532 THE STRENGTH 



63. We will now proceed to the practical 

 application of the results from the beams I 

 have experimented on generally ; especially 

 with respect to those that have been considered 

 as the best. — It gives me great pleasure that 

 they are likely to be adopted, and particularly 

 that the commencement is in such a quarter: 

 Mr. John Kennedy, who felt an interest in the 

 experiments, and favoured me with his presence 

 at many of them, informs me, that he shall 

 employ the beams in some erections he is going 

 to make : and Mr. Stephenson, I understand, 

 will use them in a railway bridge crossing 

 Water-street, Manchester.* 



64. The investigations relative to the strength, 

 given in the early part of this essay, are such 

 as apply, and ought to be used, while the 

 elasticity is perfect, or nearly so ; but to find 

 the ultimate strength, or that exerted at the 

 time of fracture, in such forms of section as 

 we have found to be the best, the experiments 

 will supply us with the following much easier 

 general theorem. A theorem which I think 

 will be sufficiently simple and correct for all 

 practical purposes. 



* Since the above was written, Messrs. Fairbairn and LilHe 

 have used them to a considerable extent, for Factories, Bridges, 

 &c. in diflferent parts of the Country 



