alternation is the most trying of all circumstances for the endurance of timber, and accordingly the oaken posts decayed, and were twice renewed, in the course of a very few years, whilst those which were made of larch remained altogether unchanged. We had ourselves occasion to erect a footbridge to carry a pleasure walk over a sunk road, and this we ordered to be constructed of two long stretching beams, covered transversely with larch planks. In fourteen or fifteen years afterwards we discovered symptoms of decay in the bridge, and ordered the carpenter to new plank it; but when he came to carry our directions into execution, he discovered that the whole planks were quite sound, with the exception of three, and that these three, which were rotten almost to powder, were Scotch fir planks, which had been taken, in a hurry, at the time the bridge was built, to supply a deficiency in the original number of the larch planks. "The larch," says Mr Sang, "bears the ascendancy over the Scotch pine in the following important circumstances: that it brings double the price, at least, per measurable foot; that it will arrive at a useful timber size in one half or a third part of the time, in general, which the fir requires; and, above all, that the timber of the larch at thirty or forty years old, when placed in soil and climate adapted to the production of perfect timber, is in every respect superior in quality to that of the fir at a hundred years old."

Some experiments were made at Woolwich, under the Duke of Athol's direction, by Messrs Barrallier and Peake, on the average and relative strength of larch as compared with two other descriptions of firs, the result of which was the following:

Average strength. Relative strength.

Mr Tredgold, the celebrated engineer, also made experiments on the comparative strength of Athol larch, Riga fir, Memel fir, and English oak. These results first appeared in Tilloch's Philosphical Magazine, in March, 1818.

The pieces were each an inch square, except No. 3, which was only 8-10ths of an inch in breadth. The numbers in

the Table shew the weights it would have borne if it had been an inch square; the pieces were supported at each end, and were loaded by putting 5 lb. at a time into a scale suspended from the middle, - the distance between the supports were thirty inches.

As the strength of small pieces depends much on the position of the annual rings, the pieces were placed as nearly alike in this respect as possible. When the pieces were in the position in which they were broken, the dark lines, or portions of the annual rings that appear in the section of a piece, were vertical. From the results exhibited in the preceding table, it appears very clearly that larch is best adapted to resist the force of a body in motion.

But to leave no doubt of the superior resilience of larch timber, the following experiments were made. These were performed by Mr Tredgold, in the presence of his Grace the Duke of Athol, Mr Atkinson, architect to the Ordnance, and others.

The pieces were each an inch in depth, and they were laid upon supports, thirty inches apart. The weight fell between two vertical guides, (similar to a pile engine,) upon the middle of the piece.

No. 11. was a dark coloured, and apparently very strong piece of wood; specific gravity 0.872, or 54 lb. per cubic foot. On the whole, then, it appears that larch is superior to oak in stiffness, in strength, and in the power of resisting a body in motion, (called resilience;) and it is inferior to Memel or Riga timber in stiffness only.

Larch may be used for all the purposes for which the best foreign hard pine timber is used, and for many of those of oak. A good many trading vessels have been built in the Moray Firth, and especially at Findhorn, of larch grown within these fifty years on the neighbouring estates, and, so far as we can learn, these have all given most perfect satisfaction. The only objection this timber has, is, that it is liable to warp and cast; but this evil might perhaps be prevented by giving the logs a sufficient time to season, for, it must be observed, that, so far as its endurance is concerned, it will last just as well by being cut from the forest and put directly into the work, one of its qualities which, we suspect, may lead to the circumstance of its having obtained a character for warping, which, if otherwise treated, it might not

deserve. The larch also possesses another property, which it shares with the oak, we mean the tanning powers of its bark; and we are disposed to believe that its value in this department is as yet only half appreciated.

Though we should least expect to find such a quality in a resinous tree like the larch, it has been proved to make a beautiful hedge, and to submit with wonderful patience to the shears. We once saw a very pretty fence of this description in a gentleman's pleasure ground near Loch Lomond. The trees were planted at equal distances from each other, and being clipped, were half cut through towards the top, and bent down over each other, and, in many instances, the top shoot of one had insinuated itself into that adjacent to it, so as to have become corporeally united to it; and, strange as it may seem, we actually found one top that had so inserted itself, which, having been rather deeply cut originally by the hedgebill, had actually detached itself from its parent stock, and was now growing, grafted on the other, with the lower part of it pointing upwards into the air!

Of the Pinus larix, there is a variety with red, and another with white flowers; one with cinereous bark, called the Russian Larch, and one with pendulous branches. There are also the Black Larch, Pinus pendula, and the Red Larch, Pinus microcarpa, natives of America, by some considered distinct species.

The larch is much infested, in this country, with the insect peculiar to it, which we shall call the Chermes Pini. The male of this insect is an active winged fly, whilst the female is without wings, and one of the most inert of the things possessed of life. The female is generally found adhering to the axillary angles of the last year's buds, like a brown scale. It lives upon the resinous sap of the tree, which it seems to pump up by inserting its proboscis into the bark, and the resinous matter exudes, in a floculent and white state, from certain tuberculated pores in the thorax, abdomen, and cauda, covering the creature with what, to the careless observer, looks like a woolly or cottony substance. When the period of its oviposition arrives, it attaches the eggs to the bark, one by one as they are excluded, by minute resinous filaments, spun from a mamellary protuberance in the breast. It lays eighty or a hundred eggs, or more, of a long kidney shape, and the attaching filaments are applied to the ends of them, so that, when one is touched by a delicate instrument, the whole are thereby put in motion. It appears that instinct

teaches the insect to leave that end of the egg at liberty, where the head of the pupa lies, and the wonderful provision of the Great Creator of the universe is such, that the heat necessary for the perfection of the enclosed pupæ, and that for the growth of the young shoot of the tree from the bud, being exactly equal, the shoot has no sooner reached that size and state which renders it fitting food for the infant animals, than they are ready to burst their cerements, and to travel upwards to revel on its juices. The pupæ have six legs, and are extremely active. Our examinations of these creatures were minute, and frequent, and long continued, and our observations many; but we have not room to give them in detail here. We may remark, however, that in the vast plantations which we subjected to our inspection, in many of which the trees were whitened with them, as if by a hoar frost, we could discover but two or three individual larches which appeared to be actually killed by the operations of the Chermes Pini, though many were manifestly much retarded in their growth by their operations. But their havoc was dreadful on the silver firs, of which we shall have occasion to speak anon. In the Alps, we could not detect the insect at all, except, we think, on one occasion, and then a few individuals merely were observable on one tree. The planters of larch were at one period very much alarmed at the evils which they anticipated from the devastations of this insect; but from all we have seen, we are inclined to think that the effects of their ravages are little to be apprehended.

Before proceeding with Mr Gilpin to the consideration of the evergreen trees, we think we ought to notice one or two deciduous trees which he has overlooked, but which must find a place either in the forest, the park, or the pleasure ground.

The Prunus avium, of the class and order Icosandria monogynia. The Wild Cherry, or Guigne, may very well be called a forest tree, seeing that, in many parts of the wilds of Scotland, it is almost as numerous, and propagates itself as fast, as the birch; it grows, moreover, to be a very handsome timber tree, and the wood of it makes very pretty furniture. In form, it is oftener graceful than grand; and its foliage is rather too sparse to produce that tufty effect which gives breadth of light and depth of shadow enough to please the painter's eye. But on the cliffs of romantic rivers, such as the Findhorn, and other Scottish streams of the same character, where it is stinted of soil, it often shoots from the crevices of