30 
BULLETIN 1375, U. S. DEPARTMENT OF AGRICULTURE 
BULB 
IMMERSION 
'TOO FAST BY; 
TOUCHING I +2.8MIN. 
SURFACE ]e:rroR=-0.4% 
9.8 Minutes 
9.0% Moisture 
Correct Heating Time 
and 
Moisture Test 
wvMim. 
V^^V"; :: ■ ;*» ■*; ; ; :"; ; ; ". ■ iP. -. - U : ; : ;l » ' »-. - 1» " ; 
(CORRECT) I CORRECT 
{TOO SLOW BY l»xX»i[,*ix*»»ii»t*JKiv ' . i > r . < ...,**ii.**.>iii*iij x .ii* xx dii 
-0.3M.N. hr,x^^rx;^;^;;r./^^y/^r.i^r,r.^v,^1 
ERROR = -0.1 ?o 
Total range f°r[ Mo/sTt f re m 0mSX 
l«»x?i| r/eof/ng Time HH ■'- f ° - f J - re 
Fig. 22. — Effect of variations in the depth of immersion of the thermometer 
bulb in the oil on the moisture-test result 
INFLUENCE OF COOLING TIME ON MOISTURE-TEST RESULTS 
"When 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 cause low moisture-test results 
C overs removed 
After tests had 
cooled to 160° C. 
(correct method) 
10 minutes after 
cut-off tempera- 
ture was reached 
(thermometer 
reading 180° C.) 
5 minutes after 
cut-off tempera- 
ture was reached 
(thermometer 
reading 186° C) 
Immediately 
after cut-off tem- 
perature was 
reached (ther- 
mometer reading 
190° C) 
Cooling 
time to 
160° C 
Mois- 
ture 
Cooling 
time to 
160° C 
Mois- 
ture 
Cooling 
time to 
160° C 
Mois- 
ture 
Cooling 
time to 
160° C 
Mois- 
ture 
Average ... ... -. 
Minutes 
mi 
19 
17 
2 
Per cent 
18.3 
18.4 
18.1 
0.3 
Minutes 
16K 
17 
16 
1 
-m 
Per cent 
18.0 
18.1 
17.9 
0.2 
-0.3 
Minutes 
15 2 /3 
15M 
-2U 
Per cent 
17.9 
18.0 
17.7 
0.3 
-0.4 
Minutes [Per cent 
8J£I 17.5 
9 1 17. 6 
7^1 17. 3 
Range . 
1M| 0. 3 
Average variation from cor- 
-10 -0.8 
