42 



THE CIVIL EXGIXEER AND ARCHITECTS JOURNAL. 



[February, 



of the Institution, and proposed that the evening meetings should 

 terminate at half-past nine o'clock, in order to afford an opportu- 

 nity for the members and visitors to assemble in the liliiary, and to 

 obtain those personal introductions to each other which constitute 

 one of the great advantages of all societies. 



He then announced, that the Council had, with great pleasure, 

 acceded to the recommendation of the last Annual General Meet- 

 ing, and had invited Mr. Walker, Sir John Rennie, and Mr. Field, 

 the past Presidents, to take their seats at the Council table, in the 

 Council-room, and in the Theatre, as "Honorary Councillors," and 

 that, in future, .all those members who should fill the posts of Vice 

 President and President consecutively, holding the latter position 

 for two years, should be considered "Honorary Councillors"; ex- 

 pressing a hope, that the pjist Presidents might long be spared, to 

 continue that assistance from which the Institution had already 

 reaped so much advantage. 



He then announced, that, as the representative of the Institu- 

 tion, he had been nominated a member of the Royal Commission 

 for the promotion of the Exhibition of the A^'orks of Industry of 

 all Nations, under the auspices of H.R.II. Prince Albert, and re- 

 quested the aid and cordial concurrence of all the members in that 

 "real Peace Congress." 



Mr. Cubitt then proceeded to notice the principal engineering 

 works now ^in progi-ess, or lately completed, as arranged under 

 their respective heads, as follows: — 



Tubular Bridges. — Although during the past year there has not 

 been so great a demand for the talents, or the energies of en- 

 gineers, several remarkable works have been finished, or have far 

 advanced towards completion; I will allude briefly to a few of 

 them, and if others of importance escape notice, it must be attri- 

 buted to the engineers not having brought accounts of them be- 

 fore the Institution, or even incidentally mentioned them in the 

 discussions. Among these, the tubular bridges across the river 

 Conway and the Menai Straits, are pre-eminent, for the boldness 

 of the conception, the scientific simplicity of the design, and the 

 difficulty of the execution. In tracing the original idea of the 

 most advantageous disposition of a certain amount of material, 

 in a tubular form; the more definite conception of a hollow beam, 

 to permit the passage and support the weight of an engine and 

 train; the experiments for determining the proper distribution of 

 the material, to prevent compression, or disruption; the arrange- 

 ment for the construction and building up these gigantic masses 

 of material; the means of floating them to their situations, and of 

 raising them to their ultimate destination, at an elevation of 102 

 feet above the sea (at high water of spring tides); — we must feel 

 justly proud of possessing among us the man whose comprehensive 

 mind could originate this magnificent design, and so successfully 

 perform a portion of the work as to leave no doubt of its ultimate 

 accomplislinient. The world already duly appreciates this great 

 undertaking, and we should not be behindhand in testifying our 

 estimate of the bold conception of Mr. Robert Stephenson in the 

 original idea, his professional skill in the design and execution, 

 his care and caution in availing himself of the talents and expe- 

 rience of Mr. W. Fairbairn and iSIr. Eaton Hodgkinson, whose 

 scientific investigations respecting the strength of cast-iron, are 

 so well known to the world and so highly appreciated by our pro- 

 fession, and his intrusting the general construction and elevation 

 to Mr. Frank Forster and Mr. Edwin Clarke. Upon the merits of 

 all these gentlemen we may look with pardonable pride and par- 

 tiality; their labours speak for themselves. However advanta- 

 geous may be the results of this construction, in facilitating an im- 

 portant communication I shall have occasion to allude to here- 

 after, it has already been extremely useful in directing attention 

 to the more general employment of wrought iron for the purposes 

 to which it had not previously been deemed applicable ; and it will 

 be found that its introduction to structures of all kinds will he- 

 come more common, exactly as the method of using it becomes 

 better understood. 



Report on Iron. — M.iy I here be permitted to diverge for an in- 

 stant, in order to direct attention to a subject of considerable im- 

 ])0rtance to the profession. In the year 18+7 a commission was 

 appointed (of which I was named a member) for the purpose of 

 inquiring into the conditions to be observed by engineers, in the 

 application of iron, in structures exposed to violent concussions 

 and vibration; and for endeavouring to ascertain such principles 

 and forms, and to establish such rules as should enable the engineer 

 and the mechanic, in tlieir respective spheres, to apply the metal 

 with confidence, and should illustrate, by theory and experiment, 

 the action which would take place, under varying circumstances, 



in the iron railway bridges which had been erected. Numerous 

 witnesses of great theoretical attainment and practical experience, 

 were exan\ined before the commission, and a very interesting series 

 of experiments was carried on, for ascertaining certain points re- 

 lative to the compression and extension, the tensile and crushing 

 strength, the effect of statical pressure, and of vibration, concus- 

 sion, &c. The result of this laborious investigation is (in the 

 words of the report, which is now before the public) that 'con- 

 sidering that the attention of engineers has been sufficiently 

 awakened to the necessity of providing a superabundant strength 

 in railway structures, and also considering the great importance of 

 leaving the genius of scientific men unfettered for the development 

 of a subject as yet so novel and so rapidly progressive as the con- 

 struction of railways, we are of opinion that any legislative enact- 

 ments with respect to the forms and proportions of the iron struc- 

 tures employed therein would be highly inexpedient.' It would be 

 foreign to my present purpose to enlarge upon the importance of 

 this decision; but I must recommend the Report to your careful 

 perusal and consideration. 



The Harbours of Refuge now in progress are works of national 

 utility. Those at Dover and in the Channel Islands, by Mr. 

 Walker, deserve particular attention. The former has already 

 produced extraordinary effects on the litoral currents and in the 

 movement of the shingle on the coast, and the latter will afford 

 protection to the storm-driven mariner, where he before expected 

 only danger and death. The Breakwater off Portland Island is 

 important, not only as utilising one of the finest bays on our coast, 

 but also as an immense engineering work, intended to be executed 

 almost entirely by convict labour, and on that account it was 

 necessary to render its construction as simple as possible. This 

 has been achieved by Mr. Rendel, whose design is to form along 

 the site of the intended breakwater a timber staging, carried upon 

 screw piles; on this will be laid railways connected by inclined 

 planes with the quarries on the hill, whence the trains of stones 

 will be brought, and their contents be distributed simultaneously, 

 and in regular thickness over given areas, enabling a careful ad- 

 mixture of large and small-materials to be effected, and the whole 

 mass to rise gradually to the surface, and being thus self-support- 

 ing, to prevent the washing away of the materials, which has been 

 experienced in other works of a similar nature. The harbour at 

 Holyhead, and the new docks at Leith and at Grimsby, also by Jlr. 

 Rendel, do equal credit to his comprehensive designs and his exe- 

 cutive skill. 



Lighthouses. — In conjunction with these maritime works may be 

 mentioned two lighthouses, both possessing remarkable features. 

 The first is an iron structure, erected on the Bishop's Rock, by Mr. 

 Walker. It is situated about 30 miles from the Land's End, Corn- 

 wall, and four miles due west from the St. Agnes Lighthouse, 

 which would probably not have been constructed had our ancestors 

 possessed the modern facilities for the execution of works of this 

 nature. The position is more exposed to the force of the Atlantic 

 than the famed Eddystone Lighthouse, and the surface of the rock 

 is of such an outline as scarcely to admit of a solid building. It 

 was therefore determined to erect such a structure as should offer 

 little or no opposition to the waves, and bear a light at such an 

 elevation as to render it extensively useful. Six hollow cast-iron 

 columns, with a strong bar of wrought iron in each, sunk to the 

 depth of five feet into the rock, forming at the base a hexagon 30 

 feet in diameter, and tapering upwards, support, at a height of 

 about 100 feet, the dwelling of the three light-keepers, with stores 

 and provisions for four months, the whole being surmounted by the 

 lantern. The access to the dwelling is by a centre column of cast- 

 iron, containing a spiral staircase. The difficulties overcome in 

 the execution of this bold design can scarcely be appreciated with- 

 out a more detailed account of it, which, however, I trust, will be 

 laid before you during this session. — The other is a stone light- 

 house, called the Skerryvore, erected by Mr. .Man Stevenson, on a 

 small desolate rock situated about 11 miles W.S.W. of the island 

 of Tyree, and 90 miles from the mainland of Scotland. The rock is 

 exposed to the fury of the North Atlantic, and is surrounded by 

 an almost perpetual surf. The talent and perseverance ot the en- 

 gineer enabled him, however, to complete, without loss of life or 

 limb — great as were the difficulties he had to contend with — a 

 structure far exceeding the dimensions of the famed Eddystone 

 and Bell Rock Lighthouses, their relative heights being — the Eddy- 

 stone, 08 feet; the Bell Rock, 100 feet; the Skerryvore, 138 ft. 

 6 in. The difficulties of the construction, the merits of the struc- 

 ture, and the system of lighting, are so fully described in Mr. 

 Stevenson's published account of it, that it is not necessary for me 



