26 



On Climate, $t 



hot-houses during the severe season: and in the spring, 

 when they are wanted for other purposes, their places might 

 be supplied at night by mats or canvass. 



The principles which I have been endeavouring to illus- 

 trate should be doubtless extended to the Pinery and the 

 Melon frame, in the latter of which a saturated atmosphere 

 might be maintained by shallow pans of water. An increase 

 in the size of the fruit might be anticipated from this treat- 

 ment, without that loss of flavour which would attend the 

 communication of water to the roots of the plants: 



I have but few additional observations to offer upon the 

 artificial climate of a green-house. The remarks which have 

 been made upon the atmosphere of the hot-house are ap- 

 plicable to it ; though not to the same extent. The plants 

 which are subject to this culture seldom require an artificial 

 temperature greater than 45° or 50°, and few of them would 

 receive injury from a temperature so low as 35°. When in 

 the house they are effectually sheltered from the effects of 

 direct radiation, which cannot take place through glass : but 

 the glass itself radiates very freely, and thus communicates a 

 chill to the air, which might effectually be prevented by 

 rolling mats. With this precaution, fire would be but rarely 

 wanted in a good situation, to communicate warmth. But in 

 this damp climate it may be required to dissipate moisture. 

 The state of the air should be as carefully watched with this 

 view, as where a high temperature is necessary, to guard 

 against the contrary extreme. Free transpiration, as J have 

 before remarked, is necessary to the healthy progress of vege- 

 tation, and when any mouldiness or damp appears upon the 

 plants, the temperature of the air should be moderately 



