344 GEOLOGY OF OHIO. 
inches in height and 5 feet deep at each attack. The machine is shifted 
over three feet and a second attack made, and so on until the whole 
room has become undermined to a depth of five feet. An undercutting 
of 100 lineal feet is regarded as a fair day’s work for one machine. In 
some mines the undercutting is made in the fire-clay floor, and all the 
coal is saved; in other mines it cannot be used in the floor. | 
The Harrison coal-cutter was first applied in the mines of Illinois, 
by the Diamond Coal and Mining Co., and in 1880, the Chicago, Wil- 
mington and Vermillion Coal Co. of the same State, one of the wealthi- 
est mining corporations in the west, applied 10 of these coal-cutters, and 
they soon found their way to Ohio mines. The coal-cutter consists of 
a pick 8 pounds weight and 10 inches long, operated by a piston. The 
pick, which is made of,solid steel, has two points, and undercuts the 
coal in much the same way as the miner does. This machine is much 
lighter, and is more easily moved about than the Lechner, but it effects 
no saving of coal over the ordinary method of hand-mining. Both 
machines have their advocates, and either of them is an improvement . 
over manual labor. A few months ago the Harrison machine was in- 
troduced into the iron ore mines of the Hanging Rock region, and will 
prove a more successful digger of iron ore than of coal. 
The introduction of coal-cutting machinery was looked upon with 
a jealous eye by the miners, and yet it will come not as their enemy, 
but as their best friend. It will not drive out the miner, but will 
lighten his occupation, and give him brain labor. It will take away 
the laborious work of undercutting, at once the most constrained and 
exhausting work to which the human frame can be put. The floor of 
mines is always damp, often wet, and the miner is required to lie down 
on his side, and burrow away underneath the coal for 4 or 5 feet. Lum- 
bago and rheumatism attack him in consequence. 
A large number of coal cutting machines have been introduced 
from time to time into the mines of Great Britain. Only a few of them 
have been found in practice to hold their own. Coal, the foundation 
of the power which sets the machinery of the world in motion, has been 
found one of the most difficult industries to which can be applied 
labor-saving machinery. 
