x.] BRITISH OAK. 65 
quired to crush them was, severally, 7,640 lbs., 7,224 Ibs., 
and 7,058 lbs., per square inch of base, which, if com- 
pared with 7,978 lbs. on the one-inch cube of the same 
seasoned wood, shows an apparent diminution of strength 
in each of the next larger sizes; the average force 
required to crush the complete parcel of four sets of 
cubes being 7,475 lbs. The average strength of the 
unseasoned pieces of the same dimensions only 4,915 Ibs. 
to the square inch of base. 
In the experiments (Table XVII.) on a set of fifteen 
specimens, each 2 X 2 inches, and severally varying only 
1 inch in length from 1 to 12 inches, and then by 6 
inches, until a length of 30 inches was obtained, it was 
found that the piece 5 inches in length bore the maxi- 
mum pressure of 8,820 Ibs., or 3°937 tons on the square 
inch, the resisting power of each of the others being less, 
while the piece of 24 inches was crushed by about two- 
thirds the strain of that of 5 inches in length. 
From this it would appear that the proper proportion 
of sectional area to length for this description of timber 
is as about 4:5; or, in other words, the superficial area of 
the base in inches should not be less than four-fifths 
the length of the pillar or column in inches. 
Thus, if it were required to ascertain the scantling 
for an Oak pillar, 144 inches in length, to ensure its 
carrying the maximum of strain, we should have 
Vv “4 = 10°73 inches for the side of that pillar, and 
according to the ascertained strength of our specimen, 
5 inches in length, this would be capable of bearing a 
weight of 453 tons. Even if we observe the rule, recom- 
mended by many authorities, of only loading to one- 
fourth of the calculated strength, we may still consider 
it equal to the strain of 113 tons, while a pillar of Riga 
F 
