is practically certain that it will produce complete failure
or 6-inch deflection in the case of all specimens of a species.
For all other species, a 100-pound hammer will be used.

In all cases drum records will be made until first failure. Also
the height of drop causing complete failure or 6-inch deflection
will be noted.

_Compression parallel to grain_: This test will be on specimens
2" X 2" X 8" in size. On 20 per cent of these tests
load-compression curves for a 6-inch centrally located gauge
length will be taken. Readings will be continued until the
elastic limit is well passed. The other 80 per cent of the tests
will be made for the purpose of obtaining the maximum load only.

_Compression perpendicular to grain_: This test will be on
specimens 2" X 2" X 6" in size. The bearing plates will be 2
inches wide. The rate of descent of the moving head will be
0.024 inch per minute. The load-compression curve will be
plotted to 0.1 inch compression and the test will then be
discontinued.

_Hardness_: The tool shown in Fig. 43 (an adaptation of the
apparatus used by the German investigator, Janka) will be used.
The rate of descent of the moving head will be 0.25 inch per
minute. When the penetration has progressed to the point at
which the plate "_a_" becomes tight, due to being pressed
against the wood, the load will be read and recorded.

Two penetrations will be made on a tangential surface, two on a
radial, and one on each end of each specimen tested. The choice
between the two radial and between the two tangential surfaces
and the distribution of the penetrations over the surfaces will
be so made as to get a fair average of heart and sap, slow and
fast growth, and spring and summer wood. Specimens will be 2" X
2" X 6".

_Shear_: The tests will be made with a tool slightly modified
from that shown in Circular 38. The speed of descent of head
will be 0.015 inch per minute. The only measurements to be made
are those of the shearing area. The offset will be 1/8 inch.
Specimens will be 2" X 2" X 2-1/2" in size. (For definition of
offset and form of test specimen, see Fig. 38.)

_Cleavage_: The cleavage tests will be made on specimens of the
form and size shown in Fig. 45. The apparatus will be as shown
in Fig. 44. The maximum load only will be taken and the result
expressed in pounds per inch of width. The speed of the moving
head will be 0.25 inch per minute.

_Moisture Determinations_

Moisture deter