242 FOREST PRODUCTS 



5. Its location should be on soil which is rather dry and soft, and 

 preferably clay or calcareous soil. 



Special kilns or ovens have been devised and have .been used in con- 

 nection with or near large iron furnaces. They did not seek at first the 

 recovery of the volatile products of wood, but were the medium or step 

 between the crude old-fashioned open-air charcoal pit and the modern 

 wood distillation plant. They have largely gone out of existence at the 

 present time, owing to the much greater profits to be derived by the 

 construction and operation of the distillation plant. They were usually 

 of conical shape, about 24 ft. in diameter, about 25 to 30 ft. in height 



Photograph by U. S. Forest Service 



FIG. 65. Type of brick beehive kiln used for making charcoal for iron furnaces in northern 

 New York. Photograph taken at Wolf Pond, Franklin Co., New York. These had a 

 capacity of about 40 cords each. 



and had a capacity of about 40 cords of wood. They were commonly 

 called " beehive " ovens. They were lined with fire brick up to 10 to 12 

 ft. on the inside, and were plastered on both inside and outside. Air 

 holes were provided around the base of the kiln and at the top was an 

 iron door which could be raised and lowered as desired. 



Another form of rectangular shape, about 40 ft. long, 16 ft. wide and 

 15 ft. high, usually held about 80 cords of wood at one charge, and pro- 

 duced about 3000 bu. of charcoal at one time. 



The yield by both these forms is usually from 37 to 46 bu. of char- 



