268 



STRENGTH OF MATERIALS. 



HEMPEN 'CORDS. 



Hempen cords when twisted will support the following 

 weights to the square inch of their section : 



Diameter. Lbs. 



to 1 inch 8746 



1 to 3 inches . . . 6800 



Diameter. Lbs. 



3 to 5 inches 5345 



5 to 7 inches. . . 4860 



NOTE. A square inch of hemp fibres will support a 

 weight of 9200 Ibs. 



The ma&imum strength of a good hemp rope is 6400 Ibs. 

 to the square inch. Impractical value not more than one- 

 half this strain. Before breaking it stretches from % to 1, 

 and its diameter diminishes from ^ to ^-. 



The strength of manilla is about that of hemp. White 

 ropes are ^ more durable. 



LATERAL OR TRANSVERSE STRENGTH. 



TABLE, showing the transverse strength of timber, 1 foot 

 long and 1 inch square : Weight suspended from one end. 



