TABLE of the Areas of the Segments of Circles, the Diameter of which is Unity, and supposed to be divided into 1000 Parts. See Areas, p. 53.

TABLE of the Lengths of Circular Arcs, whose Base is Unity.

TABLE for ascertaining Heights and Distances by the Box-Sextant.

TABLE of the relative Proportions of the Circle, its Equal and Inscribed Squares.

TABLE XX.

TABLE showing the Weight of a Lineal Foot of Square and Round Bar-Iron.

TABLE showing the Weight in Pounds of a Lineal Foot of Flat Bar-Iron closely

hammered.

Weight of ordinary angle iron in lbs. per lineal foot:

Breadth in inches....... 1 1 1 2 2 2 2 3
Weight, per foot, in lbs... 1.5 2.45 3.64 4.09 5.8 7.11 8.2 9.18 11.12 13.12

31

3

TABLE XXII.

WEIGHT of Hexagon Head and Nut, Square Head and Nut, Rose Head and Nut; will equal that of Rod-Iron of the same Diameter as the Bolts, and of the following Lengths.

Thickness of nut = diameter of bolt.

head= diameter of bolt.

Whitworth's pitch of thread: inclination of sides of thread is an angle of 55° for all diameters, rounded top and bottom.

Every yard run 1 inch square 10 lbs.

وو

foot super. 1 inch thick = 40 lbs.

Cast-iron is 5 per cent., or 100 lbs. weight, less than wrought-iron.

5 per cent. for rivets on the whole amount of tonnage.

A cube foot of wrought-iron

= 480 lbs.

TABLE XXIII.

TABLE for calculating Girders on the Skew.

Rule: Multiply the width of the Girder on the Square by the Numbers opposite the

given Angle.