1 70 THE SCIENTIFIC PAPERS OF 



to remove the ash so as to continue the combustion under 

 favourable circumstances, and this difficulty has apparently been 

 successfully overcome. He thought the thanks of the Institution 

 were due to Mr. Head for the admirable manner in which he had 

 investigated the subject and brought it before the members. 



In the discussion of the Paper 



"ON EXPERIMENTS RELATIVE TO STEAM 

 BOILERS," by Mr. WILLIAM BOYD, 



DK. C. "W. SIEMENS* remarked that the paper was exceedingly 

 gratifying to himself, inasmuch as it contained results arrived at 

 by an engineer who had evidently gone very systematically to work 

 in testing material, and had not refrained from bringing the 

 results he had obtained before that Institution. The first news 

 he had had of this application of Landore steel was unfortunate. 

 He was told that the steel had in one instance at least entirely 

 failed to stand the test. Mr. Boyd had now brought before the 

 meeting the particular circumstances under which his apparent 

 failure arose. A test plate had been fastened between two plates 

 of iron ; and when the tensile strain was applied, the steel, instead 

 of elongating 20 or 25 per cent, as was expected, and of breaking, 

 as was also expected, across the rivets, took its own course and 

 broke through the fastening, along a line of fracture some 20 per 

 cent, stronger than the line of least resistance. It was inferred 

 from that experiment that such steel after all must be an unreliable 

 material ; but when he saw the details of the experiments he 

 immediately suggested that the cause of failure would probably be 

 found to lie in the mode in which the fastening had been made. 

 Mild steel or homogeneous iron was a material that yielded very 

 much before rupture, provided the tensile strain was applied fairly 



* Excerpt Minutes of Proceedings of the Institution of Mechanical Engineers, 

 1878, pp. 233-236. 



