160 PRELIMINARY REPORT ON COAL-TESTING PLANT. [bull.2< 
made of this same mixture were very hard and sonorous, but rath* 
too brittle. In the cook stove the eggettes burned veiy satisfactorily 
This coal was tested with 8 per cent pitch E, using 3i tons of co 
and giving the briquettes the greatest pressure possible on the Englii; 
machine. a As the coal is very hard, only one side of the disintegrate 
was used, and in the resultant briquettes there were many large pieci 
of coal, but there were also sufficient small pieces to fill in all the opei 
ings between the larger fragments. This is a nearly ideal conditio 
for briquetting on the English machine. The briquettes were bluis 
black and excellent in every way. They did not have the glossy < 
lustrous fracture of the briquettes containing 9 per cent of pitch, bi 
they were a better commercial briquette and were more easiby handle 
when taken from the machine. With pitch of the quality of pitch D < 
pitch II, from 5 to 6 per cent would make a good briquette. These bi 
quettes would stand a great deal of rough treatment in transportatioi 
and in burning they did not disintegrate, nor was there much slac 
formed in breaking them for burning. They weighed on an avera^ 
6.83 pounds each and had a specific gravity of 1.13, as compared wit 
1.37, the specific gravity of the slack or fine coal. The slack whic 
was used in making the briquettes contained 18 per cent of ash, bi 
the lump coal contained only 11 per cent of ash. The crushing strengi 
of the briquettes was 11,300 pounds to the square inch. The eggett< 
made from this same mixture were stronger and better than thoi 
made with 9 per cent, although not so sonorous and hard. They we: 
also browner in color. The eggettes were not so strong as tl 
briquettes. 
MISSOURI. 
Missouri No. 1. — At the time this coal was tested only the hard pit 
was available. Two and a half tons of this coal that had been pi 
viously washed were briquetted with 11.5 per cent of pitch A. T 
resultant briquettes were black in color and sufficiently hard to sta 
rough handling, but on account of the pitch setting too quickly th 
were insufficiently pressed and were granular and porous. h This c<< 
will, however, briquette very readily, and with the softer pitches, 
pitch D and pitch H, will make a good briquette with about 6 to 7 ] 
cent of binder. 
MONTANA. 
Montana No. 1. — This coal was dried slightly 7 before briquetti 
It was tested with 16 per cent of pitch A. The full limit of press 
that could be obtained on the English machine was used, and althoi 
the briquettes were well pressed, they were somewhat porous : 
rough on the surface. They were black, but not very glossy. J 
a For results of steam test see p. 81. b For steam test see p. 81. 
