STRENGTH OF MATERIALS. 



271 



SOLUTION. 64 x 6 2 x 32 =24576 -=-6 =4129 -fibs. Ans. 

 EXAMPLE 2d. What weight will a cast iron bar 2 inches 

 square and 60 inches between the supports carry ? 



SOLUTION. 400 x 2 a x 8=12800^-5 feet =2560 Ibs. Ans. 



TABLE, showing the resistance of materials to crushing. 



Designation. 



WOODS. In lbs . 



Ash 8,6*3 



Beech, well seasoned, 19,363 



Birch, " " 11,663 



( 'edar, 5,863 



Elder, 9.973 



Elm, well seasoned, 10.331 



Fir. (spruce,) 6 819 



Mahogany, 8.198 



Oak 5,982 



Pine, pitch 6.790 



' yellow, 5445 



Poplar, 5.124 



Sycamore, highly seasoned, 12, 101 



Walnut, 7,227 



Willow, 6,128 



METALS. 



Brass, yellow 10.304 



Iron, cast, 98,000 



" har 4' i.OOO 



" boilerplate 32,000 



MINERALS. 



Brick, common, 800 



" fire, 1,700 



Brickwork, 612 



Chalk 334 



Granite 11,000 



Crushing weight per square inch. 



In tons of 2 00 lbs 

 4.3 

 9.6 

 5.8 

 2.9 

 4.9 

 5.1 

 3.4 

 4.09 

 2.9 

 3.3 

 2.7 

 2.5 

 6. 

 3.6 

 3.06 



5.15 

 49. 

 20. 

 16. 



0.40 



C.85 

 0.306 

 0.16 

 5.50 



STRENGTH OF ICE. 



Ice 2 inches thick will bear men on foot. 

 " 4 " horseback. 



