By Thomas Andrew Knight, Esq, 201 



than can subsequently be given, is always exceedingly in- 

 jurious, in unnecessarily expending the excitability of the 

 plants. Every year's experience shows how much better 

 seedling plants grow in spring, than in autumn. In the 

 former period, the intensity of light is increasing ; in the 

 latter it is decreasing, as it would be in a house constructed 

 according to Mr. Wilkinson's recommendation, as far as 

 inclination of roof would operate, from the 6th of April to 

 Midsummer. 



Mr. Wilkinson's next objection is, that the inclination of 

 roof, which 1 recommended, admits most light and heat 

 when they are " least requisite:* Every gardener must know, 

 that fruits are always best, when heat and light are very 

 intense, during the period in which they are ripening, and 

 that heat and light are then most requisite. 



But it is not on the 21st of July only, that an inclination 

 of roof of 34 degrees admits most light. I contend that 

 the reflexion of light continues to diminish, as the solar rays 

 fall more perpendicularly, and that this inclination admits 

 more light, between the 20th of April and the 20th of Au- 

 gust, than any other whatever. During this period the 

 Vines blossom and ripen their fruit, in a Vinery : they also 

 form the buds, and blossoms, for the succeeding season; 

 and within the same period they probably generate the sap 

 which feeds the blossoms, and leaves, and young shoots, of 

 the following spring * On the 4th of September, the leaves 

 in a Vinery are nearly out of office ; and a vertical sun can 

 do little at that period, but wither the remaining crop of 

 mature fruit. 



* See Philosophical Transactions of 1805, Part I. 



