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TO DETERMINE THE STRENGTH OF THE BRIDGE OVERTHE STRAIT OF MENAI. — THE ROADWAY SUS-PENDED FROM IRON CABLES, UPON THE SUPPOSITIONTHAT THE WHOLE FORMS A CATENARY.
Let x—31 feet, the absciss. * Fig. 1-
y = 280 feet, the ordinate. #
Then z = 283.233, the length of the cable between apoint of suspension and the apex, by cal-culation.
c = 1065.57 the constant force at the apex of thecurve.
p == 14° 53* the angle between the ordinate andthe tangent at the point of suspension.
t n 1102.64 the tension of the cable at the samepoint.
g = 649 lbs. avoirdupois, the weight of the cableper foot; for there are to be 16 cables, thearea of whose collected sections (12 squareinches each) amount to 192 square inches:as 144 : 7788 oz. (spec.grav.) :: 192 : 649lbs. -
to — 587.5 tons, being half the weight to be sus-pended; arising as follows :
Tons.
Weight of the cable, 2a X 649 lbs.= 164