154 PKELIMINARY REPORT ON COAL-TESTING PLANT, [bull. 261. 
although well pressed, black, and lustrous. They weighed on an aver- 
age 6.5 pounds each and had a specific gravity of 1.03. Their crush- 
ing strength was onty 6,000 pounds to the square inch. There was 
little difference in the properties of the eggettes made of this mixture 
and the briquettes. Another ton of this coal was briquetted with 9 
per cent of pitch E, using both sides of the disintegrator with a maxi- 
mum pressure, with the result that a briquette of much better quality 
was obtained. They could, however, have been still further improved 
by the addition of another one-half per cent of pitch. The weight of 
these briquettes was 6.43 pounds each and their specific gravity 1.08. 
Their crushing strength was 9,125 pounds to the square inch. The 
eggettes made from this mixture were equal in strength and quality 
to the briquettes and were much more lustrous and bluish black in color. 
Another test was made with Illinois No. 4 coal and pitch H, which I 
is a by-product from the manufacture of gas from heavy petroleum. 
While this pitch would be rather soft to work on the English machine; 
on a hot day, it is readily cracked and mixed on a cold day. One tonj 
of the coal was briquetted with 8 per cent of pitch H, and the resultant 
briquettes were very strong, clean, and satisfactory, being very much 
better than any of the other briquettes made with this coal. They 1 
were readily handled when taken from the machine, and when cold 
were very hard and tough, and were capable of standing a great deal 
of rough handling. Their average weight was 6.81 pounds each andl 
their specific gravity was 1.11. Their crushing strength was 12,810 
pounds to the square inch, this being the greatest of all the briquettes 1 
made from Illinois coal. 
The last test made with this coal was with a soft asphalt received 
from the Gulf Refining Compai^. In freezing weather this asphall 
became hard enough to crack and thus could be used on the English, 
machine. On account of the cold weather, there was considerable 
water in the steam, which produced cracks. Because of this fac 
and the low melting point and thinness of the asphalt while hot, tl 
briquettes were difficult to handle as they came from the machine 
They were, however, well pressed and on cooling became tough an 
would stand much handling. A better result can probably be obtaine 
by using a small percentage of rosin with the asphalt. 
INDIANA. 
Two coals from this State were tested more for comparative pu 
poses than with regard to their commercial possibilities. 
Indiana No. 1. — Four tons of this coal were briquetted with 7 p< 
cent of pitch D. a The coal was first washed and then dried. The bi 
quettes were brown in color, readily handled as they came from tl 
machine, and when cold stood rough handling. The average weig 
a For results of steam test see p. 80. 
