278 



THE CIVIL ENGINEER AND AUCIIITECT'S JOURNAL. 



LSeptembeb, 



The wants of the present rlny require vast appliances, and the con- 

 sideratiiin of the instruments wliich are at our disposal is not 

 among the least pleasing meditations, Hhile easting a hojieful 

 glance at tlie future. Viewed under the inspiration of all these 

 considerations, tlie Britannia Bridife seems invested with an influ- 

 ence, the possihle results of which can hardly he ajipreciated. It 

 is not only a fjreat work in itself, hut it is an extension of mechani- 

 cal |)ower such as enahles us to work out still frrander designs. 

 Kverything which is a means to a great end calls for our ohserva- 

 tion; but those which are the most i>owerful in their results, whe- 

 ther a telegraph wire or the beam-bridge, justly claim our most 

 serious attention. 



The engineer, in contemplating the structures which have given 

 rise to these remarks, neither irrelevant, we hope, nor unworthy 

 of them, will chiefly have regard to two conditions — first, as to 

 the means of completely imitating them, and next, as to the possi- 

 bility of the application of tlie same construction on a larger 

 scale. As a record of the Britannia or Conway Bridge, we 

 should care little for any work; but it is in their results, in their 

 influence, that our interest lies. Mr. Edwin Clark, the author, 

 lias well understood the conditions reijuired, and he has therefore 

 laid down a text-lio(d<, whii^h will not merely be read and re- 

 ferred to, but which will be worked out by the engineer engaged 

 in some like undertaking, perhaps among the steppes of Russia, 

 the jungles of Ilindostan, or the prairies of the far west. To 

 enable this to be done effectually, it was needful not only to 

 3cscrihe the works, and the way in which they were hnilt up, hut 

 to investigate the jirinciples in conforming to which their stability 

 depends. In the case of an ardi or suspension bridge, or a light- 

 bouse, this has been already done; but the hollow beam being 

 new, it will he seen how great is the task imjiosed upon the author; 

 and hence the work, being carefully and ably performed, as here, 

 how valuable in its teachings. 



Such then is the book before us, and familiar as its subject may 

 at first sight appear, it is most difficult for us, within our limits, 

 properly to bring it under the notice of our readers, for we should 

 be obliged to enter into many details at the same leneth as the 

 author, or to reproduce his statements. We are therefore obliged 

 to adopt a less systematic course, and taking it as our text, offer 

 such observations as occur, leaving the analysis of the book to our 

 readers, who will not wait for our bidding to buy it, and who are 

 as it were constrained to read wli.it is the standard work of engi- 

 neering literature in the present day. 



First, wo must allude to the feeling of gratification which all 

 members of the profession must entertain towards Robert Ste- 

 phenson, for promoting the publication of this work. It is a 

 graceful recognition of the duty incumbent on all to contribute to 

 the common stock of knowledge, from which each gleans, and none 

 more than those whose own aoliievements are greatest; and we feel 

 a personal satisfaction in having constantly urged on the profes- 

 sion the discharge of this duty, because we know that we are 

 answered by the sympathy of those whom we address. We may 

 be forgiven for this personal allusion, because in a profession so 

 newly risen to a great height, neither are the duties of its mem- 

 bers well umlerstood, nor tlie value of a technical periodical ]iro- 

 perly appreciated. We call the attention of our readers to our- 

 selves, because it is as a means of serving their interests. The 

 more i-eadiness shown in giving information to the public, the 

 greater the aggregate result and the benefit to each; for the 

 influence of the press is not confined to general suggestions, being 

 more especially owing to the diffusion of information to an extent 

 which is little known, and can theref(n-e hardly be conceived. In 

 Mr. Clark's work, at p. e/il, will be found a reference to our 

 pages, and others are n\ade by him and Mr. Stephenson to our 

 contemporaries; while within the last few months alone, our pages 

 have been acknowledged as a source of iurorniation to members of 

 the profession in Rio Janeiro, in Canada, and in Ilindostan. Who 

 cares about gi\iug iuforiiKition to others in India or America, yet 

 it was by gleaning infornuition as to a covered viaduct in America 

 (p. 23), as to an accident in a dockyard at home (p. ISO), that 

 Robert Steplienson obtained the corollary evidence on which to 

 justify his vast design. We do not feel disa|)pointed with tiie suc- 

 cess of our exertions — far from it, they are beyond what we could 

 ever have expected; but we speak because we wish to stimulate 

 the "reat body of engineers to the communication of information 

 npon which too many are neglectful, either as thinking too much 

 of their works, and' selfishly keeping their knowledge to them- 

 selves, or thinking too little of what they see, and i>assing over 

 what they think trifles. 



Under these circumstances, Mr. Clark's book is invested with 



the character of a record by its maker, of a great undertaking 

 rather than the narration <if an historian. Robert Stephenson has 

 not only supervised the whole work, hut he has written a section 

 of it ; it contains bis letters and reports. Rut, above all, Mr. Clark 

 was in this whole business his bosom friend and helpmate, knowing 

 of all that was done; partner of every doubt, of every fear ami 

 every hope; jiresent at the rise of each new suggestion, and taking 

 part in carrying it to fruition. The book justifies, therefcne, the 

 character we have given it, of being one of the great standard 

 works, and we liope many others are to come. In many professions 

 the reward of excellence is so narrow that it is beyond the 

 power of the members to incur any large pecuniary contribution; 

 Imt the earnings of our great engineers have been so princely as 

 to leave no excuse of this kind, and little time ought to pass 

 before the gigantic undertakings of the day are as well commemo- 

 rated as the Britannia Briilge, of which we are now speaking, the 

 Menai Bri<lge by Mr. Provis, the Plymouth Breakwater by Sir 

 John Rciinie, and the Skerryvore Lighthouse by Mr. Alan Steven- 

 son. One very memorable circumstance connected with the Bri- 

 tannia Bridge is, the union in its production of the resources of 

 theoretical research and of practical aciiuirements, and the har- 

 mony and ze;il with which, with a well-known exception, so many 

 men of various aciiuirements co-operated in the achievement of 

 this design. Whether it was from fellow-feeling for the engineer, 

 burdened with a task almost impossible, or whether with the 

 earnest desire of ensuring success for a grand conception, certain 

 it is few men have had so many or so able beljimates. The report 

 of the Admiralty engineers. Sir John Rennie and Mr. Rendel, 

 made abortive a very admirable design; and it appears very (|iies- 

 tionable, whether in the conditions they imposed, they did not 

 seek to make the passage of the railway imprissibl?, and to favcur 

 the Porth Dynllaen plan. The tribunal of the Parliamentary 

 Committee was not the most encouraging for the announcement of 

 the new plan; and incredulity was as strongly expressed at the sug- 

 gestion of a beam iaO feet long, as when the father before a like 

 audience spoke of locomotives running thirty miles an hour. If 

 Robert Stephenson felt sei'iously the responsibility thrust upon 

 him, he soon received the assurance of co-operation and support. 

 Not only did he have the assistance of Mr. Fairhairn, Professor 

 Eaton Hodgkinsin, and Mr. Edwin CUark, but h^ found a liberal 

 counsellor in tl;e Astronomer Royal (pp. 483, 511), and practical 

 supporters in Mr. Brunei, Mr. Tierney Clark, Mr. John Laird, and 

 Mr. Miller. When it is remembered the feud was still raging as 

 to the broad gauye and the narrow gauge, the atmospheric railway 

 and the locomotive, in wliich the two great engineers were pitted 

 against each other, and tliat throughout they have been rivals for 

 fame, it is not the less remarkable, and we are sure not the least 

 pleasing, to find Robert Stephenson and Brunei working freely and 

 earnestly together, and it is an event equally honourable to both. 

 Throughout we find frequent references to communications from 

 Brunei (pp. 101, 4.37, 461, 4S8, 510, G43, (iSO), and a most inte- 

 resting description of his original application of the principle to a 

 circular beam, 309 feet long, for a bridge over the \V'ye (p. 102). 

 All the experience be had acquired in getting up the llungerford 

 Bridge and the Clifton Bridge was readily communicated, as well 

 as that of Mr. Tierney Clark, as to the' Pesth and other great 

 suspension bridges. 



Another memorable circumstance was the costly series of experi- 

 ments, and the lengthened scientific investigation forming part of 

 the preparations. Distinct experiments were carried on by Mr. 

 Fairliairn, Mi-. Eaton Hodgkinson, and Mr. Edwin Clark, and 

 those of Sir Mark Brunei and his son were freely communicated. 

 These experiments were followed by a careful and laborious ma- 

 thematical investigation, conducted by Mr. Eaton Ilodjfkinson, 

 checked by Mr. Edwin Clark, and laid for revisal before the 

 Astronomer Royal, who, in one instance (p. 513), pointed out an 

 erroiuMiiis deduction. The experiments began with small tubes 

 and other slight models, and extended to a costly model made one- 

 sixth of the size of the Britannia tube, or no less than seventy-five 

 feel long (p. 184). Of course, the material being only in cubic pro- 

 jiortion to that of the great tube, w.is very small (1 to 21(i), but the 

 model w.isso large as to give a near approximation to the condition 

 of the gigantic structure. The experiments of Brunei on a beam of 

 66 feet long (p. 437) are likewise on a large scale; and what may be 

 called the auxiliary exiieriments are likewise nnapproacbablc under 

 ordinary conditions. Such are those of Mr. Fairhairn on an iron 

 steam-ship 200 feet long, with 1200 tons of machinery in the middle; 

 and such are those on the tubes themselves while on the platlorms. 

 The bridges were likewise the subject of experiment, and the 

 opporliinity was thus given of observing a beam 1511 feet long, 



