There is one circumstance connected with this timber in this country, at least in Scotland, which must prevent its general use in ship plank, and be of material injury to it for ship timbers; this is, that few trees of it of size are found without the timber being shaky or split, some to such a degree that the annual rings or concentric growths have separated from each other. This appears to be owing to our climate being colder than what is suitable to the nature of the plant; the sap in the stem possibly freezing in severe weather and splitting, or severing the growths of the timber, but more probably occasioned by the season being too short, and too moist and cold, to ripen or fill up with dense matter, sufficiently, the frame of the annual growths; thence, as each ring of sap-wood, prematurely hastened by the torpor of moisture and cold, turns to red or matured wood, and, in so doing, dries considerably within the other rings of moist sap-wood, the contractile force may be sufficient to separate this growth from the next external sap growth, the cohesion existing between the tissue or fabric of the growth being much stronger than the cohesion between one {45} growth and another. The uncommon dryness of the matured wood, and moistness of the sap-wood of this tree, and smallness of the number of sap-wood rings, commonly only from 2 to 6 in this country, incline us to believe that this is the cause of the insufficiency or defect; and that, in a milder, drier climate, the sap-wood rings will be found to be more numerous, and thus, independent of a better first ripening, affording a longer time for their cells to be more filled up with an unctuous matter (which prevents the shrinking) gradually deposited while they convey the sap, the sap-wood rings being the part of the timber through which the sap circulates. As proof of this unctuous deposit or filling up, we observe that dry sap-wood imbibes moisture much quicker, and in greater quantity, than dry mature. We think this premature maturity (if we may so term it) of timber in cold countries, a general law. Our larch, originally from the Apennine, has not more than one-third of the number of sap-rings of our Scots fir, indigenous in Mar and Rannoch mountains; and our narrow-leafed, or English elm, said to have been introduced from the Holy Land in time of the Crusades, has not more than one-half of the number of our indigenous broad-leafed, or Scots elm. From the sap-growths of Laburnum, {46} scarcely exceeding in number those of the Spanish chestnut, we should suppose that it has been moved northward, or that the proper climate has left it. We have observed that moist, or water-soaked ground, has influence, as well as climate, to deprive the alburnum vessels sooner of their living functions, inducing that torpor of tubes, or semi-vital condition, in which they only serve to support the more active parts, and constitute what is called Mature Timber.