246 VARIOUS METHODS OF HEATING DESCRIBED IN DETAIL. 



air onwards to the other end of the flue, and thence through tin, 

 zinc, or any other kind of pipe placed there to convey it away. 

 By these means it is conducted (i. e., the heated air from the 

 box) into the different stoves and green-houses. Each house, 

 or, rather, each compartment, is provided with a supply-pipe and 

 a tap, by which heated air is admitted by measure, and of course 

 regulated according to the requirements of the plants. We 

 could not clearly ascertain the exact size of the fire-place, but 

 we saw some iron pipes, which we were told were similar to 

 those in use in the fire-place for heating the air, and we sup- 

 posed them to be about six inches in diameter. These pipes, 

 as they are exposed to the action of a strong fire, become greatly 

 heated, and the air, in passing through them, becomes intensely 

 hot and dry, consequently, deprived of its oxygen and aqueous 

 properties. Here, however, no evaporating pans are used for 

 moistening the warm air, as in common hot-air furnaces, and 

 the method adopted for supplying the heated air with moisture 

 is quite as novel as the system itself. To effect this, a steam 

 jet is played into the hot-air flue, immediately before it enters the 

 different compartments, and Mr. Hooibrink, the gardener to 

 Baron Hugel, stated that he admitted the steam according to 

 the nature of the plants cultivated in each apartment. Thus, 

 he allowed so many feet of steam for his orchards ; so many for 

 his stove plants, and so many for his common green-house 

 plants ; thus each kind of plants is supplied with steam, 

 according as it requires a moist or dry atmosphere. 



" Thus, if we are rightly understood, there is, first, a large fire- 

 place ; through this fire two or more cast-iron pipes, six inches 

 in diameter, are passed ; they are so placed as to be subjected to 

 the most intense action of the caloric produced by combustion ; 

 one end of these pipes is exposed to the external atmosphere, 

 the other ends enter a large oblong box, on a level with the 

 pipes, in which is placed a fan, similar to those used in small 

 fanning mills. This fan is made to revolve with considerable 

 rapidity, by the power of a small steam-engine, drawing the 

 atmospheric air inwards through the tubes exposed to the fire, 

 and forcing it onwards through the main conductor, and thence 

 into the smaller tubes leading to the right or left, up or down, 



