14.) In bending tests on wet beams, first failure occurs by compression on top of the beam, gradually extending downward toward the neutral axis.

Finally the beam ruptures at the bottom.

In the case of very dry beams the failure is usually by splitting or tension on the under side (see Fig.

17.), without compression on the upper, and is often sudden and without warning, and even while the load is still increasing.

The effect varies somewhat with different species, chestnut, for example, becoming more brittle upon drying than do ash, hemlock, and longleaf pine.