PEAT. 533 



masses, coated with a spongy bark capable of detaining moisture with 

 great force. On the contrary, they are, as has leen already stated, 

 delicate hair-like fibres, whose bark is little more protection to 

 them than the skin of a leaf. Such being their structure, they are 

 emptied of whatever fluids they may contain when the earth in contact 

 with them becomes dry ; and if in a growing state" they necessarily 

 perish. All those directions, therefore, which insist upon keeping the 

 level of American beds below the surrounding surface, when the 

 situation is not naturally damp, are founded upon a correct appreciation 

 of the nature of these plants. Why calcareous matter in excess 

 should be offensive to them we are unable to explain. Such is the 

 fact ; and it is probable that the reason why the American plants at 

 Knap HUl and Bagshot are finer than any in the valley of the Thames, 

 is on account of the great abundance of lime in the water of all the 

 latter district. It appears from analysis that while London water, that 

 is to say Thames water, contains 16 grains of lime in a gallon, Bagshot 

 water contains only oiie grain, or less. The true difficulty, then, in 

 growing American plants, is not the want of proper soU, for that may 

 be made, but the want of a sufficient supply of pure water ; and it may 

 be a question whether a very material difference would not be found in 

 those places where American plants grow badly if rain-water alone were 

 used in watering them, instead of that from pumps and ditches. 



It is as well to observe that the peat from bogs is not suited to garden 

 purposes, until it has been rotted down by long exposure to weather, or 

 by the action of lime or caustic ammonia (gas water). This is owing 

 to the large quantity of free aoetic acid and tannin in its composition, 

 which renders it unfit to support vegetation till the acid is neutralised 

 and the tannin decomposed. Another way of rendering it a fit sub- 

 stitute for the upland peat, which gardeners prefer, is to ferment it in 

 a heap, mixied with stable litter ; if moistened with gas water, so much 

 the better ; in a twelvemonth it is fit for use, with the addition of loam 

 and about 80 per cent, of sUver sand. 



When we see that the Box-tree, the Fig-tree, the shrubby 

 Bwplewum delight in chalky hUls, it is inferred that chalk is 

 necessary to those plants. But they will also grow in clay, 

 though not so well ; and it is possible that they may prefer the 

 hills they live on, because they are hot and dry, not because 

 they are calcareous. Elyrlms arewarms lives in blowing sand ; 

 but it may occupy that soil because of its extreme looseness and 

 dryness, not because of its being siliceous. Epiphytes do not 

 grow in earth ; apparently because the peculiar organization of 

 their roots renders them impatient of having those parts 

 covered ; and they prefer the branches of trees to rocks, not 



