HOT WATER AND STEAM. 173 



a regular manner. The difference between the 

 actual temperature and that of the dew point, is 

 least in January, and increases gradually till 

 June, when it again declines to its winter state. 



Having studied with considerable care and 

 attention the effects of the atmospheric air in 

 all its relations to vegetation,, it has brought me 

 to the conclusion, that the internal air of a 

 forcing house is less liable to suffer by hot watei 

 heat ; being almost free from any noxious efflu- 

 via which may arise from other heating ; more- 

 over it is a dry heat, which is essential to the 

 ripening of fruit, and yet when necessary, a fine 

 dew may at any time be raised in the house by 

 watering over the pipes when heated. 



Although I have spoken thus much in praise 

 of hot water heating, let me not be understood 

 by so doing, to underrate the heating by flues, 

 which has stood the test, and proved so emi- 

 nently successful for generations past ; but de- 

 cidedly I am of opinion, that for general forcing, 

 hot water is the most convenient, safe, and eco- 

 nomical mode of heating extant ; added to which, 

 it is with very little trouble, and in a very short 



