NIGHT TEMPEKATUKE TO BE KEPT DOWN. 519 



The last experiment being carried still further, by observa- 

 tions continued during a part of another month, the result 

 remained the same, the total growth by night being 119.07, 

 and by day 337.16. Thus we see that plants exposed to 

 natural circumstances only made one inch of growth by night 

 while they made three by day ; but that, on the contrary, 

 under bad artificial treatment, they grew equally day and night. 

 The inevitable consequence of this inversion of natural 

 growth is immature or unripe wood, with imperfect iU- 

 constructed buds, and a feeble constitution, incapable of bearing 

 the shock of great falls in temperature. More especially, water 

 accumulates in the system, and is never decomposed or removed 

 by perspiration, in the requisite degree. In short, plants 

 growing fast by night can neither ripen their wood nor form 

 their inner structure weU. And therefore they are incapable 

 of developing their natural beauty, or of resisting those 

 extremes of temjferature which are natural to them. 



This seems to explain why our greenhouse plants would 

 perish under the night temperature to which they are exposed 

 in New Holland. They are in the condition of a Peach-tree 

 kept growing fast in a forcing-house, and turned out for the 

 winter without having ripened its wood: if that is done it 

 dies, and yet the Peach-tree, when properly ripened, is capable 

 of resisting much severer winters than England ever knows. 

 An Oak-tree, treated in the same way, would be as tender. 



If, however, the English gardener cannot command an 

 ItaUan or Australian sun, if he cannot expose his plants for 

 days together to a temperature of 100° — 115°, and if, therefore, 

 he cannot harden their tissues, and strengthen their constitu- 

 tion so as to enable them to bear the rudeness of their native 

 land, there are other things which he can do. He can keep 

 down their growth at night, he can maintain among them 

 continual currents of air, and having done this skilfully he will 

 have done aU that the circumstances of his position render 

 possible. 



It wiU be apparent from these remarks that gardeners are 

 not recommended to freeze their greenhouse and stove plants, 

 because they are frozen habitually in Australia, and occasionally 



