THE SCIENTIFIC PAPERS OF 



acted very detrimentally to the introduction of that invention. It 

 was with regard to such unauthorised applications of inventions 

 that he felt rather strongly, and he therefore wished to say some- 

 thing on that subject. 



In the discussion of the Paper 



"ON STEEL FOR STRUCTURES," 

 By MR. E. MATHESON, 



DR. SIEMENS* said, he thought the author had brought forward 

 one of the vexed questions of the day, viz., to what extent steel 

 should be trusted for engineering structures. In consequence of 

 rules which had hitherto been followed by the Board of Trade 

 with regard to steel, that material had not come unto use for 

 engineering purposes except under special circumstances ; and 

 although he believed that at the present time the officers of the 

 Board of Trade were anxious to study the material, and gain from 

 their own observation the experience necessary to give confidence, 

 the public were still without the result of their labours in that 

 direction. Steel differed very materially from iron in regard to 

 the variety of strength and other qualities which it was able to 

 assume. There was steel which resisted a tensile strain of 

 nearly 80 tons, and whose elastic limit exceeded 40 tons; with a 

 very slight modification of its composition, it would assume an 

 ultimate strength of only 27 tons ; but on the other hand it 

 would have acquired a power of elongation amounting to nearly 

 25 per cent, before breaking took place. It was, therefore, an 

 important question, which of the endless varieties of steel between 

 those limits was the best for engineering purposes. He thought 

 it would be impossible to give one satisfactory answer to a 

 question of such scope. It required a careful study of the 



* Excerpt Minutes of Proceedings of the Institution of Civil Engineers, Vol. 

 LXIX. 1882, pp. 36-39 and 58. 



