Memel fir, 0, 43, 0 Red Canadian pine, 0, 100, 0 Yellow Canadian pine, 38, 44, 0 The process of maturing in several did not proceed regularly, some of the rings being reddened on one side and remaining white on the other: this did not seem to be influenced by position to south or north. In the larch, particularly in those trees {125} where the rot is incipient, this maturing is very irregular, in the view of the cross section dashing out into angles and irregularities, and being darker red than in the healthy plants: in those where rot had made considerable progress, the red-wood was within a circle or two of the bark. This approach of red-wood to the outside is so regularly connected with rot, that we needed no other indication of the roots being unfit for knees, and therefore not worth grubbing, than merely a slight notch by two cuts of a hatchet. Those kinds of timber whose matured wood assumes a brown or reddish colour, are generally much less susceptible of change, either by simple putrefaction or by attack of fungi, or gnawing of insects, than those whose matured wood remains of a whitish colour. In many of the latter, there does not even appear to be any particular change of constitution, or greater capability of resisting corruption or insects, between the alburnum and mature wood, although the difference between the two is generally perceptible when the cross section is drying, and immediate, as in the brown or red; there being no gradual change or softening in either between the mature and immature. Although the change in those which become brown and red does not much affect {126} the hardness or strength of the timber (mature and immature being nearly equal in these when dried before corruption injures the latter), yet it materially influences its nature or quality. We have taken down Laburnum trees in the round natural form from the roofing of an old building, from which nearly the whole yellow or sap-wood was eaten away by insects, although they had not made the least impression upon the brown[28]. {127}