TRANSACTIONS OF THE SECTIONS. 209 



varied from a per cent, to nearly 1 per cent. ; yet with this small variation in the 

 carbon the strength ranged from 33 tons to nearly .53 tons per inch ; and the duc- 

 tilit}^ represented by the ratio wliicli the fractured area bore to tlie orio-inal section 

 of the bar, varied from five tenths in the tough qualities, until in the harder 

 samples there was no diminution perceptible. 



All these materials are called steel, and have the same external appearance ; but 

 possessing, as they do, such a range of strength and such a variation in ductility, 

 it becomes absolutely essential that there should be some classification or means 

 of knowing the respective qualities among them. 



The want of such classification casts an air of uncertainty over the whole ques- 

 tion of steel, and impedes its application. To this want of knowledge is to be 

 ascribed the circumstance that many professional men regard the material as 

 altogether unreliable ; while large consumers of steel, in consequence of the un- 

 certainty of the quality they buy in the market, seek to establish works on their 

 own premises and make their own steel. 



This step has already been taken by one of the large railway' companies, and is, 

 as I am informed, contemplated by one of the principal constructive departments 

 of the Government. 



My attention has been recently and forcibly directed to the importance of steel 

 through having been called upon, in conjunction with Mr. Bidder, Sir John 

 Hawkshaw, Mr. Harrison, and Dr. Pole, to report upon the magnificent work 

 designed by Mr. Bouch for crossing the Firth of Forth. This great work consists 

 of a stiffened suspension bridge in two spans, each of 16G0 feet between the 

 supports. 



To construct this work in iron, with a working strain of 5 tons to the inch, would 

 involve such weights of material and magnitude of strain as to render it virtually 

 inj practicable ; but in tough steel, capable of bearing 8 tons per inch, it is praticable 

 to accomplish it and even larger spans. 



Mr. Bouch has designed the chains of this bridge to be made of steel ; and in 

 addition to the honour which must attach to his name as the originator of this 

 great and important work, he is further entitled to the merit of being the first 

 engineer to break through the restrictions which confine om- engineering structures 

 to wrought iron, and to brave the difficulties which surround the employment of 

 steel for railway works in this country. 



I ought, I know, to apologize for detaining you so long on this one question of 

 steel, but I consider that the difficulties under which it is placed are affecting 

 interests of considerable importance. 



Not only is a large and useful field for the employment of steel practically 

 closed, but the progress of improvement in engineering structures is impeded 

 both in this countryand in other parts of the world where English em'^ineers 

 are engaged. 



For in consequence of the impediments to its en:ployment in England, very few 

 English engineers turn their attention to the use of steel. They are accustomed 

 to make their designs for iron, and when engaged in works abroad where the 

 Board of Trade rules do not apply, they continue for the most part to send out the 

 old-fashioned ponderous girders of common iron, in cases where the freio-ht and 

 difficulties of carnage make it extremely desirable that structures of less weight and 

 more easy of transport should be employed. 



In conclusion, and while thanking you for the patience with which you have 

 heard me on this subject, I would observe that we possess in steel a material which 

 has been proved, by the numerous uses to which it is applied, to be of great 

 capability and value; we know that it is used for structural pm'poses in other 

 countries, as, for example, in the Illinois and St. Louis Bridge m America, a 

 bridge of three arches, each 500 feet span ; yet in this country, where "modern steel" 

 has originated and has been brought to its present state of perfection, we are 

 obstructed by some deficiency in our own arrangements, and by the absence 

 of suitable regulations by the Board of Trade, fi'om making use of it in engineering' 

 works. 



And I have considered it right to draw your attention to the position in which 

 this question stands, well knowing that I eould not address any body of gentlemen 



