446 



ERECTION OF STRUCTURAL STEEL. 



CHAP. XIV. 



over the centre of the knot, strand b laid over a, and c over b, wKen the end of c is passed through 

 the bight of a, as shown in 28. Haul all the strands taut, as shown in 29." 

 The efficiency of a knot will vary from 45 to 75 per cent. 



TABLE IV. 



PLOUGH STEEL HOISTING ROPE. WEIGHT, ULTIMATE STRENGTH AND WORKING LOADS OF WIRE 

 ROPE COMPOSED OF 6 STRANDS AND A HEMP CENTER, 19 WIRES TO THE STRAND. 



TABLE V. 

 DATA ON WOODEN BLOCKS FOR MANILA ROPE. AMERICAN BRIDGE COMPANY. 



Wire Rope. Wire hoisting rope is now used for heavy hoisting and in all cases where prac- 

 ticable. Wire rope is much more reliable, gives much greater service, and is much more eco- 



