132 On the Heat in Forcing-houses. 



Some experiments, which I have made upon germinating 

 seeds, have perfectly satisfied me, that these afford plants of 

 greater or less vigour in proportion as external circumstances 

 are favourable in promoting, beneath the soil, the necessary 

 changes in the nutritive matter they contain ; and I suspect 

 that a large portion of the blossoms of the Cherry and other 

 fruit-trees in the forcing-house often proves abortive, because 

 they are forced, by too high and uniform a temperature, to 

 expand before the sap of the tree is properly prepared to 

 nourish them. 



I have, therefore, been led, during the last three years, to 

 try the effects of keeping up a much higher temperature in 

 the day than in the night ; and as experiments of this kind 

 cannot be made by the common gardener, who must not 

 risk the sacrifice of his employer's crops of fruit, I trust the 

 following account will be honoured by the approbation of 

 the Horticultural Society, though the experiments have been 

 chiefly confined to the Peach tree. 



As early in the spring as I wished the blossoms of my 

 Peach trees to unfold, my house was made warm during the 

 middle of the day ; but towards night it was suffered to cool, 

 and the trees were then sprinkled, by means of a large syringe, 

 with clear water, as nearly at the temperature at which that 

 usually rises from the ground, as I could obtain it ; and little 

 or no artificial heat was given during the night, unless there 

 appeared a prospect of frost. Under this mode of treatment 

 the blossoms advanced with very great vigour, and as rapidly 

 as I wished them, and presented, when expanded, a larger 

 size than I had ever before seen of the same varieties : which 

 circumstance is not unimportant, because the size of the 



