44 MECHANICS. 



rods of equal size, and applying weights to their lower 

 extremities sufficient to break them, by drawing them 

 asunder. The amount of weight shows their relative de- 

 grees of strength. The following table gives the weights 

 required to break the different substances, each being 

 formed into a rod one quarter of an inch square : 



Woods. 



Ash, toughest 1000 lbs. 



Beech 718 " 



Box 1250 " 



Cedar ' 712 " 



Chestnut 656 " 



Elm 837 " 



Locust 1280 " 



Maple 656 " 



Oak, white. 718 " 



Pine, white 550 " 



" pitch 750 " 



Poplar 437 " 



Walnut 487 " 



Metals. 



Steel, best 9370 lbs. 



" soft 7500 " 



Iron, wire 6440 " 



" best bar 4690 " 



" common bar 3750 " 



" inferior bar 1880 " 



" cast 1150 to 3100 " 



Copper, wire 3800 " 



cast 2030 " 



Brass 2800 " 



Platina wire 3300 " 



Silver, cast 2500 " 



Gold, east 1250 " 



Tin 310 " 



Zinc, cast 160 " 



" sheet 1000 " 



Lead, cast • 55 " 



" milled 207 " 



