142 BOARD OF AGRICULTURE. 



a piston head just as steam does in the steam engine. After it has made a stroke 

 or plunge one way, a valve allows the water to exhaust, or rather leaves it free to 

 return to the tank whence it came, and admits it on the other side for the return 

 stroke. The plunger that forces out the clay is connected to and is in line with 

 the piston, so that the pressure is directly in the line of motion, there being no 

 lateral wear or pressure. A quick return of the plunger, after it has made a 

 plunge, is produced by adding a piece around the piston that is equivalent to in- 

 creasing its size to three-fourths the area of the cylinder, consequently only one- 

 fourth as much water is required to fill that end of the cylinder, and the return 

 stroke is therefore made in one-fourth the time required for the plunge. The tank 

 is conveniently located at the side of the pug mill, and by a cock or valve in the 

 pipe connecting it with the pumps, the speed of the mill can be regulated to any 

 speed, from one plunge in three minutes to four or five in one minute. The stroke 

 of the plunge is readily adjusted to anything under twenty inches. In the pug 

 mill the shaft carrying the tempering blades is hung in a long bearing only at the 

 top end, and goes no further down than the bottom of the pug mill, which is left 

 entirely open for the free passage of the clay into the pressure box. The pug mill 

 runs much faster thau the plunger, and their relative speeds may be so regulated 

 that any clay will be properly tempered before it gets into the pressure box- 

 Another important attachment is a safety valve connected with water pipe that 

 will raise before a breaking strain is reached from any cause. 



They also exhibit the Potts' Geared Brick and Tile Mill. In this the pug mill 

 is the same as the hydraulic. In working the plunger, power is transmitted by 

 gearing to a shaft carrying a large eccentric, with a wide face, that has twenty 

 inches throw ; and a rod from the eccentric strap is connected to and drives the 

 plunger. On thie eccentric shaft is a pair of 52-inch vertical spur wheels, one on 

 either side of eccentric, and a pin tliat has a little play passes throiigli both 

 wheels, near their rims and the eccentric, and serves as an evener to equalize the 

 strain between the two wheels. The band wheel shaft connects to shaft carrying 

 the gearing that drives the eccentric shaft by a clutch coupling, and may be thrown 

 out of gear and the pug mill run alone to temper a mill full to begin on, or to 

 stop it if obstructions get in. All the gearing and bearings about this mill are up 

 out of the dirt, in a convenient position for oiling, none of it being usder the clay. 



They also have a Tile Table on exhibition. This is. an endless belt, made in 

 -sections the length of a tile, with adjustable sides that may be moved out or in, to 

 suit any sized tile, and are held in place by thumb screws. This belt runs over 

 triangular pulleys, tlie axle of the one next the mill being supported by springs 

 that bring the holder up to the tile at once, so as not to mar them. At the de- 

 livery end the triangle sets the tile on end for removing. A very convenient way 

 is provided for raising or lowering the table to the proper height to receive any 

 sized tile. 



Disintegrator for Tile Mills, by Clayton and Albert Potts, Indianapolis. This is a 

 new machine for preparing clay to be tempered in a brick and tile machine, and 

 ■consists of a cast cylinder made in two-inch sections with steel cleats cast in their 



