APPENDIX. 
METHODS. 
TESTING. 
The 6-foot props were tested in compression parallel to the grain 
at a speed of 0.119 inch per minute. A bearing block was used 
between the prop and the base of the machine. The compression of 
the prop, as indicated by the movement of the head of the testing 
machine, was read to thousandths of an inch by means of an Olsen 
deflectometer. Figure 6 shows a prop in the testing machine after 
failure. 
The 8-foot caps were tested on a 7-foot span with third-point load- 
ing. The tests were made on a 200,000-pound Riehle testing machine 
at a speed of 0.231 inch per minute. The ends were supported by 
curved cast-iron bearing blocks and the load applied at two points 
(one-third the length of the span from either end) through curved 
wooden blocks. Deflections were read at the center of the beam to 
hundredths of an inch by observing on a taut string the movement 
of a polished metal scale attached to the timber. The method of 
loading is shown in figure 7, all parts of the testing machine being 
omitted except the weighing platform. 
The 16-foot lodgepole pine beams were tested on a 15-foot span 
with third-point loading. The arrangement was similar to that 
used for the caps. 
MOISTURE DETERMINATIONS. 
A 1-inch section was cut from near the point of failure of each 
piece tested. This was immediately weighed and later dried to con- 
stant weight at the temperature of boiling water. The loss in weight 
divided by the dry weight, expressed in per cent, is the moisture 
content of the piece. 
GENERAL OBSERVATIONS. 
The length, weight, and diameters of the timbers were obtained 
j ust before testing. The rings per inch and the proportion of sap wood 
and of summerwood were obtained from a section cut near the point 
of failure. The values for the amount of summerwood are approxi- 
mate, as the summerwood bands were not distinctly marked in many 
of the pieces. 
COMPUTATIONS. 
The load and deflection at the elastic limit were obtained from the 
load-deflection curve, and at maximum load by direct observation, 
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