The artillerist's manual and British soldier's compendium

by F. A. Griffiths

The square of the diameter of the link, measured in eighths of inches, will give the weight of the chain, per fathom, in pounds.

Example.—What is the weight per fathom of a ¾-inch chain?

¾-inch = 6 8 ; 6² = 36 lb. Weight per fathom.

Or, the weight per foot of the chain, multiplied by 24, will give the weight per fathom of the chain, nearly. A chain cable with a stay across the links will weigh about one-twelfth more than the foregoing examples.

To find the weight that may be safely lifted by a chain.

Divide the square of the diameter of the links, taken in eighths of an inch by 8, and the quotient will give the number of tons that may be lifted by the chain.

Example.—What number of tons will a chain made of ¾-inch iron carry with safety?

¾-inch = 6 8 6² = 36 36 8 = 4½ tons. Weight required.

The safe strain is equal to about 8 tons, per square inch, of the iron of which the chain is made.