ON THE STRENGTH OF PILLARS. 
429 
value of d (Art. 65.) might have been assumed somewhat higher. The experimental 
results of Girard from pillars of oak * were calculated, but they agree so little among 
themselves, that the results of those which were consistent with one another are not 
given. The reason of the irregularity was attempted to be explained in the early part 
of this paper (Art. 17.)' 
Other computations, upon the shortest pillars in Table XIII., agree moderately 
well with the results of experiment. 
Crushing Strength of Timber. 
67- To facilitate computations, as to the strength of short pillars of different 
kinds of wood in the manner above, or otherwise, I shall insert below, from my own 
experiments, the crushing strength per square inch of some of the descriptions in 
frequent use, the force being applied in the direction of the fibre. 
Description of Wood. 
Strength per square inch in lbs. 
Alder 
6831 to 6960 
Ash 
8683 to 9363 
Baywood 
7518 to 7518 
Beech 
7733 to 9363 
American birch 
11663 
English birch 
3297 to 6402 
Cedar 
5674 to 5863 
Crab 
6499 to 7148 
Red deal 
5748 to 6586 
White deal 
6781 to 7293 
Elder 
7451 to 9973 
Elm 
10331 
Fir (spruce) 
6499 to 6819 
Hornbeam 
4533 to 7289 
Mahogany 
8198 to 8198 
Oak (Quebec) 
4231 to 5982 
Oak (English) 
6484 10058 
Oak (Dantzic, very dry) 
7731 
Pine (pitch) 
6790 to 6790 
Pine (yellow, full of turpentine) .... 
5375 to 5445 
Pine (red) 
5395 to 7518 
Poplar 
3107 to 5124 
Plum (wet) 
3654 
Plum (dry) 
8241 to 10493 
Sycamore 
7082 
Teak 
12101 
Larch (fallen two months) 
3201 to 5568 
Walnut 
6063 to 7227 
Willow 
2898 to 6128 
The results in the first column were in each case a mean from about three experi- 
ments upon cylinders of wood turned to be one inch diameter, and two inches 
long, flat at the ends. The wood was moderately dry, being such as is employed in 
making models for castings. The second column gives the mean strength, as before, 
from similar specimens, after being turned and kept drying in a warm place two 
* Traite Analytique de la Resistance des Solides. 
