478 



THE STRENGTH 



Dimensions of cross section in inches. 



Area of top rib=2.33 x .31 =72 

 „ of bottom „ = 6.67 x .66 = 4.4 



Thickness of ^ __ 266 



vertical part ' 



Area of section =: 6.4, or 6-5 ins. 



Weight of beam = 71 lbs. 



This beam broke in the middle by compression 

 with 26084 lbs, or 11 tons 13 cwt,, a wedge 

 separating from its upper side. 



The weights were laid gradually and slowly 

 on, and the beam had borne within a little of 

 its breaking weight a considerable time, perhaps 

 half an hour. 



The form of the fracture and wedge is 

 represented by the figure, shewing a side view 

 of the beam^ where enf is the wedge, ef 



^rv 



= 6.1 inches, <w = 3.9 inches, angle enf at 

 vertex = 82°. 



It is extremely probable, from this fracture, 

 that the neutral point was at w, the vertex of 



