EXAMPLES TO THE FIRST SEEIES. 
xxiii 
Minimum, Mean, and Maximum Strength. 
By Table X. p. 146, the mean results of 71 Experiments upon 
various species of timber are, — 
Minimum strength, '897. 
Mean strength, 1-000. 
Maximum strength, 1-077. 
If the greatest variation in the strength of sound timber of the same 
species be 10 per cent, below, and 8 per cent, above, the mean strength, 
the depth and breadth for those strengths are given by Cols. II. and III. 
p. 2. 
Thus, if 10X3 be the scantling for the mean strength, 
then 10-54X3 or 10X3-33 are the scantlings for the minimum 
strength ; 
and 9-62X3 or 10X2-78 are the scantlings for the maximum 
strength. 
Breadth, Depth, and Weight, to have the same deflection. 
By the Second Series of Tables, p. 70, Red Pine 10 feet long 10 in. 
by 3 in., with 30 cwts. uniformly loaded, deflects -164 of an inch. 
Example to Col. IV. 
Relative elasticity: Red Pine 1-000; Riga Fir 1-6033. 
•164 X 1-6033 = -263 of an inch. 
Riga Fir 10 feet long 10 X3, with 30 cwts. uniformly loaded, deflects 
•263 of an inch. 
The weight and depth being the same, the breadth varies as the 
elasticity. 
3 X 1-6033 = 4-8099 inches. 
Riga Fir 10 feet long 10 X4-81, with 30 cwts. uniformly loaded, deflects 
-164 of an inch. 
Example to Col. V. 
Depth to have the same deflection: Red Pine 1-000; Riga Fir 1-170. 
10 X 1-170 =11-70 inches. 
Riga Fir 10 feet long 1 1-70 X3, with 30 cwts. uniformly loaded, deflects 
• 1 64 of an inch. 
Example to Col. VI. 
Weight to have the same deflection; Red Pine 1-000; Riga Fir -623. 
30 X -623 = 18-69 cwts. 
Riga Fir 10 feet long 10 X3, with 18-69 cwts. uniformly loaded, deflects 
•164 of an iuch. 
