674: NEW YOKE STATE MUSEUM 



The principle of burning is mucli tlie same in the different kilns, 

 but the burning can be better regulated in closed kilns. In down- 

 draft kilns the bricks in the upper portion of the kiln receive 

 the greatest amount of heat, whereas in a scove-kiln or clamp, the 

 arch bricks, which have to bear the weight of the overlying bricks, 

 are heated the most and often become crushed out of shape. The 

 rectangular can not be bound together as well as circular kilns, 

 this being of course necessary in order to prevent a bulging of the 

 walls during burning. 



Most of the manufacturers who make common bricks by the soft 

 mud process, bum them in temporary, up-draft kilns, or scove- 

 kilns, as they are properly called, but the use of kilns of the Endaly 

 type as well as continuous ones is extending rapidly. 



Scove-kilns. In these the bricks are set up and burnt in " arches ", 

 several of which go to make up a kiln. The number of bricks in 

 an arch varies from 35,000 to 40,000. An arch is about 40 courses 

 high, and about 15 arches make up a kiln. The open portion of 

 the arch is about 14 courses high; the bricks above the arch are set 

 three one way and then three on top at right angles. They are 

 kept slightly separated by putting small pieces of clay between 

 them. The first row of brick on top of the arch is called the tie 

 course, and the first 14 couraeB, including the tie course, above the 

 arch are called the " lower bench ", and the rest of the courses above 

 are called the " upper bench ". When the arch and lower and 

 upper benches have been set, brick are laid flat over the top of the 

 kiln; this is the "raw platting"; and then on top of this is laid 

 burnt bricks at right angles to those of the raw platting, which is 

 the " burnt platting ". Hanging from the roof of the kiln shed 

 at the same level are a number of bricks which serve as a guide for 

 hight in building the kiln. A wall of two thicknesses of " double- 

 coal " brick is put around the outside of the kiln, scoving the Idln 

 it is called, and this is " daubed " over with mud. The daub is to 

 prevent any air entering except through the doors. The latter con- 

 sist of an iron frame about 14 inches high, with an iron plate to 



