OF IRON BEAMS. 451 



inches deep in the middle, and 5 feet long, and 

 were supported on props just 4 feet 6 inches 

 asunder. The lever was placed at the middle 

 of the beam, and rested on a saddle, which 

 was supported equally by the top of the beam 

 qnd the bottom rib, and terminated in an arris 

 at its top, where the lever was applied. The 

 deflections were taken, in inches and decimal 

 parts, at or near the middle of the beam, as 

 mentioned afterwards. The weights given below 

 are the whole pressure, both from the lever and 

 the weights laid on, when reduced to the point 

 of application on the beam. The dimensions 

 of section in each experiment were obtained 

 from a careful admeasurement of the beam 

 itself, at the place of fracture, which was 

 always very near (usually within half an inch 

 of) the middle of the beam, the depth of the 

 section being supposed to be that of the middle 

 of the beam, or 5f inches. 



As the experiments were made at different 

 times, and there might be some variation in 

 the iron, though it was intended always to be 

 the same, a beam of the same length and 

 depth as the others, but of the common 

 form, always from the same model, was 

 cast with each set of castings for the sake of 

 comparison. 



3 l2 



