RATT.] 
fcRIQUETTlNG TESTS. 
139 
>ercentage of volatile matter give the best results in briquetting. 
['here may be, however, a wide variation in the percentage of the 
volatile matter in two pitches made from different tars and distilled 
inder different conditions and yet the pitches may have approxi- 
nately the same quality for binding purposes. 
In order to obtain something more tangible regarding the composi- 
ion of the pitches in respect to their binding qualities and value in 
>riquetting, a series of tests was made 'by distilling off thin volatile 
products. For this purpose a small copper still was constructed and 
lie distillations were made in the laboratory of Dr. Herman von 
5chrenk. in carrying out these experiments, 200 grams of the pitch 
vere placed in the still, and this was heated gradually until there was 
lothing left but a coke residue. In every instance at a temperature 
)f 400° ail of the volatile matter had been driven off and the residue 
vas hard coke. The results of these distillations are given in the 
able below: 
Distillation of pitches. 
Pitch. 
Labora- 
tory No. 
Quantity 
of pitch 
used. . 
Tempera- 
ture at 
which 
first drop 
came 
over. 
Tempera- 
ture at 
which the 
last di' the 
oil was 
observed 
to come 
off. 
Percent- 
age of oil. 
Final 
tempera- 
ture to 
which 
still was 
raised. 
Residue. 
Grams. 
O 
o 
o 
1161 
1311 
1465 
1464 
1453 
1125 
200 
200 
200 
200 
200 
200 
380 
351 
332 
350 
324 
391 
3S5 
375 
370 
382 
1.36 
7.38 
13.01 
1.91 
.96 
.71 
400 
400 
400 
400 
400 
400 
Hard coke. 
Do. 
> 
Do. 
Do. 
Do. 
Do. 
The above experiments show that from 7-k to 14 per cent of these 
ils is necessary in the pitches in order to give them the binding 
ualities that are desired in briquetting. With a higher percentage 
f oils the pitches become too soft and can not be used to so good 
dvantage. Then again, the oils that are driven off from 315 and 
nder are the creosote oil.3. Creosote was used to mix with some of 
ie hard pitches for binding purposes and gave satisfactory results. 
ROSIN. 
The cheaper grades- of rosin can be used for binding purposes to as 
oocl advantage as the refined material, and, as far as could be judged 
•om the work done in the laboratory, the crude, black rosin will give 
good satisfaction as the partially refined. Rosin in some cases can 
