Note 51 — PART IV. NOTICES OF AUTHORS RELATIVE TO TIMBER. (continued 2)

We particularize the oak, cork-tree of arid warm Spain, and much of the timber of New Holland. Owing to the hot parching air in the latter place, the epidermis becomes dried to such a degree, that contracting by the drought, and bursting by the swelling of the enveloped stem, it peels off like the old skin of a serpent, and is often seen hanging upon the tree in large shreds like tattered garments. In several kinds of trees, we have counted regular annual rings of desiccated bark; in some kinds this appeared a growth or deposition, in others, mere parched exuviæ. Trees attain some age before the exuviæ commence; the deposit begins the first season, even in sheltered situations. The cork-tree, and the small-leaved elm, shew the greatest annual deposit of dry bark. The former does, and the latter is said to belong to warm arid countries; both form a better nonconductor of heat than any other dry bark we are acquainted with—infinitely better than the bark exuviæ of trees which approach the polar regions.