RULE FOR FINDING PRESSURE OR STRAIN ON BOLTS.

The absolute stress or strain on a flat surface of a steam boiler,

which is carried by the stays, can be easily determined by a simple

rule:

Choose 3 stays as A B C in Fig. 46, measure from A to B _in inches_,

and from A to C. Multiply these two numbers together and the result

is the number of square inches of surface depending upon one bolt for

supporting strength.