304 
TIMBEE 
Barlow, Laslett, and many others in this country, we owe 
a great deal, since it was from the tests on small pieces of 
timber made in a primitive manner, but with the best 
means at their disposal and before the days of large testing 
machines, that men had to deduce the scantlings required 
for constructional work ; now, however, when better means 
are available, endeavours should be made to produce results 
which can be depended upon with something akin to the 
reliance placed upon tests of steel, although there are 
difficulties in connection with the testing of timber which 
do not occur in the testing of steel. 
The amount of moisture in timber considerably affects 
the result of tests, probably to a greater extent than any- 
thing else. The drier the timber, the higher the results 
obtained ; in other words, seasoned tiniher is stronger than 
greeit timber, and that to a very considerable extent, as will be 
shown ; but in general it will be safer in making calculations 
for strength of constructional timber to make use of the 
tests for moderately seasoned wood, as it is not often that 
highly seasoned timber is used ; it too often has to season 
in the work. 
It is, therefore, useless making comparisons between tests 
of timber unless we compare their conditions of moisture. 
It takes a very long time by air seasoning to thoroughly 
dry timber of large sizes. Two pieces of pitch pine 16 ft. 
by 12 inches by 12 inches and 16 ft. by 16 inches by 8 inches, 
after air seasoning for two years, showed that whilst in the 
outer portion of the wood there was only 17 per cent, of 
moisture, the inner portion still contained 25 per cent. ; ~ 
1 A number of tests on largo-sized columns and beams of oak were 
made by M. P. S. Grirard in France so far back as 1798, but these tests 
appear to have been lost sight of, and others of less value used. (See 
Barlow's Strength of Materials, 1837.) 
2 Bulletin No. 70, United States Dept. of Agriculture, p. 123. 
