508 GEOLOGY OF OHIO. 
“Monitor” furnace, four miles from Ironton, the mantel being supported - 
_ by iron pillars, so arranged as to allow freer access to the tuyers. 
The hearths are mostly built of sandstone, and the upper lining 
of the furnace, of fire-brick. The sandstone for the hearths is found in 
abundance in various places in the carboniferous beds. The stones 
under Coal No. 4, under the gray limestone, between the block ore and 
ferriferous limestone, and from other localities, are reported as used at 
different furnaces. These stones being easily worked, and very refrac- 
tory, wear well. The fire-bricks for lining are obtained from various 
manufactories in the district, or from several of the well-known firms 
of Pennsylvania and the east. The tuyers in the cold-blast furnaces 
are generally simple iron nozzles not protected by water; wherever the 
blast is heated at all, the ordinary coil-pipe or plain iron water-tuyer 
is used ; the diameter of the tuyers in the cold-blast furnaces is generally 
from 33 to 4 inches. The blast pressure is low, usually from 3 to 33 
pounds or a little higher in the hot-blast furnaces. 
Many of the furnaces are provided with blowing-engines in which 
the steam-cylinder is connected with the blowing-cylinder by means of 
gearing or large cog-wheels, so arranged that the steam-cylinder makes 
from 13 to 2 strokes for each stroke of the air-cylinder ; actual numbers 
are 17 of the steam-cylinder, 8% of the air-cylinder ; 18 steam-cylinder, 
12 air-cylinder (strokes per minute). The steam-cylinders are 18 to 20 
inches in diameter, the blast-cylinder is 44 in. by 5 ft., 48 in. by 6 ft., 
36 in. by 4 ft. These figures, taken from furnaces in blast, serve to 
indicate the average. The tuyer is generally set in the hearth at from 
one-half to two-thirds its height; the deep hearth being rather charac- 
teristic. 
The furnaces being bank furnaces, no hoist is usually required. In 
some cases, as at the “ Grant” furnace at Ironton, a water-hoist is used, 
consisting of a wooden tower in which the elevator runs suspended by 
wire cables; the arrangement for raising and lowering consisting of a 
tank placed in the bottom of each of the two cages, and so arranged 
that when the cage is up, this can be filled with water lifted by a pump 
through a connecting pipe.’ The increase of weight thus given brings 
down the empty cage, and lifts the full one; on reaching the bottom 
the tank empties automatically through an opening in the bottom, which 
is closed by a valve connected with a stem, which opens it when the 
cage is down. ‘These old water-hoists are curiosities in the way of fur- 
