710 \ GEOLOGY OF OHIO. 
brief outline to make them familiar to all. The largest and best regulated 
establishment visited is that of A. O. Jones & Co., Columbus, and from 
that place this sketch was taken. The clay is dug in a 6-foot stratum, 
just in rear of the factory, and is carted into the works and dumped 
into a bin beside the grinding machine. It is here wet down with,a hose 
to the right point, and is then shoveled into the grinder. This consists 
of two parallel, horizontal rolls revolving towards each other at a dis- 
tance of ¢ inch apart. 
On the surface of these rolls are small, gradual depressions and 
elevations which are arranged on both sides of the center as spirals to- 
ward either end. Any particle of hard matter over $ inch diameter 
will not catch in the smooth, slippery roll, but by the special motion of 
the alternating ridges and depressions will be carried off on either side 
and dropped into an appropriate receptacle, while all clay and soft mat- 
ter is crushed and deposited on the belt which runs underneath the 
machine. On this belt it travels to the “auger” machine, into which it 
is delivered. 
The grinder is run at high speed and has no trouble in cleaning 
enough clay for one large machine to use. The ‘“ auger” machine so 
often alluded to, consists of a cylindrical shell of iron-plate, inside of 
which works a screw or auger. A hopper at one end catches and col- 
lects the clay as it comes from the grinder, and it is dropped upon the 
revolving screw—it is caught up and carried forward and is soon forced 
out at the other end through the orifice in the die. The machine has a 
set of dies from 2 inches to 12 inches, and can make any size at will. 
Besides the circular tile, by alterations in the die, fire-proofing, square 
tile, perforated brick, etc., can be made. There are a great many styles 
of auger machines in use. That made in Tecumseh, Michigan, by Brewer 
& Co., is a good one, also machines made at Bucyrus, and at Cuyahoga 
Falls are of good reputation. The shaped clay issuing from the 
machine is cut in lengths and put on the shelves of an elevating belt. 
It is received on the upper floors and set on end on the drying floors, 
of which there are four, all made of slat-work to allow circulation of 
heat. The roof imprisons the hot air from the engine and boilers, so 
that the temperature constantly ranges from 90° to 120°. The drying 
takes from one to three days, by which time the tile is quite hard. The 
census of 1880 gives Ohio a pre-eminence in this manufacture. The 
value of drain tile made in 1880 was $834,918.00, about 43 times as 
