274 APPLICATION OP PRINCIPLES. 



cess. The effect that is really produced upon thein 

 is, to give them a sort of artificial winter in summer, 

 that is, to expose them to a period of comparative 

 rest from growth, which, in many cases, is useful. 

 The best method of counteracting tbe injurious 

 35 effects of exposure to the air is 



> by employing double pots {fig. 

 35), as recommended in the 

 Gardener's Magazine, ix. 576, 

 and by Captain Mangles, in his 

 Floral Calendar, p. 44 ; the space 

 (b) between the two pots being 

 filled up with moss, or any other 

 substance retentive of moisture. 

 Of course the inconveniences now alluded to are 

 principally sustained by plants in small pots : when 

 the quantity of earth is considerable, as in tubs or 

 the largest kinds of pots, the loss of water through 

 the sides is of little moment ; and the variation of 

 temperature is more than counteracted by the large 

 surface exposed to the direct influence of the solar 

 rays. In these cases, the perfect drainage of super- 

 fluous moisture is often of the greatest service. Mr. 

 Knight, indeed, assures us that " plants of every 

 species are more or less affected, but not all inju- 

 riously, by having the sides of their pots exposed 

 fully to the air. The taste and flavour of the peach 

 and nectarine, and still more of the strawberry, are 

 greatly improved; and the Pig-tree, in the stove, 

 is made to afford a longer succession of produce, 

 owing to the succession of young shoots, which are 



