Note 9 — Chapter IV · EXTRACTION OF OBELISK FROM QUARRY.
Reading edition
The check the stress in the levers. Referring to figure 6, (Stress) (Section modulus) = Sum of moments on one side of fulchrum, i. e. (s × .0982 × (25)3) = (1170 × 2240 × 216)/(30 × 21) = 586 pounds per square inch, which is well within the powers of any wood.