158 PRELIMINARY REPORT ON COAL-TESTLNO PLANT. [BTJLL.26li 
quettes were black and clean and only slightly streaked with the clay. 
When piled up they stuck together slightly, and were mottled a little 
from the creosote. They have, however, much less of the gray efflor- 
escence than any of the Indian Territory No. 6 briquettes that have 
thus far been made, and are also the best that have been made, although 
still earthy. They are smooth and black, and although crumbling 
but little or not at all in handling, on breaking for firing they will 
crumble a great deal. The eggettes, on the other hand, made of this 
same mixture on the American machine are just as strong and would 
need no breaking in firing. The weight of these briquettes was 7.21 
pounds each on an average. The specific gravity was 1.215, and their 
crushing strength was 6,500 pounds to the square inch. 
Another test with the Indian Territory No. 6 coal was with the 
asphalt B5, which during the cool weather had become hard enough 
to crack, and thus could be readily used on the English machine. Ona 
ton of this coal and 8 per cent asphalt were used, which made brj 
quettes that were soft and hard to handle while warm, especially when 
they contained moisture due to the wet steam. The better ones werd 
compact, heavy, and tough, and although they had an earthy, oiljj 
appearance, did not crack when struck a severe blow. They would 
stand rough handling, but would be improved with a small percentage 
of rosin. These briquettes weighed 7.12 pounds each, and had a spe- 
cific gravity of 1.22. Their crushing strength was very low, averaging 
3,200 pounds per square inch. In making the compression tests the 
briquettes yielded a great deal before breaking and would be stronger 
under a quick load. The results varied from 1,800 to 5,100 pounds. 
On obtaining a sample of pitch H it was decided to try the effect o: 
this pitch on the Indian Territory No. 6 coal. The best results wer<r| 
obtained with this as a binder. One ton of coal was mixed with 8 pe 
cent of pitch H, and with nearly dry steam and good pressure the; 
made hard, compact briquettes. Although somewhat earthy, the; 
would stand rough handling. Their average weight was 7.27 pound, 
each. 
IOWA. 
Iowa No. If. — One ton of this coal was briquetted with 7 per cent c 
pitch E. The briquettes were well pressed, of a grayish color, but o 
cooling crumbled decidedly. They weighed 6.73 pounds each. A 
they did not contain an excess of pitch, 7 tons more of this coal wei 
briquetted with 8 per cent of pitch E, in order to have a sufnciei 
quantity for a steam test." The resultant briquettes were bluish blac 
in color, but they were not quite hard enough, although fairly stron; 
and would stand considerable hard treatment in transportation. J 
burning the}^ held together until consumed. They weighed, on i 
a For result of this test see p. 81. 
