CLAYS OF NEW YOEK 



661 



sliaking. The inclined screens are usnallj 10 to 14 feet long, liave 

 a bottom of either wire cloth or perforated metal, and are usnally 

 provided with a tapping device to keep them from becoming 

 clogged. Such screens are simple and cheap, but have a small 

 capacity. 



The rotary screens are commonly of wire cloth, and have a 

 cylindric or octagonal form. They are usually provided on the 

 inner side with brushes to keep them clean. 



Shaking screens are fixed at one end, while to the other end is 

 attached a crank and piston or an eccentric, which operates them. 

 Such screens are cheap and simple in operation. 



"While all of these screens are designed to perform their work 

 automatically, nevertheless very few of them can be left without 

 attention for any length of time, for powdered clay, no matter how 

 dry it is apparently, shows the greatest tendency to clog the meshes 

 of almost any screen. 



Molding 

 Soft mud process 



This is the most prevalent method in ISTew York state. 



The clay is mixed with water to the consistency of a soft mud, 

 and is 'either forced into a wooden mold by hand, or molded in a 

 machine, operated by steam or horse power. 



There are a number of different types of machines but the funda- 

 mental principle of all is the same. A soft mud machine consists 

 essentially of an upright box of'^wood or iron and generally of a 

 rectangular shape. In this is a vertical shaft bearing several knives 

 horizontally. Attached to the bottom of the shaft is, a device such 

 as a curved arm, which forces the clay into the press box. The 

 molds are put in at the rear of the machine and fed forward under- 

 neath the press box automatically. The empty mold sliding into 

 place sliovea out the filled one. The molds before being placed in 

 the machine are sanded either by a boy, or else in an automatic 

 mold sanding machine in order to prevent the clay from sticking. 

 The clay is fed to the machine at the upper end of the box. Often 



