168 PRELIMINARY REPORT ON COAL-TESTING PLANT, [bull. 261. 
The eggettes of this same mixture that were made on the American 
machine were very hard and had the same metallic ring as the bri- 
quettes. On account of the fragments of coke being crushed in the 
press, these were denser than the briquettes, but not so tough. They 
were, however, very satisfactory. The manufacture of these eggettes 
or briquettes should be a means of utilizing a considerable amount 
of waste coke. 
COKING OF BRIQUETTES AND BRIQUETTE MIXTURES. 
In connection with the briquetting of the various coals, a line of 
experimental work suggested itself, viz, the possibility of making a 
coke out of a semi to non coking coal by the introduction of sufficient 
volatile matter in the form of a binder to cause the coal to coke. The] 
first experiment along this line was tried with some of the briquettes 
made from Arkansas No. 4 coal and 6 per cent of pitch B, by tilling 
a box with about 12 crushed briquettes and then placing this in onei 
of the coke ovens, where it remained during a run of a coking coal. 
The result of this experiment was the obtaining of a mass of coke] 
which was 12 to 15 inches long, somewhat metallic in appearance,] 
and had a good ring to it/' The next experiment was the filling of a 
box with a mixture of Arkansas No. 4 coal with 6 per cent of pitch B,j 
but without passing it through the press. This was treated in the coke 
oven similarly to the other, but the results were not so satisfactory as 
in the first case. A coke was obtained, but it was not so good as the 
other. The next experiment was with the same mixture after briquet- 
ting but without breaking up the briquettes. These were piled on top 
of one another in a box and tested in the coke oven in the same manner 
as the others. The result of this test was the obtaining of masses oi 
coke that retained the form of the original briquette. All of the coke 
obtained by these experiments, while not of the quality desired for 
iron smelting, could be used for lead and copper smelting. 
Another experiment on a larger scale was with 2 tons of Arkansas 
No. 6 slack coal. This coal was mixed with 8 per cent of pitch A and 
then ground in the Williams mill and charged into a coke oven together 
with an equal weight of the same mixture that had been previously 
briquetted. Both mixtures made coke, but not of the best qualitjl 
On account of the briquettes not being packed close together, a portion 
of them were somewhat burned and were not so good as the remainder. 
The experiments seem to show that while a coke can be made bmj 
mixing coal and pitch, coke of a better quality is obtained by pre! 
viously briquetting the mixture; but sufficient experiments along this • 
line have not yet been made to justify any definite conclusions, and it 
is expected that the experimentation will be continued. 
"For coking test .see pp. 130-131. 
