156. To find the greatest weight that may be placed on a square pillar of 30 diameters and upwards.

Rule XIV. - Multiply the fourth power of the side of the pillar in inches by the value of e (Table XXIII), and divide by the square of the length in feet, and the quotient will be the weight required in pounds.

Example. - Required the weight in pounds that may be sustained by a pillar of Dantzic oak 10 feet long and 4 inches square. The value of e (Table XXIII.) being 2410,

2410 x4 4/102 = 2410x256/100 = 6169.6 lbs., the weight required.

157. For cylindrical pillars proceed as in Rule XIV., but divide by 1.7 times the square of the length.

* 'Phil. Trans.,'1840.

† Ibid., 1857.

158. When the pillar is rectangular -

Rule XV. - Multiply the greater side by the cube of the least both in inches, and divide by the square of the length in feet, and the quotient multiplied by the value of e (Table XXIII.) will give the weight that the pillar will support in pounds.

Example. - What weight will a pillar of Red Pine 12 feet long support, the scantling being 6 inches by 4 inches, and the value of e (Table XXIII.) being 2219?

2219x6x43 /122 = 2219x6x64/144 = 5917 3lbs., the weight required.