After these rather lengthy references to facts, we must allude to a circumstance which we are astonished has not been attended to by Mr Withers, and his gentlemen correspondents connected with His Majesty’s docks,—the not taking into account the place of the tree whence the portion of wood for experimenting the strength had been taken, and also how the annual layers stood, whether horizontal or on edge, or around a centre, when the weight was applied. The experienced and accurately practical Mr Withers presents two specimens of oak, the one of faster and the other of slower growth, to Professor Barlow, of Woolwich Royal Academy, and the strength of these specimens is tested and reported upon, without once alluding to what we have mentioned above. Now, if this has not been attended to, the experiment may be considered a test of something else than of the timber. How much the strength is affected by the place of the tree, any person may satisfy himself by proving one piece of timber taken from near the root, another half way up the tree, and a third near the top: he will find that in a tall tree the comparative {212} strength will sometimes vary as much as 3, 2, 1; that is, a beam, say 2 inches square, and 4 feet long, taken from near the root, when horizontally placed, and resting only at each end, will support three times as much as a like beam in like position from near the top of the tree, although both are equally clear of knots or cross section of grain. This is particularly manifest in large fast-grown silver fir and old ash, and the difference is always greatest in old trees. He will also find that the position of the beam, in respect to the layers being circular round the heart, flat, on edge, or at an angle, has considerable influence, and, should he inquire farther, will perhaps notice, that the timber from different sides of the tree is not always alike strong; that one specimen of timber will be superior to another, both being moist, and inferior to it when both are dry, and that also, as in No. 1, the tree at the same height on the same side, will contain timber differing in strength fully one half, and not always diminishing in strength from the heart outwards, even in hard wood. We are well pleased with one gentleman of the Navy Dock-yard, who naively admits, that he is incompetent to decide on these subjects, having been altogether devoted to the mathematical, in estimating the strain and resistance timber suffers under {213} different combinations. Now we like this division of labour.