CLAY WORKING INDUSTRIES. 113 



very brief description will be given of each type and as nearly as possible 

 the consensus of opinion, in regard to their qualities, from those who are 

 best situated to know. 



The Akron Sqziare Kiln, the most widely used of any one kind in the 

 stoneware business, is a rectangular structure about fifteen wide by thirty 

 feet long outside. The inside dimensions are about twelve wide by eight- 

 een or twenty feet long; the roof is a groined arch, about seven feet 

 above the floor at the spring and ten feet at the center. The peculiarity 

 of the kiln is that it is fired at the ends exclusively. There are either 

 two or three fire holes at each end, opening inside the end wall of the 

 kiln into a common combustion chamber the full width of the kiln and 

 about eighteen inches wide. This combustion chamber is formed by the 

 erection of a fire wall or flash wall across the kiln, parallel with the end 

 wall and extending from the floor to within about twelve or eighteen 

 inches of the spring of the arch. This combustion chamber becomes the 

 hottest part of the kiln and it greatly assists in the combustion of the 

 flames and smoke from the fires and keeping the reducing influences at 

 a minimum. The kiln has a cross flue in the center leading to a stack on 

 one side or the other. This stack for one kiln need not be twenty-five 

 feet high by four square feet internal area, but is usually made three or 

 four feet wide by six or eight feet area. The floor of the kiln is checker 

 work, allowing free passage of the gases into the side flues, which run 

 from end to end of the kiln joining the main flue at the center. The 

 door is in the center of one side. The kiln may be built double with only 

 one wall between two kilns. The strong points in favor of this kiln are: 



1. The compact form, and the small amount of yard room which it 

 requires ; this is a great advantage in grouping kilns closely around the 

 factory so as to make short distances to handle the unburnt wares. 



2. The common combustion chamber, through which the gases 

 must pass before entering among the wares, reduces the liability to 

 smothered or dark colored ware as much as is accomplished in any down- 

 draft burning kiln. 



3. The fire holes are capable of very close regulation and get more 

 of the gas producer effect than any fire hole in use in the stoneware busi- 

 ness. 



4. The kiln is considered the "safest" one for large wares, on account 

 of the heat being introduced wholly at the ends which causes the middle 

 of the kiln to always hang back in burning, and large pieces being set in 

 the middle, have the greatest time to get up to the finishing heat. 



5. It is easy to set and draw, as the courses of ware are all straight 

 and at right angles to the long way of the kiln. 



On the other hand, the following points are against : 

 1. The cost of the kiln is high. The brick work is more in quantity 

 for the capacity of the interior than in the round kiln and the strength of 

 the bracing and bridging required to hold the roof up is excessive. The 



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