24 
EXPERIMENTAL WORK IN FUEL TESTING. 
Determinations of ash, sulphur, and specific gravity — Continued. 
Designation of coal sampled. 
Pennsylvania No. 10.. 
Tennessee No. 2 
Tennessee No. 3 
Tennessee No. 4 
Tennessee No. 6 
Tennessee No. 7 A 
Tennessee No. 8 A 
Tennessee No. 10 
Texas No. 3 
Texas No. 4 
"Virginia No. 1 A 
Virginia No. IB 
Virginia No. 2B 
Virginia No. 3 
Virginia No. 4 
Washington No. 1 B... 
Washington No. 2 
West Virginia No. 4 B. 
We>t Virginia No. 13.. 
West Virginia No. 14. . 
West Virginia No. 15. . 
West Virginia No. 16 A 
West Virginia No. 16 B 
West Virginia No. 17. . 
West Virginia No. 18. . 
West Virginia No. 19. . 
West Virginia No. 20. . 
West Virginia No. 21. . 
Wyoming No. 2 B 
Wyoming No. 3 
Wyoming No. 4 
Wyoming No. 5 
Wyoming No. 6 
Car sample. 
Ash. Sulphur 
6.17 
6.81 
7.05 
9.53 
14.43 
12.85 
13.42 
59.14 
7.88 
7.30 
4.73 
5.01 
5.58 
4.48 
4.33 
11.37 
12. 26 
7.76 
3.91 
3.27 
8.55 
5. 57 
8.37 
8.12 
5.83 
5.01 
8.03 
4.85 
20. 79 
16. 70 
6.77 
3.41 
3.12 
1.26 
.98 
.99 
.98 
.78 
3.26 
4.38 
.21 
.99 
.51 
1.20 
1.11 
.92 
.67 
.79 
.72 
.38 
.81 
.89 
1.03 
2. 54 
1.06 
1.20 
1.45 
.67 
.89 
1.38 
1.32 
4.03 
6. 66 
.26 
.81 
.49 
Specific gravity. 
Selected ! Average 
lumps. lumps. 
1.30 
1.28 
1.29 
1.29 
1.29 
1.34 
1.34 
1.35 
1.36 
1.33 
1.32 
1.37 
1.31 
1.39 
1.37 
1.27 
1.27 
1.28 
1.27 
1.28 
1.28 
1.32 
1.31 
1.27 
1.27 
1.28 
1.30 
1.28 
1.28 
1.30 
1.26 
1.27 
1.28 
1.31 
1.2S 
1.33 
1.26 
1.28 
1.25 
1.26 
1.30 
1.34 
1.37 
1.28 
1.28 
1.33 
1.39 
1.35 
1.30 
1.28 
1.31 
1.37 
1.34 
1.41 
1.34 
1.38 
1.34 
1.34 
1.37 
1.40 
1.35 
1.30 
It is obvious from the foregoing table that the specific gravity of 
the lumps of coal is considerably affected by the amount of impurities 
contained. Even the selected lumps were not free from ash and sul- 
phur, so that it is not possible to obtain the true specific gravity of 
the pure coal itself. 
In order to further investigate the relation of impurities to specific 
gravity, five of the coals in the foregoing table were selected as repre- 
senting the great diversity of character. These coals were separated 
first into sizes and then each size, except the dust, was further sepa- 
rated by "float-and-sink" tests upon heavy solutions, of 1.35 specific 
gravity calcium chloride and 1.45 and 1.65 specific gravity zinc chlo- 
ride. The procedure in detail was as follows: 
The coal, after crushing till it all passed a i-inch screen, was sifted 
over a series of sieves— 80 mesh, 40 mesh, 10 mesh, and 4 mesh. That 
passing the first two screens was designated ' w dust•, ,, that passing the 10 
mesh and retained on the 40 mesh was designated u fine; 1 ' that passing 
the 4 mesh and retained on the 10 mesh " medium," and that retained 
on the 4 mesh " coarse." The dust was not separated on the solution, 
but each of the remaining classes was then stirred in a solution of 1.35 
specific gravit\ T , and the floating coal was removed, washed, and air 
dried. That sinking in this solution was then washed, dried, weighed, 
and stirred in a solution of 1.45 specific gravity, and the floating coal 
treated as before; and the process was again repeated in a solution of 
