970 GEOLOGY OF OHIO 
good merchantable lump coal. The common charge of an oven is 100 
to 110 bushels of coal, weighing 76 lbs. or 4 tons; the time of coking, 
37 to 38 hours. | 7 
This coke is very largely used in Western Pennsylvania, Eastern 
Ohio, the iron works of Illinois and Missouri, and is even carried to 
the silver and lead smelting works of Utah, Nevada, etec., where it costs 
from 25 to 30 dollars per ton. Its value at Pittsburgh varies but little, 
and is from 6 to 7 cents per bushel, or about $3.50 per ton. It is de- 
livered in most places in Central and Eastern Ohio at a price of from 
$3.50 to $5.00 per ton, so that often in some localities it is less expen- 
sive than the local fuels. The composition of the Connellsville coke 
has been given on page 559, where it will be seen to contain a high 
percentage of ash—about 11 per cent. This is too large a proportion 
for a good iron smelting fuel, and it will probably not be long before 
some method of purifying the coal will be demanded. ‘The high repu- 
tation that it holds is probably due largely to its uniformity, its hard- 
ness and fine appearance, though the sulphur present is rarely below 
1 per cent. 
In England the round ovens are almost the only form used. They 
are often arranged with an exit flue in the rear part of the vault, for the 
escape of the gases into a common conduit, through which they pass to 
a single large chimney, a hole being also left in the center of the roof 
for charging, but which is closed during the operation. A damper 
placed in the flue from each furnace, its connection with the main con- 
duit and chimney may at any time be severed. 
Furnaces of this type are sometimes made oval, elliptical or rect- 
angular, with doors at either end of the longer diameter for discharg- 
ing, and an opening in the roof as in the ordinary bee-hive for charg- 
ing. This form, though once quite common, is now not very extensively . 
employed. At St. Etienne, France, furnaces of this character, with an 
elliptical hearth, are 15 to 18 feet long, 83 to 93 feet wide, and 3% to 4% 
feet high, with an opening in the roof for charging about 18 inches in 
diameter, and a door at both ends for discharging. The charge of coal 
is from 2.6 to 4% tons, and the time of coking 24 to 48 hours, the opera- 
tion being conducted as in the common bee-hive oven. 
A similar form of oven is used at Seraing, Belgium, in which the 
application of the waste heat of the gases is made to generate steam. 
They are arranged in a battery of 8 furnaces together, supporting a 
