= elastic limit.

The areas of the triangles 0( EL)A and 0( EL)B represent the elastic resilience of the dry and green beams, respectively.] There are three kinds of internal stresses, namely, (1) ~tensile~, (2) ~compressive~, and (3) ~shearing~.

When external forces act upon a bar in a direction away from its ends or a direct pull, the stress is a tensile stress; when toward the ends or a direct push, compressive stress.

In the first instance the strain is an _elongation_; in the second a _shortening_.
Whenever the forces tend to cause one portion of the material to slide upon another adjacent to it the action is called a _shear_.

The action is that of an ordinary pair of shears.