90 
Ohio Biological Survey 
plied by the number of pounds per cubic foot gives kilograms per 
cubic decimeter, which is the same as the specific gravity. 
The reciprocal of the weight of a cubic foot of water equals the 
approximate weight per cubic decimeter in kilograms. 
Each piece contained 10.125 cubic inches. 
SUMMARY OF RESULTS. 
In all cases except one, where the weight was the same, the 
pieces were lighter after soaking and drying than before they were 
first placed in water. 
In many cases the samples suddenly absorbed more water after 
they had once nearly or entirely ceased absorption. This may be 
due to a slight increase in temperature or the water penetrating some 
place that it had not previously entered. 
There was a marked difference in the absorption of the two 
pieces of Beech, considerable in the two pieces of Tulip-tree (Yellow 
Poplar), less in the two pieces of Jersey Pine and White Hickory,, 
while the two pieces of Ohio Buckeye and the two pieces of Cotton¬ 
wood are in each case, nearly equal. 
In general the woods having the least absorptive capacity are 
the most durable species. For a given amount of water absorbed the 
more porous woods show a less amount of volumetric increase than 
the less porous sorts. 
The per cent of absorption is correlated with absorptive capacity. 
Average absorptive capacity of sixty-nine (69) samples was eigh¬ 
ty-eight (88) per cent of the original weight of the samples. 
In the first soaking the per cent of absorption was least in the 
Yellow Locust, forty-eight (48), and greatest in the Ohio Buckeye, 
one hundred and eighty-one (181). The average daily absorption 
varied from forty-one hundredths (.41) grams in the Yellow Locust 
to one (1) gram per day in the Ohio Buckeye. The average of all 
was sixty-seven hundredths (.67) grams per day. 
In the second test the average daily absorption was the same as 
in the first in only one case, that of the Cucumber Tree. In four 
cases it was greater, and in all other cases less. The average was 
fifty-five hundredths (.55) of a gram each day. 
The average total absorption of twenty-seven (27) samples of 
the softer woods was ninety-nine (99) grams each, or ninety-four (94) 
per cent of their original weight; of ten (10) medium woods the aver- 
