526. Of the larch-tree there are three species: one European and two American. The European larch (Larix Europaea) is a native of the Alps of Switzerland, Italy, Germany, and Siberia, but does not grow on the Pyrenees nor in Spain. The variety from the Italian Alps is the most esteemed, and has been planted to a considerable extent in this country. The larch is a straight and lofty tree of rapid growth, frequently attaining a height of 100 feet. In 1817 a tree of seventy-nine years' growth was cut at Blair Athole, which contained 252 cubic feet of timber; and one of eighty years' growth, at Dunkeld, measured 300 cubic feet; * and a tree of fifty-four years' growth, in Derbyshire, contained 83 1/4 cubic feet.†

According to Hassenfratz the mean size of the trunk is 45 feet in length, and 33 inches in diameter.

It is extremely durable in all situations, failing only where any other kind would fail; for this valuable property it has been celebrated from the time of Vitruvius, who regrets that it could not be easily transported to Rome, where such a wood would have been so valuable. It appears, however, that this was sometimes done; for we are told that Tiberius caused the Naumachiarian Bridge, constructed by Augustus, and afterwards burnt, to be rebuilt of larch planks procured from Rhaetia. Among these was a trunk, 120 feet in length, which excited the admiration of all Rome.* The celebrated Sca-mozzi also extols the larch for every purpose of building; and it has not been found less valuable when grown in proper soils and situations in Britain.

* 'Phil. Mag.,' vol. liii.

† Farey's 'Derbyshire Reporter,' vol. ii., p. 252.

In posts, sleepers, and situations where it is alternately exposed to wet and dry, it is found to be very durable. The Duke of Athole has known it to last from twenty to thirty-four years in such situations, particularly the knotty top-wood.

In countries where larch abounds it is often used to cover buildings, which when first done are the natural colour of the wood, but in two or three years they become covered with resin, and as black as charcoal; the resin forms a kind of impenetrable varnish, which effectually resists the weather.

Larch is not so buoyant, however, nor so elastic as Northern pine, and as it does not dry so completely as pine, boards of it are more apt to warp. It is, however, much more tough and compact, and what are very valuable properties, it approaches nearly to being proof not only against water but against fire, as it does not inflame readily: before a larch beam would be completely charred on the surface, a beam of pine or dry oak will be in a blaze beyond the ordinary means of extinguishment.

Wiebeking says it is preferable to pine, pinaster, or fir, for the construction of the arches of wooden bridges; and Mr. Coxe states, that the borderers on the Lake of Geneva prefer it for building their vessels: indeed the larch is useful for every purpose of building, whether external or internal; it makes excellent ship-timber, masts, boats, posts, rails, and furniture. In some parts of Kamtschatka it arrives at a considerable size, and is there used for ships, and lasts extremely well.† It is peculiarly adapted for flooring-boards in situations where there is much wear, and for staircases; in the latter, its fine colour when rubbed with oil is much preferable to that of the black oaken staircases to be seen in some old mansions. It is well adapted for doors, shutters, and the like; and from the beautiful colour of its wood when varnished, painting is not necessary.

* Beckmann's ' Hist, of Inventions,' vol. ii., p. 299. † Langsdorffs ' Travels,' vol. ii., p. 267.

The chief objections to the wood of the larch are its liability to warp and twist; but this is said to be obviated by barking the trees in spring while growing, and not cutting them down until the following autumn, as suggested by Chapman, or even for a year afterwards. This is also said to prevent the timber from being attacked by the dry rot.

The wood of the European larch is generally of a honey-yellow colour, and the hard part of the annual rings of a redder cast; sometimes it is brownish white. In common with the pine species, each annual ring consists of a hard and soft part. It generally has a silky lustre, the colour is browner than that of the Scotch pine, and the wood is much tougher. It is more difficult to work than Riga or Memel timber; but the surface is better when once it is obtained. It bears driving bolts and nails better than any other kind of resinous wood, and stands well when perfectly dry.

Two distinct varieties of the European larch are found in this country, one being of a redder colour, harder, of a straighter grain, and more free from knots than the other, which is of a white colour and coarse grain. The white kind is the most common. These varieties are supposed to bo caused by some accidental circumstances of soil, site, or impregnation. The author has made experiments on both kinds from the Duke of Athole's woods in Scotland.

In order to try the value of larch as a ship-timber, two ships were built in November, 1820, one of larch from the Duke of Athole's estate, called the 'Athole'; another of Baltic pine, called the 'Nieman.' These vessels, which were both employed on the same kind of service, were examined in

December, 1827, and it was found that the ' Athole' only required a very slight repair, whereas the ' Nieman' was found so very defective that it was proposed to break her up.

The cohesive force of a square inch of larch is from 6000 to 13,000 lbs.

The modulus of elasticity for a square inch is 1,363,500 lbs., and the weight of a cubic foot varies from 29 to 40 lbs. when dry.

The following experiments were made in a Bramah press by Mr. Renton on the resistance to crushing in the direction of the fibres, of larch of average quality, from specimens sent to the author of this work by the Duke of Athole.

Out of the specimens sent by the Duke of Athole, three were selected of average quality, each being 2 inches in breadth, 1 inch deep, and were placed on supports 3 feet apart. A load of 90 lbs. being placed on the middle of each, the permanent set at the end of fifteen hours was only barely sensible.

The first piece broke with 423 lbs.; the second, with 425 lbs.; and the third, with 355 lbs.

From these trials we find that larch bears a stress of 2450 lbs. per square inch without permanent alteration, and an extension of 1/432 of its length. The weight of the modulus of elasticity for a square inch is 1,020,000 lbs. And the weight of a cubic foot when dry is 34 1/4 lbs.

According to Hartig, the wood of the larch weighs 60 lbs. 13 oz. per cubic foot when green, and 36 lbs. per cubic foot when dry.* From experiments made by Mr. Rait, given in Brown's' Forester,' the sap-wood of green larch weighed 48 lbs-per cubic foot, and when dry 32 1/2 lbs. The heart-wood weighed when green 35 lbs., and when dry 31 1/2 lbs. per cubic foot.