taps or valves, so long (even with filtration) did we experience
difficulties with the flow of viscous tar. But on the construction of
valves specially designed for the regulation of its flow, the difficulty
immediately disappeared, and there is no longer the slightest trouble on
this account. The labor connected with the feeding of furnaces with coke
and cleaning fires from clinker is of a very arduous and heavy nature.
Eight coke fires are normally considered to be work for one man. A lad
could work sixteen of these tar fires.


COMPOSITION OF FURNACE GASES.

Considerable attention has been paid to the composition of the furnace
gases from the tar fires. The slightest deficiency in the air supply, of
course, results in the immediate production of smoke, so that the damper
must be set to provide always a sufficient air supply. Under these
circumstances of damper, the following analyses of combustion gases from
tar fires have been obtained:

No Smoke.
CO_{2}. O. CO.
11.7 5.0 Not determined.
13.3 3.7 "
10.8 5.4 "
14.8 2.5 "
13.5 3.0 "
12.4 5.6 "
12.4 4.6 "
13.1 5.9 "
15.3 1.0 "