18 



NUMBERS AND MEASURES. 



A best hemp rope 1 inch round will carry about 1000 Ibs. An 

 iron wire rope an inch round will carry a ton, one two inches round 

 will carry 4 tons. A steel wire rope two inches round will carry 

 11 '2 tons. An Italian tarred hemp rope one inch round will carry 

 '3 of a ton, one two inches round will carry 1*44 tons. N.B. The 

 tenacity of ropes does not vary exactly as the squares of their 

 radii. 



(22) RESISTANCE OF SUBSTANCES TO CRUSHING IN TONNES PER 

 SQUARE CENTIMETRE. 



Ash -633 



Box -724 



Ebony 1'34 



Mahogany '576 



Oak -703 



Teak '844 



Aluminium bronze 9*28 



Brass (cast) '724 



Iron (mean, cast) 7*87 



Iron (wrought) 2 '76 



Steel (cast) 18'91 



Basalt .. -843 



Brick (strong red) ...... '077 



Brick (fire) ............... '12 



Chalk 

 Granite (Mt. Sorrel) ... 

 Granite (Argyllshire)... 

 Grauwacke Pcnmaen- 



'023 

 '907 

 "766 



'188 



Limestone (magnesian) -| 



Marble ..................... '387 



Sandstone (Yorkshire). '69 



Syenite (Mt. Sorrel) ... '83 



