142, U.S.F.S.: Tests on vehicle and implement woods.
_Cross-arms_ In tests by the U.S.Forest Service on cross-arms a special apparatus was devised in which the load was distributed along the arm as in actual practice.

The load was applied by rods passing through the pinholes in the arms.

Nuts on these rods pulled down on the wooden bearing-blocks shaped to fit the upper side of the arm.

The lower ends of these rods were attached to a system of equalizing levers, so arranged that the load at each pinhole would be the same.

In all the tests the load was applied vertically by means of the static machine.
See Cir.