RESULTS OF AIR DRYING. 9 
to time and the drying continued until the weight remained almost 
constant. The air-drying loss of these samples and the loss in weight 
of the corresponding regular samples dried in the dryer, with the 
amount of moisture remaining in the dryer samples, are tabulated 
below. In most of the samples the dryer loss is not widely different 
from the loss on the air-dry sample. Special exceptions are Nos. 1960 
(Indiana No. 9 B) and 1390 (Wyoming No. 6), on which samples the 
dryer-sample loss is decidedly larger than that on the samples dried 
by exposure to the air of the laboratory. The samples dried during 
the summer months were exposed to air of a high average humidity 
(60 per cent), as the temperature and humidity of the laboratory were 
approximately that of the outdoor air for that period. The samples 
dried during the winter months were exposed to air of low average 
humidity (30 per cent), as the temperature of the laboratory was 
decidedly higher than that of the outdoor air, with approximately the 
same absolute amount of moisture present in the laboratory and in the 
outdoor air. The humidity of the warmer laboratory air is conse- 
quently low. The percentage of moisture remaining in the samples 
dried by exposure to. the air of the laboratory was determined by 
adding or subtracting (according to whether it was plus or minus) the 
difference between the loss in the dryer and the loss in the exposed 
sample to the moisture remaining in the " dryer sample," as given in 
the table below: 
Results of tests for moisture in samples of coal. 
Sample of coal. 
Labora 
tory 
num- 
ber. 
3'294 
3255 
3308 
3331 
3406 
2626 
3315 
3295 
2332 
2572 
2420 
3307 
2528 
2264 
3286 
3405 
1761 
1876 
3225 
2896 
1960 
2686 
2731 
2803 
3390 
Field number. 
New Mexico No. 5 
Alabama No. 3 
New Mexico No. 3 
New Mexico No. 4 A 
Indian Territory No. 2 B.. 
West Virginia No. 20 
New Mexico No. 4 B 
New Mexico No 3 A 
West Virginia No. 17 
West Virginia No. 21 
Virginia No. 1 
New Mexico No. 3 B 
Kentucky No. 5 
West Virginia No. 16 B.... 
UtahNo.l 
Indian Territory No. 2 B .. 
Illinois No. 15 
Indiana No. 6 
Wyoming No. 5 
Illinois No. 22 B 
Indiana No. 9 B 
Washington No. 1 B 
Illinois No. 20 
Illinois No. 23 B 
Wyoming No. 6 
Moisture in sample. 
As re- 
ceived. 
Per ct. 
2.72 
2.72 
2.75 
2.78 
2.81 
2.89 
3.38 
3.45 
3.46 
3.57 
4.06 
4.36 
4.36 
5.57 
5.83 
6.27 
9.95 
10.47 
11.44 
13.03 
13.53 
14.30 
14.68 
15.68 
19.00 
Loss on coarse 
sample, as 
dried— 
By ex- 
posure. 
Per ct. 
1.60 
0.30 
1.40 
0.40 
60 
1.98 
1.60 
1.50 
2.07 
2.24 
2.59 
2.20 
1.77 
3.89 
2.30 
4.20 
3.62 
6.02 
4.10 
9.74 
7.13 
8.12 
11.80 
13.98 
7.50 
In 
dryer. 
Per ct. 
1 40 
1.20 
1.40 
1.40 
1.40 
1.90 
1.70 
2.00 
2.50 
2.10 
2.40 
3.00 
2.80 
4.40 
2.10 
4.90 
4.20 
6.30 
3.70 
11.20 
.10. 70 
9.60 
12. 40 
13.20 
11.30 
A'fter drying- 
By ex- 
posure 
(calcu- 
lated). 
Per ct, 
1.14 
2.44 
1.37 
2 40 
2. 23 
0.93 
1.81 
1.98 
1.43 
1.36 
1.51 
2.20 
2.63 
1.73 
3.61 
2.14 
6.58 
4.73 
7.64 
3.52 
6.74 
6.68 
3.20 
2.08 
12.48 
In 
dryer. 
Per ct. 
1.34 
1.54 
1.37 
1.40 
1.43 
1.01 
1.71 
1.48 
1.00 
1.50 
1.70 
1.40 
1.60 
1.22 
3.81 
1.44 
6.00 
4.45 
8.04 
2.06 
3.17 
5.20 
2.60 
2.86 
8.68 
Time of 
drying 
by ex- 
posure 
Bays. 
17 
13 
19 
14 
16 
16 
18 
17 
11 
12 
9 
19 
10 
11 
. 17 
16 
18 
14 
21 
8 
18 
9 
11 
10 
16 
Air of labora- 
tory. 
Tem- 
pera- 
C. 
25 
25 
25 
24 
26 
21 
25 
25 
21 
19 
25 
25 
24 
18 
25 
26 
27 
27 
25 
23 
27 
22 
23 
24 
27 
Humid- 
ity. 
Per ct. 
63 
64 
63 
62 
64 
26 
62 
63 
47 
28 
27 
63 
31 
57 
63 
64 
64 
64 
53 
35 
67 
28 
34 
31 
64 
6128— Bull. 323— 0/ 
