OF IRON BEAMS. 4H 



but the matter seemed to be too important to be 

 allowed to pass without some further investi- 

 gation, and especially as we should be enabled 

 at the same time to determine what influence 

 a change in the depth of one of our beams 

 would have upon its strength, every other 

 dimension remaining the same. For these 

 purposes, therefore, I made the following 

 experiments. 



/ In these, and indeed in all the future experi- 

 ments, the same sort of beam was used as that 

 in our last, and which was described immediately 

 before expt, 14 ; it was broke too in the same man- 

 ner. There was, however, this slight difference, 

 that there the parabolic base was but just equal 

 in length to the distance between the supports, 

 and the beam had its ends rendered a little 

 wider and longer with matter attached to them 

 to lie on the props ; but here the parabola was 

 made 6 inches longer than the distance between 

 the props, in order that 3 inches of it might 

 lie upon them at each end ; this was done to 

 render the beam capable of bearing more 

 toward the ends, as there was some doubt 

 whether in the preceding experiments the 

 ends were not a little too weak. The beams 

 were all cast 7 feet 6 inches long, and were 

 supported by props 7 feet asunder j they we^ 

 3 Q 2 



