64 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL, 



fFEBRfABi', 



which they are exposed. C'iles the instance of the beam of a steam- 

 engine vibrating continually wiiliout suflering any injury, as au inslanceof 

 iron not being allected by continual vibration ; and mentions, in favour of 

 its being so affected, the fact of a gun, employed to break pig iron across, 

 dropping in two after a series of years. Considers the only security for 

 good work is, to hold the makers responsible for it. Has found great va- 

 riations in bars of similar metal. Thinks that the breaking Height of a 

 gmall bar is no index to the breaking weight of a large casting. 



Joseph Cubilt, Esq., Civil Engineer. — Is at present constrncting the Great 

 Northern Railway. Prefers a mixture of Scotch and Welch or Staffordshire 

 and Scotch irons for large castings, as mixtures are stronger than single 

 irons, lielieves cold blast iron to be stronger than hot blast iron. Would 

 make tlie breaking weight of a girder six times the greatest load. Proves 

 a girder nith three times the greatest load likely to come upon it, or half 

 the breaking weight. Proves girders either with the hydraulic press or 

 with dead weight ; strikes them while the weight is on with a large wooden 

 mallet. Does not consider a girder would bear so much weight if applied 

 on one of the flanges as if applied at the top; prefers loading the girder at 

 the top if possible. Considers the proportions he adopts as sufficient to 

 compensate for the torsion. Has often tested girders with the load on the 

 bottom flange. Has two girders for each line of way, and supports the 

 rails on wooden bearers. Considers any elastic substance between the rails 

 and cast iron girders of advantage in preventing shocks. Does not con- 

 sider it likely that girders would increase in deflection after a length of 

 time. Would not like a girder of 40 feet span to deflect more than J 

 inch ; those he is putting up will not deflect half that amount. Observes 

 the deflections of girders \-vhen testing them. Adopts Mr. llodgkinson's 

 form of girder, but makes the top flange rather larger, to give lateral stiff- 

 ness. Would not like to go beyond 50 feet for the length of simple cast 

 iron girders. Beyond that span would adopt timber, wrought iron, or the 

 bowstring bridge. Has crossed spans of 100 feet by timber bridges and by 

 wrought iron tubes. Considers a bowstring girder with a cast iron bow 

 and wrought iron tie a very good combination of wrought and cast iron. 

 Would prefer wrought iron or timber. Would use an arch of cast iron if 

 not limited with respect to expense or levels. Does not consider the im- 

 pact and vibration to which railway bridges are suljjected sufticient to injure 

 the joints and rivets. In wrought iron hollow girders take the depth at 

 ■jJj th of the span. Subjects them to the same proof that he does cast 

 iron. Does not observe that they acquire any permanent set. Has put 

 some up at Doncaster of 70 feet span. Has found no difference between 

 the effect produced by a weight at rest on a girder and that due to the 

 weight moving at a velocity over it. Considers the greatest weights run- 

 ning on railways to be engines, they weigh 2j and 30 tons. Something 

 more than half the weight of the engine is on the driving wheels. Has 

 preferred for a viaduct near Welwyn, on the Great Northern Railway, brick 

 arches to iron girders. Approves of the wrought iron girders used in the 

 large spans on the Blackwall Railway. If kept painted they will last for a 

 long time ; in some cases, to prevent torsion, a cross piece of cast iron be- 

 tween the tops of two girders is advantageous. 



SUPPLY OF WATER TO THE .METROPOLIS. 



We promised to give an account of the different projects which 

 are now before the public for the supply tif the metropolis with 

 water, of a better quality and in larger qiiantities tlian the supply 

 now given. There are five schemes — namely, 1st. The Henley; 

 2nd. The Mapledurham; 3rd. The \Vatford; 4th. The AVandle; 

 and, oth. The Kingston. 



^\'itll regard to the Henley and Mapledurham schemes, there 

 has just been issued a very able report made by Mr. James AValker, 

 the eminent engineer, and 'Slw Stephen M'illiam Leach, the en- 

 gineer and surveyor to the Corporation of the City of London; 

 and another valuable report on the ^Vatford sclieme has just been 

 made by Mr. S. C. Homershani, the engineer to the Watford Com- 

 pany. 



It is not our intention to go into the (juestion as to whether the 

 supply ought to lie left to private enterprise or to commissioners; 

 but we must now say that generally we are advocates for the for- 

 mer, and have great aversion to public commissions — particularly 

 if we are to have such a board as is proposed to be constituted by 

 the Henley Bill, than which we cannot conceive one more objec- 

 tionable could possibly be formed. The Commissioners are to 

 consist of persons to be elected, yearly, by the ratepayers of the 

 several Unions of the metropolis, one for each Union; and tliese 

 Commissioners are to elect a Commission of seven persons, who 

 are to take the entire management of the concern, and are to 

 receive for their labours the sum of i! 7,700 per annum between 

 them, out of the water rates. By this mode of election, we are to 

 have the metropolis constantly agitated for all the rated inhabit- 

 ants of the different Unions to muster together, and go through 



the farce of electing one Commisioner who is only to be a delegate 

 to elect another representative; and to this irresponsible Commis- 

 sion of seven persons, liable to vary every year, is to be entrusted 

 the outlay of two millions sterling." With regard to the amount 

 of the water rate, there appears to be no limit as to what it will 

 be; — first, the Commissioners will have the power of chargino- 

 three pounds per centum per annum on the annual rack rent of the 

 premises; and, in addition to the said maximum rate, the Com- 

 missioners are to have power to charge a proportionate part of 

 whatever sum they may be yearly liable to pay, wliether for inte- 

 rest or annuities upon moneys borrowed to pay for the purchasing 

 of the undertakings of the e,xisting water companies. 



We have made these remarks on the proposed Henley Act just 

 to show that the scheme can never be allowed to be carried out 

 under such an iU-advised Act. The Act, or rather the Bill, ap- 

 pears to have been drawn with a judgment very different to that 

 shown in the getting-up of the engineering department, which we 

 must say exhibits great labour, great talent, and great judgment. 



It appears to us that it will be far better for the House of Com- 

 mons to appoint a select Committee of the House, first, to examine 

 the different schemes that are proposed, without regard to the 

 Bills to be brought in for the regulation of the supply, and to 

 rejiort to the House which they consider is the best; and whether 

 the supply for the whole of the metropolis shall be confined to one 

 of the schemes, or whether it will not be advisable to have one for 

 the North of the Thames Westward of the City, another for the 

 City and Eastward, and another for tlie 'South of the River: by 

 thus dividing the supply, there wiU not be tliat great diversion of 

 the waters of the Thames from one portion of the river, as stated 

 in Messrs. Walker and Leach's report. 



Looking at the whole of the case impartially, we cannot see why 

 the enormous expenses of forming the New River cut, and all the 

 works connected with that Company, should be lost to the public, 

 a supply might be obtained from the New River head at Chadwell, 

 and the river Lea above Tottenham, quite equal to the supply to 

 be taken from the Thames at Henley or Mapledurham. To do 

 this, it will be necessary to obtain powers to divert the drainage 

 from the land and houses on each side of the cut, and prevent the 

 river from being contaminated. By adopting this scheme, one- 

 fourth of the supply of the metropolis might he confined to the 

 City and the Eastern district; and this would be done without 

 affecting the river Thames. — If this be granted, the consideration 

 will next be which of tlie three schemes, the Henley, the Maple- 

 durham, or the A\'atford, is the best for supplying the North- 

 ^Vestern district of the metropolis. — For the supply of the South- 

 ern side of the river Thames, we have the Kingston and Wandle 

 schemes. The former is put forward with the view of taking the 

 water from the Thames above Kingston, and beyond the influence 

 of the tide; and the latter proposes to take its supply from the 

 \Vandle just before the water is discharged into the river Thames; 

 and as the discharge is within the inHuence of the tide, the with- 

 drawal of the water from that [lart of the Thames (at \\'ands- 

 worth) cannot much affect the river, particularly if the supply be 

 confined to the Southern districts. 



Having said thus much, we shall now proceed to describe the 

 works of the several schemes. Tor the Henley and the Mapledur- 

 ham works, we cannot do better than give the valuable report ot 

 Mr. James Walker and Mr. Leach. 



No. I.— The Henley Works. 



The first in point of date is the Henley si-heme, notices for wliich 

 were given in the last session of parliament, but the bill was lost upon the 

 second reading in tlie Commons, after a debate of some length. As some 

 modifications have since been made we shall confine our description to the 

 plan now proposed and deposited. 



It commences by an aqueduct which branches off from the river 1 haiiies 

 near Mednunham Abbey, or about four miles below Henley. In its onirse 

 to London it is first liy an open canal 40 leet wide and 10 feet de. p, as far 

 as West Drayton ; thence 26 feet wide and 7 feet deep, to the river Brent; 

 and thence by two brick culveris, each 10 feet diameter, to West-end, 

 Hampstead. 



At Hambledon lock, which is about two miles below Henley, there is a 

 lift or rise of three feet six inches in the navigation. This lock is to be re. 

 moved, and one erected below Mednunham Abliey, the point of junction of 

 the aqueduct; so that the part of the river between the new lock and the 

 lock above Henley will form a nearly level pool or reservoir, five miles ia 

 length, and 88 feet above high water.* 



From Mednunham the course of tlie aqueduct curves round the foot of 

 the high ground, and approaches the Thames below Marlow, proceeds on to 



* By liigli water is always meant the high water of an average spring tide near Lou- 

 den, or Trinity standard. 



