OF IRON BEAMS. 453 



I. EXPERIMENT. 



Beam with equal rib at top and bottom. 

 Dist. between supports, 4rt. Gins. Depth of beam, 5|iD8. 



Dimensions of cross section, at place of Fractore, 

 io inches and parts. 



Area of top rib = 1.75 x .42 = .735 



Area of bottom rib = 1.77 x .39 = .690 



Thickness of vertical) 



' = .29. 



part, between the ribs,) 



Area of above section = 2.82 inches. 



Weight of Casting = 36J lbs. 

 Breaking weight 66781bs. = 59 cwt. 70 lbs. 



The form of fracture is represented by the 

 line i « r, where / r = .6, and bn zz 2.5, the 

 figure being a side view of the beam. 



To find the strength per inch of cross section, 

 we have, dividing the breaking weight by the area, 

 j-g^ = 2368 lbs. per inch. This quantity in each 



♦ All the sections in these experiments are laid down of \ 

 their real lineal dimensions in order to afford ocular comparison. 



