIN 1375, U. S. DEPARTMENT OF AGRICULTURE 
BULB 9 B Minutes 
IMMERSION ioXMolsZr* 
(TOO FAST BY /;'■■;.] ..i.i. ..-*. * »,„ 
+ 2.8MIN. ('•• 
ERROR«*0.4% 
Correct Heating Tims 
ond 
Moisture Test 
\ ". i '.".: , : « : w . *. •. « i * •.'.!:;:'«? J , s ; p ; » » »» « » » « j 
CORRECT FOR 
% ] THIS SAMPLE 
(CORRECT) I CORRECT 
[too slow by 
TOTAL I -0.3MIN. 
IMMERSION| ERR0R .. _,j i 
Total range fori"? ''"? *""** ^Jmin 
y \Moisture = 0.5% 
\i*A*V\ rteat,ng Time |^|| Moisture 
Pig. 22. — Effect of variations in the depth of immersion of the thermometer 
bulb in the oil on the moisture- tent result 
INFLUENCE OF COOLING TIME ON MOISTURE-TEST RESULTS 
TThen the flame under the moisture testing flask has been extin- 
guished, the material in the flask must be allowed to cool before 
making the moisture reading, for the reason that moisture will 
continue to distill off the material in the flask for several minutes 
after the flame has been extinguished. In case the moisture reading 
is made before the temperature has dropped to a point at which 
no further moisture will pass into the graduate, the result will be 
inaccurate in that it will indicate less moisture than is actually pres- 
ent. The rate at which the grain and oil in the flasks cool after the 
flame is cut off is also important. Too rapid cooling will cause low 
moisture results, and if the compartment covers are removed too soon 
low results will also prevail. The thermometer reading should drop 
to 160° C, a point where no further accumulation of moisture takes 
place, before the reading is made. Table 7 and Figure 23 sum- 
marize the errors that result if the moisture readings are made pre- 
vious to the thermometer receding to 160° C. 
Table 7. — Insufficient cooling time causes laic moisture-test results 
Covers removed 
After tests had 
cooled to 160° C . 
(correct method) 
Cooling 
time to 
160° C 
Mois- 
ture 
10 minutes after 
cut-off tempera- 
ture was reached 
(thermometer 
reading 180° C) 
Cooling 
time to 
160° C. 
Mois- 
ture 
5 minutes after 
cut-off tempera- 
ture was reached 
(thermometer 
reading 186° C) 
Cooling 
time to 
160° C 
Mois- 
ture 
Immediately 
after cut-off tem- 
perature was 
reached (ther- 
mometer reading 
190° C) 
Cooling 
time to 
160° C 
Mois- 
ture 
Average 
Maximum 
Minimum 
Range 
Average variation from cor- 
rect method... 
Minutes 
19 
17 
2 
Per cent 
18.3 
18.4 
18.1 
0.3 
Minutes 
16H 
17 
16 
1 
-m 
Per cent 
18.0 
18.1 
17.9 
0.2 
-0.3 
Minutes 
1414 
Per cent 
17.9 
18.0 
17.7 
0.3 
Minutes 
■2%\ -0.4 
-10 
Per cent 
17.5 
17.6 
17.3 
0.3 
-0.8 
