69 



parts of this work, vlz.^ to let the former syringing 

 evaporate from the axils of the leaves before supply- 

 I ing more. The fruiters should be allowed a great 

 1 advance of solar heat in the afternoon : the tempera- 

 ture may be safely carried to 80 degs., or even 85, 

 j from three o'clock until five, if by solar heat. 



The only course henceforward is to continue to in-' 

 I crease the heat in a justly corresponding ratio to the 

 ' increase of light ; for this, after all, is the only true 

 standard. Those who can thoroughly understand 

 i this great principle will need few other rules to guide 

 them. 



With increase of temperature, atmospheric mois- 

 ture must also increase, and be made to bear the 

 same relation to heat that heat does to light. These 

 matters being established, the next thing is to watch 

 daily the bottom heat : this has always been an ill- 

 defined matter ; and, instead of laying down any 

 given number of degrees for any period, we would 

 say, to generalize the matter, let the bottom heat be 

 always about 10 degs. in advance of the average at- 

 mospheric temperature ; which latter, as we before 

 observed, will have in the main to be ruled by the 

 amount of light. Thus, in January — 



* See p. 115 of vol. I. for some observations on this point. 



