CULTIVATION. 



237 



exhaust is provided. The air admitted to the drying 

 chamber enters through p^pes or other channels, debouch- 

 ing near the heating apparatus and fitted with valves or 

 dampers for regulating the supply. 



The earliest hop kilns were built in England and 

 America. They were fitted with open fireplaces, which 

 were afterwards converted into closed stoves. English kili^s, 

 with enclosed fireplaces are now largely in use, and are 

 generally of square or circular section. 



Fig. 66.— The Karl hop kiln. 



The drying floor of the kiln is covered to a depth of abOut 

 8 inches with green hops, which are turned once during the 

 eleven or twelve hours required for drying. 



The Karl hop kiln^ , shown in Fig. 66, and used in 

 Bohemia, is fitted with portable drying frames (hurdles), and 

 differs mainly from the English type of kiln in the more 

 convenient arrangement of the heating apparatus and drying 

 floor. 



1 Uhland's 2'echnische Rundschau, 1898, No. 7. 



