The modulus of rupture in bending lies between the first power and the square of the density.

This, of course, is true only in case the greater weight is due to increase in the amount of wood substance.

A wood heavy with resin or other infiltrated substance is not necessarily stronger than a similar specimen free from such materials.

If differences in weight are due to degree of seasoning, in other words, to the relative amounts of water contained, the rules given above will of course not hold, since strength increases with dryness.

But of given specimens of pine or of oak, for example, in the green condition, the comparative strength may be inferred from the weight.