Ol^ IRON BEAM9. 4J1 



Other side upwards, the part ACB being incocQ- 

 pressible, the deflection must arise from the 

 extension of DFE, and consequently would 

 be many times as great as when the casting 

 was the other side upwards, DFE being so 

 much less than ACB. 



2nd. Suppose bodies to be inextensible, then 

 if the back of the casting be upwards, the 

 deflection will wholly rise from the compression 

 of DFE, and will be many times greater than 

 if DFE had been upwards, when it must 

 have arisen from the compression of ACB. 



ntoix 

 3rd. Suppose the extensions to be equal to 

 the compressions, from the same forces ; the 

 deflection in this case will be the same from 

 the same force, whether the rib DFE be down- 

 wards or upwards. tis 



i<.om 



20. We will now collect in a tabular form, 



the principal results from the experiments, and 



see how near they correspond to any of the 



above suppositions. 



