CHAP. CXIII.

CONI'FEItiE. La'iUX.

2375

than 900 ft. In Switzerland , Kasthoffer informs us, it is found in the highestperfection in soil composed of the debris of calcareous rocks, as well as ingranitic, argillaceous, and schistose soils.

The following admirable remarks by Professor De Candolle 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 generalcircumstances which have an effect on vegetation, that which appears to memost necessary to the larch is, that it have at the same time its roots in asoil habitually, but moderately, damp, and its top exposed to the direct raysof 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 generalobservation of the places where 1 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 mustbe greater to produce the same results. Larches generally thrive on the de-clivities of our mountains, seldom on flat places ; because on declivities thereis 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; whereasflat places are often too dry, and the trees, being all of the same height, over-shadow each other. Among declivities, those which are connected withsummits covered with perpetual snow are those where larches grow best;because there they are slightly and continually watered by the gradual meltingof the snow during summer, and, at the same time, their heads are well exposedto 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 abovethe level of the sea, provided the atmosphere be not obscured by fogs andconstant cloudiness. If the larch seems to like to have its roots in a soilmoderately damp, it likes also to avoid the dampness of the atmosphere. Onthat account, it grows badly near lakes, rivers, cascades, and under the shadeof 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 larchesexisting; yet it does not thrive in our valley, particularly near the lake andthe river. The constant dryness of the air of the Alps is also one of thecauses which makes it prosper there. The dampness of the air tends todiminish the evaporation of the leaves, which is so necessary to the healthand vigour of the tree. It has been remarked that the larch does not growwell 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 surfaceof fresh water, it exhales much moistureinto the atmosphere; 2dly, the wateryparticles which are thrown out by the waves are carried here and there, anddeposited on all solid bodies; and, when the moisture they contain evaporates,it leaves behind a certain quantity of salt, more or less deliquescent (muriatesof lime and soda), which constantly attracts dampness.

“ In Switzerland , the larch grows better in those parts exposed to the norththan to the south. The difference is sometimes so striking, that in thevalleys parallel to the equator, it is not rare to see all the side to the northcovered with larches, and none at all to the south. I am inclined to believethat this arises from the irregularity of our spring, which causes the buds ofthe 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 Ishould say that, if the southern declivities be not too dry, the larches willsucceed better there than here.” (Quart. Journ. of Agr., vol. v. p. 409.)

Sang mentions it as a fact ascertained by experience, that the larch thrivesbest in inland and elevated situations. It will not, he says, “grow up toperfection, even in the best soils, and in situations most favourable to trees in