EXAMPLES.-What is the weight of a bar of iron 54 inches in breadth by inches

thick?

In column 4, page 250, find 54, and below it, in column 5, ; and opposite to that is 13.307, which is 13 lbs. and 30% of a lb.

1000

For parts of a lb. and of a foot, operate precisely similar to the rule laid down for table, page 247.

WEIGHTS OF A SQUARE FOOT OF IRON IN AVOIRDUPOIS POUnds.

Number 1 is, number 4 is, and number 11 is of an inch.

CAST IRON.

To ascertain the weight of a cast iron Bar or Rod, find the weight of a wrought iron bar or rod of the same dimensions in the preceding tables, and from the weight deduct the 4th part; or say,

As 486.65: 450.55: : the weight in the table: to the weight required. Thus,

What is the weight of a piece of cast iron 4×3×12 inches?

In table, page 250, the weight of a piece of wrought iron of these dimensions is 50.692 lbs.

486.65:450.55:: 50.692: 46.93 lbs.

Or, by an easier mode, though not so minutely correct,

As 281 260 :: 50.692: 46.90 lbs.

To find the Weight of a piece of CAST or WROUGHT IRON of any size or shape.

By the rules given in Mensuration of Solids (see page 81), ascertain the number of cubic inches in the piece, multiply by the weight of a cubic inch, and the product will be the weight in pounds.

EXAMPLES.

What is the weight of a block of wrought iron 10 inches square by 15 inches in length?

What is the weight of a cast iron ball 15 inches in diameter ?