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STATE AGRICULTURAL SOCIETY. 
earth. In fact, when the clay is literally dry, some moderate 
degree of moisture must be artificially imparted to it; and this 
is accomplished, in Wilson’s British process, by passing the 
material through a steam-cbamber. On the other band, when 
the season is wet, or when the natural source from which the 
clay is derived is always wet, it is necessary to diminish the 
amount of moisture ; an effect which is most easily secured 
by keeping a supply of dry clay under cover to mix with that 
which comes from the bed too highly charged with moisture. 
For the purpose of forming solid brick for building, the dry 
process is preferable, on account of the facility and safety with 
which the moulded masses may be handled and immediately as 
they come from the moulds, without being liable to be deformed 
or distorted; and also because of the saving of the time which 
must be allowed, in the case of ^ the wet-moulded brick, for 
drying. This drying j)rocess is moreover attended with a neces¬ 
sary exposure to the weather; and rains very often occasion 
serious damage when they occur during its continuence. 
Gregg's Brick-Pressing Machine .—At the exposition of 1867 
the machine which seemed to be the mo^t in favor was that of 
Mr. Isaac Gregg of Philadelphia,in which the brick are formed by 
the dry process with great rapidity. This machine was doubly 
exhibited, being presented in model in the palace, and in 
actual operation in the neighborhood of the Champs de Mars, 
during all the period of the exposition. The material after 
being screened and crushed, is elevated into a hopper, from 
which it is admitted alternately on opposite sides into the 
moulds, where it is powerfully compressed and delivered di¬ 
rectly to the attendants to be conveyed immediately to the 
furnace. The brick, after burning, present a perfectly uniform 
and compact appearance. Their surfaces are smooth, their 
forms entirely regular, and their tenacity remarkable. 
Hartel's Plastic-Clay Brick Machine .—Quite a variety of ma¬ 
chines were exhibited in which clay in the plastic form is the 
material used. Of these a very striking one was from Men- 
burg in Prussia, the invention of Mr. Hartel. The descrip¬ 
tion of this machine, as given by the inventor, represents it to 
