6o BROOMALL : THE I BEAM. 



a region of danger which should not be underestimated. 

 In conclusion, although the foregoing considerations have 

 not led to results of much practical importance, it is hoped 

 they may at least direct attention to a phase of the subject of 

 internal stress but little treated of in the literature of engin- 

 eering. When the same method of investigation is extended 

 to beams of unsymmetrical cross-section, very interesting and 

 suggestive results are obtained. In a subsequent article the 

 writer hopes to be able to deal with this branch of the subject. 



