CHAP. CXIII. COVI'FBRJE. ZA N UIX. 2375 



than 900 ft. In Switzerland, Kasthoffer informs us, it is found in the highest 

 perfection in soil composed of the debris of calcareous rocks, as well as in 

 granitic, argillaceous, and schistose soils. 



The following admirable remarks by Professor DeCandolle show the neces- 

 sity of a clear and dry atmosphere, and a soil somewhat moist on the surface, 

 to the prosperity of the larch as a timber tree : — " Amongst all the general 

 circumstances which have an effect on vegetation, that which appears to me 

 most necessary to the larch is, that it have at the same time its roots in a 

 soil habitually, but moderately, damp, and its top exposed to the direct rays 

 of the sun, so that the evaporation of water, and the decomposition of car- 

 bonic acid, may go on with activity. I support this opinion, 1st, on general 

 observation of the places where I see the larch prospering ; 2dly, on theory. 

 The larch has fine and minute leaves, and, of all trees which shed their leaves, 

 it must present a less surface; consequently, the action of these surfaces must 

 be greater to produce the same results. Larches generally thrive on the de- 

 clivities of our mountains, seldom on flat places ; because on declivities there 

 is always a little dampness in the earth, descending from the surface above ; 

 and, at the same time, the trees, on account of the inequality of their bases, 

 have more space at their tops, and are better exposed to the light ; whereas 

 flat places are often too dry, and the trees, being all of the same height, over- 

 shadow each other. Among declivities, those which are connected with 

 summits covered with perpetual snow are those where larches grow best ; 

 because there they are slightly and continually watered by the gradual melting 

 of the snow during summer, and, at the same time, their heads are well exposed 

 to the sun. Declivities, and, in general, elevated countries, suit larches best ; 

 because the action of the light is more intense there than in low countries : 

 yet the larch succeeds well enough in situations only a little elevated above 

 the level of the sea, provided the atmosphere be not obscured by fogs and 

 constant cloudiness. If the larch seems to like to have its roots in a soil 

 moderately damp, it likes also to avoid the dampness of the atmosphere. On 

 that account, it grows badly near lakes, rivers, cascades, and under the shade 

 of rocks, even in those countries where, in other situations, it would flourish. 

 We are here (Geneva) very near the countries where the larch grows beauti- 

 fully. We are at a height superior to that where we know of fine larches 

 existing; yet it does not thrive in our valley, particularly near the lake and 

 the river. The constant dryness of the air of the Alps is also one of the 

 causes which makes it prosper there. The dampness of the air tends to 

 diminish the evaporation of the leaves, which is so necessary to the health 

 and vigour of the tree. It has been remarked that the larch does not grow 

 well near the sea, which proves what I have just advanced. The sea pro- 

 duces an increase of dampness in the air in two ways: 1st, like the surface 

 of fresh water, it exhales much moisture into the atmosphere ; 2dly, the watery 

 particles which are thrown out by the waves are carried here and there, and 

 deposited on all solid bodies ; and, when the moisture they contain evaporates, 

 it leaves behind a certain quantity of salt, more or less deliquescent (muriates 

 of lime and soda), which constantly attracts dampness. 



" In Switzerland, the larch grows better in those parts exposed to the north 

 than to the south. The difference is sometimes so striking, that in the 

 valleys parallel to the equator, it is not rare to see all the side to the north 

 covered with larches, and none at all to the south. I am inclined to believe 

 that this arises from the irregularity of our spring, which causes the buds of 

 the larches to be too precocious on the southern declivities; and, consequently, 

 they are frequently killed by the frost. In the latitude of Great Britain, 

 where the spring is more regular, I think this cause will not operate ; and I 

 should say that, if the southern declivities be not too dry, the larches will 

 succeed better there than here." (Quart. Journ. o/Agr., vol. v. p. 409.) 



Sang mentions it as a fact ascertained by experience, that the larch thrives 

 best in inland and elevated situations. It will not, he says, " grow up to 

 perfection, even in the best soils, and in situations most favourable to trees in 



