8fi 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



rMARfiH, 



is deposited. It is by observing tlicse results, that in planning a 

 harbour for Hastings, we ascertain the general laws by which the 

 engineer must be guided. 



We may now restrict our observations to the localities of the 

 English coast, along the British Channel, and, passing from Land's 

 End up to the Isle of Portland, we see that the Chesil Bank is the 

 first decided accumulation of drifted shingle. The projection of this 

 isle, however, forcing the tidewave southward, causes it to run north- 

 ward, again, with great force, and scour out the Bay of Weymouth. 

 We next observe the Isle of Wight taking the position and form of a 

 geological deposit, projected from the headlands of St. Alban's and 

 Durlestone ; and opposite the great fresh-water drain of Southamp- 

 ton Water. In Swanage, Studland, ToUande, and Colwell Bays; 

 and in the Solent, Southampton Water, and Spithead, a deflection of 

 the tideway on shore, and, according to an angle of incidence, 

 operating in conjunction with the Isle of Wight, has preserved deep 

 water, and a continuous navigation. Between Selsey Bill and 

 Beechey Head, we observe another of those undulations seaward, 

 and deflections on the line of shore again, which have more or less 

 presei-ved continuously deep water. Beechey Head having driven 

 the tideway southward, necessarily causes it to run on shore again, 

 according to the angle of incidence on which it has been pressed 

 seaward, whence we are able to assign a distinct cause for the pre- 

 valence of permanently deep water in Pevensey Bay, and up to 

 Hastings. This may be regarded as so far encouraging for the success- 

 ful construction of the harbour proposed ; while the influence of the Isle 

 of Wight on the navigation of the Solent, Southampton Water, and 

 Spithead, gives an exact model, on a large scale, perfectly applicable 

 for planning a harbour, on reduced proportions, for Hastings. In so 

 much the Bay of Hastings resembles that of Whitehaven, as scoured 

 by the headlands of St. Bees in south-west gales ; one of those places 

 where (see vol. 1, page 337, Civil Engineer and Architect's Journal) 

 in the plan of a harbour, "our best engineers have been baffled, and 

 all their operations disconcerted." Why ? Because they failed in 

 combining and preserving smooth water, and an adequate tidal scour. 



Mr. Tait's plan for forming isolated harbours proposes to meet the 

 objection arising from the drift of shingle. But as there is no tidal 

 scour provided foi', though shingle were disposed of along shore, 

 might not silt eventually choke such a harbour up ? The uncer- 

 tainty of the plan, its obvious expensiveness, its distance from the 

 shore, and an exposed locality, however ingenious and able the 

 scheme may be, involve objections which are more easily started than 

 answered. Were his plan, nevertheless, provided with a double en- 

 trance, under the terms which prevail in the instance of Hastings, 

 a requisite scour might be insured, a main objection obviated, and a 

 harbour of isolation brought nearly in communication with the town. 

 In the first place, therefore, taking the features of the Isle of Wight 

 as the model of a protected tideway and harbour for Hastings, the 

 following plan might answer the means of expenditure and the pur- 

 poses anticipated. Even its faihire in part, by carrying out further 

 works on the dotted lines, would give it all the advantages of the 

 double harbour system, an interior scour, and that of isolation, a, a, 

 the west and east walls ; 6, the breakwater. 



^^m 

 ^^w. 





In the foregoing outline, it is proposed that each succeeding step of 

 the plan shall be determined or varied according to the practical re- 

 sults previously shown. In the first place, the breakwater b would 

 be constructed when a scour would commence, of which the extent 



and direction should be closely watched. Next the west and cast 

 walls mig:ht be commenced and carried out according to the opera- 

 tions exhibited by the progress of the work. These finished, tlie in- 

 terior scour of the harbour, if insufficient, w»uld suggest the exten- 

 sion of the breakwater still further along the dotted line rf, until the 

 scour «ithin the liarbour should be sufficiently powerful, by which 

 the plan of the liarbour would bear a resemblance to the Isle of Wight 

 pressing upon the waters of Southampton, the Solent, and Spithead. 

 The scour thus established would then determine the position and 

 figure of a quay on the side of the dotted line c ; and if these various 

 works, when combined as a whole, should fail in afliirding a harbour 

 of refuge, then the dotted line, e, might be built in addition, and thus 

 give an inner harbour, g, and an outer harbour,/; or partly an isolated 

 harbour. Thus vessels taking refuge in the one, could be subse- 

 quently towed into the other by a steam-tug, if required ; and docks 

 might then be added as a security and convenience to the whole. On 

 the plan here detailed, the entire works Mould be determined by 

 practical results, errors would be corrected, and no step in the pro- 

 cess need be regretted or retraced. 



What has been here sketched out must, however, be considered 

 merely as a free outline, subject to remodificationinits details, rather 

 than as an absolute or invariable plan. The convexity of the curved 

 line, 6, is intended to scour and preserve deep water along the line c f 

 the concave curve opposite thereto, marked c ; and if the rim of 

 water along these curved walls were too powerful, such defect might 

 be mitigated by adding undulating jetties at the dotted points, /, /. 

 Ever keeping experimental results in view, the spaces of the en- 

 trances, y and /(, and those of h and i, if called for, might be in some 

 measure determined by such a rule. 



Though the harbour, g, might appear somewhat exposed to either 

 eastern or western gales of wind, from having double entrances, yet 

 the smoothness of regulated water flowing in continuous lines obvi- 

 ates its rebound, and more than compensates the security which a 

 single entrance affords. The breadtli of water within the harbour, 

 g, exceeding the space of the entrances, /and k, smooth water and 

 an accumulation of silt would be a more likely objection than the 

 excessive force of a passing and onward current. A material advan- 

 tage in disposing tlie lines of walls in curves and diagonally, in place 

 of at right angles to the course of the tideway, would be that of 

 smoothing the water, easing the various works, cheapening their 

 construction, and augmenting their security, besides directing the 

 force of the tidewave on those points mainly where a scour might be 

 desirable, and giving the greatest depth of water along the proposed 

 line of wharf. 



SCHOOL OF CIVIL AND PRACTICAL ENGINEERING, 

 AT THE Scotch Naval and Military Academy, Edinbdrgh. 



We had pre|iared last monili an account of the Eng-ineering School at 

 Edinburgh ; but the pressure of other matter compelled its delay. We 

 arc now, however, by tlie kindness of T. Comptoii, ivq. (formerly of 

 Woolwich), the Professor of Civil Engineering in the Academy, 

 enabled to give a better description than would otherwise have been in 

 our power. The class of civil engineering- has been in activity since 

 November, 1835, and consists of the departments of mapping and 

 plan-drawing, construction, practical surveying, and administration, 

 or the mode of making out specitications and estimates. The class 

 is actively employed in summer in surveying the most interesting 

 localities in the neighbourhood of Edinhursh ; and its success under 

 its able conductor has been such as to Icjil the diiectors to form a class 

 for practical engineers. This is to be divided into the sections of draw- 

 ing, iiattern-making, moulding, and ea-iting; millwright-work, theory 

 and construction of steam-engines, miscellaneous machinery, boiler- 

 making, and locomotive machinery. The course of instruction in this 

 latter department is intended to be three or four years; and the terms 

 thirty-two guineas the first year, twenty-four guineas the second, 

 twelve guineas the third ; and, if a fourth, six g\uneas ; the fees pay- 

 able (piarterly, in advance. These terms are high; but, altogether, 

 the institution, proceeding on a practical basis, is calculated to effect 

 much good. We should wish, however, that it was in the power of 

 the directors to place the institution within the reach of mechanics; 

 as, with great liberality, they have thrown theschool open to amateurs 

 at three guineas per (juarter. We think that it is well worthy of the 

 attention of the directors to make instruction in the steam-engine a 

 part of the course of their naval pupils, and also to afford facilities for 

 the instruction of steam-boat engineers, which would be a more 

 efficient measure for preventing accidents, than -any quack laws and 

 jobbing superintendents. 



