2 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 
in which careful records were kept not only of the moisture 
conditions, but of the previous history of the wood from which 
the specimens were prepared. Professor Bauschinger carried 
out at Munich, in 1883 and in 1887, two classical researches 
upon this subject, and the results obtained were published in 
Mittheilungen aus dem Mechanisch-Technischen Laboratorium der 
K. Technischen Hochschule in Miinchen, in 1883 and 1887. 
These original publications should be consulted by anyone 
anxious to learn the exact way in which these experiments 
were conducted, but the substance of the results obtained is 
given in Professor Unwin’s work on the Testing of Materials of 
Construction. 
One of the earliest points in the research was the determina- 
tion of the influence of the moisture present in the sample of 
timber upon its compressive and bending strength. The method 
adopted by Bauschinger for determining the dryness of his 
specimens was as follows :—sawdust, or small chips from the 
actual specimen, was carefully dried in a current of warm air 
kept at a temperature of about 212° F., and maintained for 
about eight hours: the sample of sawdust or chips was weighed 
carefully before subjection to this drying current, and immedi- 
ately afterwards; the difference of weight in the two weighings 
gave, therefore, the amount of moisture present, and therefore 
its percentage in terms of the dry weight of the sample. In 
his later research Bauschinger adopted, in preference to this plan, 
the method of drying the whole tested specimen for a period 
of from two to four days in an oven, where the air temperature 
was maintained at 212° F., as in the previous method, and again 
the difference between the weighings before and after the 
specimen had been placed in the oven gave the total moisture 
present in the entire specimen. This second method is no 
doubt a better plan, because any local differences in the 
moisture present in the specimen are eliminated, but it is a 
little more difficult to ensure uniformity of dryness throughout 
the whole specimen, unless the specimen is kept in the hot- 
air oven for a considerable length of time. 
I may point out here that timber thus artificially dried very 
rapidly reabsorbs moisture from the air, and, in fact, timber 
which has been used and kept in a well-warmed, dry house 
for a long period of time would probably have as much as 
Io per cent. of moisture present in it. It is, therefore, not 
