406 THE STRENGTH 



Weight of beam = 38 lbs. 

 Deflection with 6679 lbs. .37 inches. 

 „ 9495 „ .50 i, 

 „ 9279 „ .62 „ 

 Breaking weight = 9503 lbs. \ y ia/-i 

 It twisted in a serpentine manner before ithtdke. 

 The form of fracture was nearly as in experi- 

 ment 4, but here tr = 1.0, and bn z= 2.5. ; 



Hence strength per square inch of section 

 = II = 3188 lbs. 



This beam is not used alone for comparison 

 with the others, as it was conceived to have been 

 cast, under the pressure of a superior head of 

 metal. Which, with the different mode in 

 which it was cast, may account for its increased 

 strength. 



-»,Ilemark. — In the future experiments, all the 

 beams, except otherwise mentioned, were cast 

 erect but upside down, as there is an accession of 

 strength from that cause. Those in experiments 

 8, 9, 11, 12, and 21, were elhptical, and were 

 indeed from the model of the three first 

 experiments, its top and bottom ribs being 

 further changed. 



