We see, by every day’s experience, that the human skeleton moulders to dust in a very few years, when buried in mould: so it does even in vaults, where the coffins are kept dry. In the first case, the moisture and salts of the earth divide and dissolve the texture of the bones; in the latter, those of the air, which gradually insinuate themselves into them, and at length destroy them. How long a skeleton whose bones are well dried and prepared, being totally deprived of its medullary substance, will last, as we now order them for anatomical purposes, we cannot say: but it may be reasonably conjectured, that they will undergo the fate of the softer kinds of wood, such as beech, which grows rotten in no great number of years; because their internal substance is spungy and cellular, and their crust is very thin, except about the middle of the bones of the arm and thigh, I mean the humerus and fœmur. The same destruction would happen, if bodies were deposited in a sandy soil; because water finds its way either by dripping downwards, or by springs underneath. But human skeletons have been found intire within a rock, where neither moisture nor air could get at them. Mr. Minors, an eminent Surgeon and Anatomist of the Middlesex-hospital, when he was in the Army, at Gibraltar, saw an intire skeleton, standing upright, in a dry rock, part of which had been blown up with gunpowder, in carrying on some works in the fortifications, which left the skeleton quite exposed. Indeed, the bones of Elephants have been found in Shepey-Island, but much destroyed, several of which I have in my Collection; an account of which we have in the last volume but one[206] of our Transactions; their size and substance being so considerable, as to resist for a long time that decay which those of the human could not withstand. To these we may add the horns of large animals, as the elk, and others, which have been found in bogs, preserved as the bog-oak, _&c._ mentioned. TEETH _and_ PALATES _of_ FISHES _and other Animals_. These are of so hard and firm a texture, as to suffer no great change, wheresoever found; for we see, that no erosion appears in them, their enamel and its polish being intirely preserved; yet sometimes their roots will be found changed, especially in the yellow ones, having no enamel to guard them in their roots. _Parts of_ VEGETABLES. The leaves of plants, whose fibres are firm and dry, will endure for a long time; but those of a succulent nature never can, as they putrify very soon. We see the leaves of ferns of several kinds, polypodium, tricomanes, and other capillary plants, with nodules of stone formed about them; flags, reeds, rushes, equisetum, and many such, of a firm texture, are found in slate and stone; and even the iuli of trees are said to have been found fossil as well as their leaves. SEEDS _and_ FRUITS.