STRENGTH TESTS OF STRUCTURAL TIMBERS. 
MOISTURE DETERMINATIONS. 
Moisture determinations on the untreated wood were made by 
taking either borings or disks from the tested pieces, weighing them, 
and then drying them to constant weight. The difference between 
the original weight and the dry weight divided by the dry weight 
times 100 is taken as the per cent of moisture at the time of test. 
Disks taken from the untreated stringers were cut into a number of 
pieces and the moisture separately determined for each in order to 
find the distribution of moisture throughout the cross section. The 
method of dividing the disks is shown in figure 2. The moisture 
determinations made on treated specimens were handled by dis- 
tilling the treated shavings cut from the test pieces with water- 
saturated xylol. For such determinations 
a definite quantity of treated borings was 
taken. In all cases a corresponding volume 
of untreated shavings was obtained, and 
the dry weight of this sample determined 
as a basis for computing the moisture con- 
tent of the treated sample. All test pieces 
were weighed and measured, the number 
of rings counted on a radial line, and the <■ 
per cent of summerwood and sap deter- 
mined. 1 Sketches were made and photo- 
graphs taken, showing the size and loca- 
tion of knots, checks, and shakes. 
TESTS ON SMALL STICKS. 
£ a 
tA 
Fig. 2.— Moisture distribution disk 
for 8-inch by 16-inch stringer. 
After failure occurred in the stringers, 
small pieces 2 inches by 2 inches in section 
and 3 feet long were cut from the unbroken 
portions. These small pieces were selected 
so as to be free from defects and with straight grain. Their location 
in a cross section of the stringer was noted, so that data could be 
secured on the relative strength of the inner and outer portions. The 
tests of small pieces included bending tests on specimens 2 by 2 by 30 
inches, compression tests in which specimens 2 by 2 by 8 inches were 
crushed endwise parallel with the grain, compression tests at right 
angles to the grain, and shearing tests in which a projecting portion 
of a small block was sheared off parallel to the grain while the main 
portion of the block was held firm. 
Determinations of summerwood and sap were omitted for some of the Douglas fir. 
