2G ANNUAL OF SCIENTIFIC DISCOVERY. 



earned a web of iron completely through it, in some cases passing through 

 the bulwarks, and sometimes avoiding them. 



Mr. Ritchie (surveyor of Lloyd's Register) said he should like to hear 

 something from Mr. Russell on the subject of rivets. 



Mr. Russell said that was a most important matter in the construction of 

 iron ships. He had recently inspected a vessel returned from a voyage, and 

 found that the heads of at least one thousand rivets were off. How they 

 came off was a mystery to him ; but he gave a very modest rap with a 

 hammer, and one of the rivets dropped out. He had adopted the system of 

 conical riveting, which he found to answer very well, as, when the head was 

 gone, the rivet was perfectly water-tight. 



Mr. Napier (of Glasgow) observed that he did not approve of the tubular 

 system advocated by Mr. Fairbairn; and it must be remembered that a sta- 

 tionary tubular iron bridge had not to contend with the constant strain of 

 the sea. Many and conflicting opinions prevailed as to the best form of the 

 keel; some were for having it flat, others sharp and perhaps both were 

 right. (Laughter.) For his own part, he did not build a vessel to goon 

 the rocks; but if she were taken there he could not help it. If they could 

 possibly arrive at the absolute breaking power of the sea which an iron 

 vessel would bear, it would be a great discovery. He agreed with Mr. Scott 

 Russell, that it was not in the power of man to build a ship which would be 

 able to bear up against the breaking power which the Royal Charter encoun- 

 tered as the sea went over her broadside. 



Mr. Fairbairn again addressed the meeting, expressing his opinion that 

 iron ship-building was at present in a transition state. They required to 

 have better and stronger plates ; and if owners would only give a fair price 

 for their vessels, many catastrophes which resulted from the use of bad iron 

 might be averted. 



ON THE EFFECTS OF VIBRATORY ACTION AND LONG -CONTINUED 

 CHANGES OF LOAD UPON WROUGHT-IRON GIRDERS. 



In a paper presented by Mr. Fairbairn to the British Association for 1860, 

 the author detailed the results of a set of experiments, having for their 

 object the determining of matters with which the public are intimately con- 

 cerned, viz., the efficacy of girders supporting bridges over which raihvay 

 trains are constantly passing. It is well known that iron, whether in the 

 shape of railway axles or girders, after undergoing for a length of time a 

 continued vibratory or hammering action, assumes a different molecular 

 structure, and, though perfectly efficient in the first instance, becomes brittle, 

 and no longer capable of sustaining the loads to which it may be subjected. 

 Mr. Fairbairn stated that the practical conclusion to which his experiments, 

 so far as they had at present gone, would lead, was, that a railway girder 

 bridge would, irrespective of other causes, last a hundred and fifty years. 



IMPROVEMENT IN THE STEAM-ENGINE. 



An improvement in the construction of steam-engines recently devised 

 and patented by Richard Barton, of Troy, N. Y., has for its object, first, to 

 enable a steam-engine having a long cylinder, and consequently a long 

 stroke of piston, to be brought within a comparatively small space; and, 

 second, to enable two complete revolutions of the crank shaft to be pro- 



