of wood--the relation of wood material to stresses and strains.
Much of the subject-matter is merely elementary mechanics of
materials in general, though written with reference to wood in
particular. Numerous tables are included, showing the various
strength values of many of the more important American woods.

Part II deals with the factors affecting the mechanical
properties of wood. This is a subject of interest to all who are
concerned in the rational use of wood, and to the forester it
also, by retrospection, suggests ways and means of regulating
his forest product through control of the conditions of
production. Attempt has been made, in the light of all data at
hand, to answer many moot questions, such as the effect on the
quality of wood of rate of growth, season of cutting, heartwood
and sapwood, locality of growth, weight, water content,
steaming, and defects.

Part III describes methods of timber testing. They are for the
most part those followed by the U.S. Forest Service. In schools
equipped with the necessary machinery the instructions will
serve to direct the tests; in others a study of the text with
reference to the illustrations should give an adequate
conception of the methods employed in this most important line
of research.

The appendix contains a copy of the working plan followed by the
U.S. Forest Service in the extensive investigations covering the
mechanical properties of the woods grown in the United States.
It contains many valuable suggestions for the independent
investigator. In addition four tables of strength values for