OP IRON* BEAMS. 533 



ones, the beam should have a large rib at top, 

 and a small one at bottom, and be formed 

 like that in the conclusion of the last article. 

 But the further consideration of this matter 

 iwould extend too far the limits of this 

 paper ; it would be well, however, if it were 

 subjected to experiment, as that might tend 

 to a reduction in the mass, and inertia, of these 

 beams. 



ULTIMATE DEFLECTION. 



76. Having, in a variety of cases, obtalhed 

 ,the strengths of beams and the laws on which 

 they depend, we will next seek for the ultimate 

 deflection in the different experiments. This 

 may be done without much error, by supposing 

 it proportional to the breaking weight, and 

 comparing it with some other weight, whose 

 deflection was taken; as for instance, the largest 

 in each experiment. 



BEAMS 4 feet 6 inches BETWEEN SUPPORTS, 

 AND 5J inches DEEP. 



In experiment 11, 13706 lbs. bent the beam 

 .62 inch, and 14462 lbs. broke it. 



/. 13706 : 14462 :: .62 : .56 inch = ultimate 

 deflection. 

 In experiment 12, .63 inch = ultimate deflection. 



