80 



MATHEMATICAL AND PHYSICAL SCIENCE. 



[Diss. VI. 



(364.) 

 Commis- 

 sion on 

 railway 

 bridges. 



(365.) 



of the responsibility of the engineer-in-chief. As 

 neither Mr Fairbairn nor Mr Hodgkinson could have 

 incurred any just blame had the vast structure when 

 on the eve of completion doubled up under its own 

 weight, and blocked up, perhaps for ever, the navi- 

 gation of half the Menai Strait, so neither can they 

 possibly claim more than a subordinate share in the 

 success of the undertaking. 1 



I shall here only refer to the work of Mr Edwin 

 Clark, the resident engineer of the Britannia Bridge, 

 for farther details of its principles and construction, 

 and to the report of a royal commission (published 

 in 1849) on the application of iron to railway struc- 

 tures, for many curious researches connected with the 

 subject of this section. In particular, we find a theo- 

 retical and practical solution of the very delicate pro- 

 blem of the influence of the speed of passing loads on 

 the deflection of bridges, to which Professors Willis 

 and Stokes, and ColonelJames,R.E.,are contributors. 



Mr Robert Stephenson is the son of Mr George 

 Stephenson, who will be mentioned in a succeeding 



section. He was born in 1803; educated (in part) at Other 

 the University of Edinburgh, under Leslie, Hope, and ^ or ~ s of 

 Jameson ; he long occupied the chief position in the phenson. 

 locomotive factory established by his father at New- 

 castle, having in the first place constructed under 

 his direction the celebrated " Rocket" engine which 

 gained the prize at the opening of the Liverpool 

 and Manchester railway. To his own exertions, 

 both before and after that period, the locomotive 

 owes much of its present perfection. He surveyed 

 and principally carried through the London and Bir- 

 mingham railway, the second great line in the king- 

 dom ; and he has been engaged in a large proportion 

 of the most remarkable engineering works connected 

 with railways, both in this country and abroad. He 

 has personally superintended the construction of 

 railways amidst the blowing sands of Egypt, and in 

 Norway with its heavy winter snows and deeply frozen 

 soil. His high personal character, both for skill and 

 integrity, has everywhere procured him the respect 

 and confidence of his profession and of the public. 



4. BRUNEL. Self-acting Machinery. 



-The Thames Tunnel. Mr BABBAGE*S Calculating 

 Engines. 



bart Bru- 

 nei. 



(366.) Sir MARC ISAMBART BRUNEL, born at Hacqueville 

 Marcjsam. { n Normandy on the 25th April 1769, was one of the 

 most inventive mechanicians and engineers of his day. 

 As his genius gave a strong impression to contem- 

 porary art, we associate his name with the progress 

 of civil engineering in the earlier part of the pre- 

 sent century, particularly in connection with me- 

 chanism. Like most of his eminent coevals in the 

 same profession, he had not the benefit of a scien- 

 tific education ; but he more than most of them sup- 

 plied its defects by a singular capacity for correct 

 induction and by great mechanical ingenuity. Though 

 a native of France, it was in Great Britain that his 

 talents were to find their full scope, and it became his 

 thoroughly adopted country. 



Disgusted by the horrors of the first revolution, 

 he quitted France in 1793 in the capacity of a com- 

 mon sailor, a position far below that which either his 

 birth or his intellect entitled him to hold, yet in 

 which he made himself remarked by his excellent 

 disposition and mental superiority. His destination 

 was New York, where in 1794 he commenced his 



(367.) 

 His early 

 history. 



( 368> ) 



career as a civil engineer, his boyish tastes having 

 already indicated this as his natural calling. He exe- 

 cuted some considerable works, and planned many 

 more ; it is stated that he there devised the essential 

 parts of his block machinery. About 1799 he decided 

 on settling in England. 



It is probable that his talents and ingenuity alone 

 recommended him to a government employment at a 

 time when the mere fact of his being a Frenchman n s h go- 

 must have acted as a powerful obstacle to his sue- vemment 

 cess. Those who recollect the vivacity and bright 

 intelligence of even his later years, will understand 

 that in his more active days it must have been diffi- 

 cult to refuse Brunei at least a hearing. And it is 

 to the credit of Lord Spencer, then one of the Lords 

 of the Admiralty, and of General Sir Samuel Ben- 

 tham, inspector of naval works, that Brunei was en- 

 gaged in 1802 to superintend the erection of his cele- 

 brated block machinery. 



The invention of self-acting machinery to super- (369.) 



sede the work of artisans was of course not new. Sclf -* ctin 

 mi -n j j.i i -i niachiner 



The saw-mill and the spinning-jenny were already in 



1 It has been alleged that Mr Stephenson's original proposal to allow the suspension chains (which were primarily intended to 

 be used in putting together the tubes in their final positions) to remain in aid of the rigidity of the structure, manifested a 

 want of confidence in his own great idea. But a dispassionate consideration of his evidence before the committee of the 

 House of Commons would alone clearly show (independent of Mr Stephenson's declarations on the subject) that he was 

 forced into the admission that the chains might give an ulterior guarantee against miscarriage of the whole plan, simply to save 

 the bill from being thrown out by the not unnatural incredulity of those to whom a proposal so new, so gigantic, and affecting the 

 lives of eo many persons, as well as so great pecuniary and other interests, was for the first time and suddenly proposed. Be- 

 sides this, even his own coadjutors did not all entirely support him. Mr Hodgkinson, whose character for scientific know- 

 ledge carried great weight with the committee, recommended in his report the ultimate additional security of chains. 



