318 FORGING GARDEN. 



coal is carbonized, that is, the gas is separated from it 

 and inflamed, leaving onlj coke. . The strong combus- 

 tion of the coke at the grate produces heat enough to 

 carbonize the coal^ and air enough to inflame the gas. 

 This furnace, therefore, not only consumes most of the 

 smoke, but eifects a considerable saving of fuel. 



Steam. — Of late years steam has been applied with 

 success to the production of an artificial climate in 

 glazed houses. It is more genial than fire-heat from 

 flues, being less contaminated, and more equable and 

 pliant in its distribution. In steam hot-houses, the plants 

 can scarcely ever be liable to suffer from scorching 

 heat ; the air continues pure and untainted, and per- 

 sons visiting the house are much less liable to be an- 

 noyed by the smell of smoke and soot. It is neater in 

 all its arrangements within doors and also without, for 

 it precludes the necessity of more thaji one furnace, and 

 one chimney-top, and in a great measure removes the 

 unseemliness of the heaps of coals and ashes with which 

 common furnaces are usually surrounded. In districts 

 where coals are dear, the saving of fuel is an object ; 

 and it has been found that seven bushels of coals go as 

 far in keeping up steam heat as ten bushels do in main- 

 taining an equal temperature in the ordinary way. By 

 merely opening a valvcj the house may at any time be 

 effectually steamed^ that is, filled with the steam or va- 

 por, and the warm moisture thus applied to the plants 

 is observed to contribute remarkably to their health 

 and vigor. To counterbalance these advantages, we 

 are not aware of any defects, except such' as may arise 

 from the greater complexity of the apparatus, or at 

 least its liability to disrepair and accident. - 



Steam is generated in a cast or wrought iron boiler, 



