492 The Philippine Journal of Science 1921 
sion parallel to grain; for flooring and railroad ties the desir- 
able properties are hardness and compression perpendicular to 
grain. 
TESTING METHOD 
A complete description of the testing method employed is 
given by the United States Forest Service.” A brief description 
of the different tests will aid the reader in attaching the proper 
significance to the results presented. The testing machines were 
calibrated before starting the tests. The formule used in cal- 
culating the different results contained in the tables will be found 
in the appendix. 
BENDING TESTS 
STRINGERS AND HEAVY JOISTS 
Fig. 1 shows the apparatus used for bending tests on large 
beams. The testing machine is provided with an extension 
weighing platform. The beam is placed on two knife-edge sup- 
ports, AA, which rest on this platform. The load is applied at 
Ul 
a 
Fic. 1. Apparatus used for bending tests on large beams. 
two points, BB, one-third as far apart as the distance between the 
knife-edge supports. As the head of the screw press, C, moves 
down, the straining beam, D, bears with increasing force on 
the specimen under test. As the load increases the beam deflects. 
A fine wire, EE, kept taut by a weight, is strung between two 
small nails driven midway between the top and bottom faces of 
the beam vertically above the knife-edge supports. This wire 
crosses the face of a scale, F, fastened to the beam midway be- 
"Instructions to Engineers of Timber Tests, Circular (revised) U. S. 
Forest Service 38 (1909). 
