ON THE APPLICATION OF MANURE IN A LIQUID FORM. 213 



A single orange- tree was subjected to the same mode of treatment, 

 and grew with equal comparative vigour, and appeared to be as much 

 benefited by abundant food as even the vine and mulberry tree. 



An opinion generally, though I think somewhat erroneously, prevails 

 that many plants, particularly the different species and varieties of heath, 

 require a very poor soil in pots; but these might, I conceive, with 

 propriety, be said to require a peculiar soil ; for I have never seen the 

 common species of this genus spring with so much luxuriance as from a 

 deep bed of vegetable mould, which had been recently very thickly covered 

 with the ashes of a preceding crop of heaths and other plants that had 

 been burned upon it. And I believe, if the branches and leaves of the 

 common species of heath were placed to decompose in water, and such 

 water were afterwards given to the tender exotic species, that these, 

 how heavily soever the water might be loaded with organisable matter,, 

 would be found as little capable of being injured by abundant food as the 

 vine or mulberry tree, though the species of food which would best suit 

 those plants might prove to every species of heath destructive and 

 poisonous. 



XXX. ON THE ILL EFFECTS OF EXCESSIVE HEAT IN FORCING-HOUSES 

 DURING THE NIGHT. 



[Read before the HORTICULTURAL SOCIETY, June 17 th, 1814.] 



FEW gardeners, if any, have ever believed plants to be at all endued 

 with powers of sensation and perception similar to those of animals ; or 

 to be, in any degree, susceptible of pleasure or pain ; and yet it is very 

 questionable whether there has ever been a single gardener, who, in the 

 management of fruit-trees in a forcing-house, did not in some respects 

 err by treating his trees as he would have done, if he had supposed them 

 to possess such powers. Being fully sensible of the comforts of a warm 

 bed in a cold night, and of fresh air in a hot day, the gardener generally 

 treats his plants as he would wish to be treated himself; and, conse- 

 quently, though the aggregate temperature of his house be nearly what it 

 ought to be, its temperature during the night, relatively to that of the day, 

 is almost always much too high. The consequences of this excess of heat 

 during the night are, I have reason to believe, in all cases highly injurious 

 to the fruit-trees of temperate climates, and not at all beneficial to those 

 of tropical climates ; for the temperature of these is, in many instances, 



