which would require only thirteen and one half inches for compression, or a piece 4 × 3½. But is this enough for flexure?
On page [124] the load which may be safely borne, by a rectangular post of wood, is shown by the formula
W = 2240bd3
L2.
Substituting for b and d, the dimensions 4 × 4, we have
W = 2240 × 4 × 43
182, or 573,440
324, = 1,770,
which is evidently too small.
Placing 6 × 7, for b × d, we have
W = 2240 × 6 × 73
182 = 14,227;
exceeding by a small amount the requirement.
