In this paper I propose to bring before you a broad outline of our knowledge of the subject, not from the point of view of a botanist, but purely from the point of view of an engineer.

Although in ancient, and in fact during all time, timber has been extensively used for constructional purposes, our knowledge of it is comparatively small, whilst the subject itself is very extensive.

The reason for these facts is not hard to find. Unfortunately the physicist has not in general had to deal with timber in the progress of physical research, as he has with metals; and the questions which concern the engineer are not in general those with which the botanist deals.

There has been comparatively little incentive for engineers to do much work on timber, as before the advent of the aeroplane its application was limited to unimportant parts, except in America and the Colonies, where the cost of metal parts is high. A considerable amount of information has in recent years been published by the American Government Forestry Department; the Government of New South Wales, Australia, have also published a considerable amount of data on Australian timbers.