ON IRON BEAMS. 417 



Expeviinenl Third — Arm 3 feet 9 inches. 



Breaking weight = 663 lbs. 

 Do, reduced to arm of 4 feet, = 621 lbs. 



Ratio of flanges, 11 to 21. 

 It broke two inches behind the shoulder. 



Experiment Fourth — Arm 3 feet 2 inches. 



Breaking weight = 9041bs. 



Do. reduced to arm of 4 feet, =715 lbs., 



or 721 lbs., including weight of arm. 



Ratio of flanges, 12 to 19. 



Expeiimeiit Fifth — Arm 2 feet 94 inches. 



It broke at shoulder, with 932 lbs. 



Breaking weight, reduced to arm of 4ft., = 650 lbs. 



Do. including weight of arm = 655 lbs. 



Ratio of flanges, 13 to 18. 



From the above, we may deduce the following 

 approximate ratios of the flanges, and their 

 breaking weights. 



Ratio of flanges. Breaking weights 



1 to 4} 665 lbs. 



1 to 3| 579 „ 



I to 2 621 „ 



1 to U 721 „ 



1 to 1} Q,bb ,, 



I made several other experiments, in the 



