THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[January, 



■well, the bottom of which was only 12 feet G inches diameter, and as direct 

 jiroof had been obtained by borings, that below the '-'A feet reached in the 

 well, there was a constant recurrence of large springs, giving evidence that 

 the water rapidly increased with the depth, which when 80 feet were obtain- 

 ed, became so prodigiously plentiful as to set all temporarj' meaiis of over- 

 coming it at defiance, and precluded all possibility of having recourse to it for 

 the mere purposes of an experiment, I thought it quite unnecessary to seek 

 further proof that a sufficient supply for all requisite purposes might with 

 facility be obtained. 



It would be premature to give, in the present stage of the jjrocecdings, a 

 detailed account of the arrangements I propose making, for augmenting the 

 quantity to an adequate extent, and it may be sufficient to state here //laf I 

 fiace not the slii/Atest doubt, that by sinking a deep well, and extending tun- 

 nels, or drifts in the proper direction from its bottom, the necessary supptij 

 will be fully accoinplisJiUd. 



Being also convinced that the water filtering through the chalk might be 

 considered as entirely divested of all impurities, held in mechanical snspen- 

 suon, of which, indeed, there was abuudant ocular demonstration, (as it was 

 30 beautifully transparent as to ailuiit of the bottom of the well being seen 

 v,hen the water was upwards of thirty feet deep,) I at once turned ray atten- 

 tion to the best means of conveying it to London. 



The principal difficulty which intervenes is the ridge formed by the escarp- 

 ment at the outcrop of the plastic and London clays, which Mr. Telford in 

 his proposal to bring the water of the A'erulam stream to London, had con- 

 templated perforating by a tunnel three and a-balf miles in length. My con- 

 nexion with the Loiiilon and liinniugham Railway has placed me in posses- 

 sion of facts which convince me that at the level at which Mr. Telford would 

 have traversed some of the beds of the chalk, and the whole of the plastic 

 clay, he would have met with ver\- great difficulty, in consequence of water. 

 For this reason, I propose, on leaving the Colne valley, that before entering 

 the ridge which sejiarates it from the district draining into the lirent, the water 

 should be forced to a height of fifty feet above its original level, at which 

 elevation we get rid of the difficulties of the plastic clay, as wc only traverse 

 ((uite its upper extremity, where no water has yet accumulated. The length 

 of the tunnel is also considerably reduced. 



I have preferred adopting a Line which is materially shorter than Mr. Tel- 

 ford's, as. with the exception of the said tunnel 2V miles in length, no diffi- 

 culty of any kind is encountered. Immediately on the water re-issuing into 

 the open air on the side of Brockley Hill, I propose forming a reservoir to 

 contain three days' supply of water, w ith a sufficient head to admit of a main 

 being laid hence, and conveyed, (in order to avoid all opposition from land- 

 owners,) from the town of Edgware to Oxford Street, along the side of the 

 road itself ; thereby also faciUtating the laying of the main, and rendering all 

 the works of any magnitude, as earthwork, aqueducts, &c. unnecessarj*. The 

 level of the resenoir will lastly be such, that the highest service can be given ; 

 and indeed a part of the town, which none of the present companies can sup- 

 jjly, will be included within its range. 



I trust I have now said enough to convince an unbiassed person that there 

 exists no difficulty, l)oth in obtaining a supply of good water from the Springs 

 of the Chalk, near \\'atford, and in conveying it thence to London. I must, 

 however, impress you here with the necessity of enforcing my arguments, 

 with as ninnerous a body of facts as can be collected ; and I would therefore 

 recommend that, previously to the meeting of Parliament, I should be autho- 

 rised to collect such information respecting the quantity, nature and q\iality 

 of the wells in every part of the chalk circle which surrounds London, as will 

 bear practically on the subject. This might then be embodied in a second 

 Iiart or appendix to this Report, to be submitted to those who, being unac- 

 quainted with geological phenomena, may consequently hesitate in adopting 

 views which others, already scientifically acquainted with the subject, will not 

 for a moment call in doubt. 



In concluding, I may be allowed to cast a retrospective glance at the ad- 

 vantages held out by the project I have been called upon to examine. These 

 then consist in its being proposed to use spring water, already naturally fil- 

 tered, in preference to that which has drained a portion of the earth's sur- 

 face ; in making use of that enormous reservoir which nature has supplied us 

 •>vith in the Chalk, and effecting this at a spot where no existing interests can 

 he injured ; and in the selection of such a situation as enables us to convey 

 the supply to London with facility and econoiiy. and at a sufficient elevation 

 to satisfy the demands of even the highest part of the metropolis. 

 I have the honour to be. Gentlemen, 



Your obedient servant, 



Robeut Stephenson. 



London, Bee. IC, 1846. 



A.SSI,STANT ENGINES UP INCLINED PLANES. 



[At the last Meeting of the London and Croydon Raihvay. the following 

 reports were read, respecting the use of assistant engines up inclined planes.] 



To the Directors of the London and Croydon Hailtcay, 

 Gentlemen — According to your instructions. I have written to the Liver- 

 pool and Manchester, the Grand Junction, and the London and Birmingham 

 Kailwavs, to ascertain whether the practice of assisting trains up inclined 

 planes by an engine at the rear exists on those lines, and whether it has ever 

 heen found to be atcended with danger or inconvenience. — I learn that on the 

 liverpool and Manchester H-iilw-iy, the system is in daily use, and that it has 



never been found to be attended with dangerous consequences : on the con- 

 trary, it is considered safer with a long train to assist up an inclined plane 

 by an engine behind the train rather than in front— On the Gr.ind .lunction 

 R.ailway, the a.ssistant engine is behind in assisting up short and steep in- 

 clines ; but elsewhere the assistant engine, if required fur heavy or late trains, 

 takes the lead. Hitherto, neither ineunvcnience nor danger has resulted from 

 (he practice, which is piuhibitcd except on inclined p'anes. — On the London 

 and Birmingham Ila Iway. pushing a train on the line is only allowed in cases 

 where the power cannot be applied in any other way. Your obedient servant 

 CiiAELKS H. Gregoev, Resident Engineer. 

 December 8th, 1840. 



To the Directors of the London and Croydon Ruiliea:i. 

 (ientlemen. — According to your instructions, I have this day tried an ex- 

 periment, in the presence of the Chairman, Deputy -Chairman, arid Mr. Haines, 

 for the purpose of determining practically the cflecl of the assistant engine on 

 the inclined yilanc at New Cross, anil the .actual amount of danger to be anti- 

 cipated from the sustained pressure of the assistant engine in the case of any 

 sudden stoppage of the train before it. With this view, a train w.is made up 

 of five loaden coal-wagons of a gross weight of .30J tons (« hich is ,-bout equal 

 to an ordinary passenger train). The Croydon engine was placed at the head 

 of this train, and drew it up the inclined plane, with the Herndes engine as- 

 sisting at the rear. — On the train acquiring a ve'ocity of 221 miles per hour, 

 the steam of the leading engine was suddenly shut off. The effect was in- 

 .stantaneously felt in the assistant engine, on which the whole weight of the 

 train seemed thrown back, causing a strong re-action, which reduced the ve- 

 locity of the train to \'> miles per hour, the steam being still acting with full 

 force in the assistant engine. The order was then given to stop the assistant 

 engine ; the steam was shut oil', and the brake screwed down, wlieii the engine 

 instantly separated from the train, and stopped in less than its own length. — 

 The same train was then taken up by the leading engine alone, and on at- 

 taining the same speed of 221 miles per hour, the steam was shut off. The 

 velocity of the train was reduced for the first furlong from 22! to 12 or 15 

 miles per hour, being nearly the same as in the previous case, when the as- 

 sistant engine was acting behind. The engine and train stopped in a distance 

 of7-32ndsof a mile, without the use of the brake. — The practical inference 

 from this experiment is valuable, as showing that there is a great deal of 

 unnecess.ary alarm existing as to the supposed danger of the assistant engine 

 on the inclined plane. — Kirst. Any stoppage of the train is instantly felt on 

 the assistant engine, w hich may be stopped before any serious result can arise 

 from its overrunning the train. — Secondly. The effect of any sudden stoppage 

 of the train is to cause such a sudden re-action on the assistant engine that 

 for the first furlong alterwards it appears to communicate scarcely any im- 

 pulse to the train, the velocity of the train after the steam is shut off' in the 

 leading engine being nearly the same, w tb or without the action of the as- 

 sistant engine. — Thirdly. The retarding etleet of the inclined p!,ane is so great 

 that the least obstruction would be suflicient to stop the train in a very short 

 distance, even when the assistant engine is acting w ith full force. Your most 

 obedient servant, 



Cn.\RLEs HuTTON GREGORY, Resident Engineer. 



It was stated at the meeting that Mr. M. Ricardo, of Brighton, had con- 

 structed a model of a machine which appeared likely to be ot use not only in 

 such cases as w ere now more particularly referre J to, but in cases of collision. 

 — The model was here exhibited. It consisted of a strong frame-work, some- 

 what similar to the frame-work of a goods-truck, the area being filled with 

 powerful springs, so arranged as to collapse upon the application of a strong 

 impinging force, the effect of the blow being thus of course broken. — A small 

 experimental railway has been constructed at New Cross staticm, for the pur- 

 pose of testing, as far as a model could test, the efficiency of the invention. 



THE ORIENTAL STEAMER. 



Abstract ot the Log of the Peninsular and Orietital Strain Navigation Com- 

 pany's Steamer Oriental, John Say, Commander, on her second voyage 

 from England to Alexandria and back. 



Steamed, out, 2.885 miles, in 317 hours 40 minutes. 

 — home, 2,880 miles, in 314 hours 35 minutes. 



Total distance, 5,765 miles, in G32 hours 15 minutes. 



[■"almouth to Gibraltar, v._ , 



itc of speed, 1 1 knots per hour. 



Lowest .iverage rate of speed from Falmouth to Gibraltar, violent gales, 

 "i knots per hours. Highest .tverage rate 



