35G 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



[NOVBMBBR, 



Hon much more by a enrface brokeo up in all its parts. I believe in all 

 these points tlie prevalent taete in English architecture has the advantage 

 ia purity. It is no part of my object to attempt any comparison in point 

 of positive excellence. 



SEWERS OF WESTMINSTER AND PART OF MIDDLESEX. 



AVERAGE DISCHARGE OF SEWAGE.* 



Stairs' Office, October ^rj, 1845. 



In compliance with the Order of Court of 6th October, 184S, to report 

 " on the average discharge of sewage from the foJlowing outlets, viz. — 

 Church-lane and Smith-street, Chelsea ; Ranelagh, King's Scholars' Pond, 

 Crosvenor, Horseferry-road, Wood-street. King-street, Norlhamberland- 

 street, Durham-yard, Norfolk-street, and Essex-street, under ordinary and 

 *;xtraordinary circumstances," — I beg leave to present the accompanying 

 tabulated results of some experiments at the above-mentioned outlets, made 

 during the months of May, June, and July of the last year. 



The Plan of the district of this Coramission shows the comparative sur- 

 face drained by each of the above outlets ; their total area being about 7000 

 acres, of which nearly one-half may be considered urban. As the obser- 

 vations were made during fine weather, tlte results will only indicate the 

 discharge under ordinary circumstances. 



The general conclusions deducible from these experiments are,— 



1st. — That the mean discharge per acre, taking the whole surface 

 drained, urban and suburban, is about 25G cubic feet in twenty-fonr hours. 



2nd. — Considering the dryness of the weatherduring these observations, 

 the above quantity of sewage may be assumed as solely derived from arti- 

 ficial sources and due to house drainage ; supposing therefore the entire 

 surface to be urban, we have 540 cubic feet as the mean daily discharge 

 per acre. If, however, the average be taken of the first eight outlets, viz., 

 from Essex-street to Grosvenor-wharf inclusive, which drain a surface 

 wholly urban, the result is 1200 cubic feet per acre in the twenty-fonr 

 hours. This excess may be attributed to the number of manufactories and 

 the densely populated nature of the locality drained ; but, as indicative of 

 the general amount of sewage due to ordinary urban districts, the former 

 ought perhaps to be considered the fairer average. 



3rd. — Assuming, (as regards the relative proportion of urban and sub- 

 urban.) the district to which the accompanying observations refer to be a 

 fair type of that included within the whole of the Metropolitan Commis- 

 sions of Sewers, and taking the extent of tlie active jurisdictions of those 

 on the North side of the River Thames at 43 square miles, and the juris- 

 diction of the Surrey Commission at 15 square miles, the ordinary daily 

 amount of sewage discharged into the river on the North side would be 

 7,045,120 cubic feet, and on the South side 2,457,000 cubic feet, making a 

 total of 9,502,720 cubic feet, or a quantity equivalent to a surface of more 

 than 30 acres in extent and 6 feet in depth. 



(Signed) George Hawkins, Assistant Surveyor. 



Discharge from the Principal Outlets in the Westminster Commission of 



Sewers, being the Mean of Seven Obserrations taken during the Summer 



«/1844. 



Asphalted Brickwork. — The New River Company, under the super 

 intendence of W. S. Mylne, Esq., their engineer, are constructing a large 

 reservoir upon Highgate-hill ; the interior will be built of Sei/ssel asphil teil 

 brickwork, for the purpose of rendering the reservoir perfectly water-tight. 

 It is expected that this important work will be completed in about two 

 months' time. Messrs. Mansfield and Sons are the contractors. 



PROBLEMS IN SURVEYING. 



Sir, — The last number of your JournEil has just been put into my hands, 

 in nhich I see some Trigonometrical Problems by '■ Professor Oliver 

 Byrne, Mathematician." 



The principle from which the professor deduces the solstion was first 

 employed by me for that purpose in 1829, when all the cases of the pro- 

 blem were resolved exactly in the same manner as in your Journal, toge- 

 ther with the several cases of the kindred problem proposed by Mr. "Town- 

 ley, and which is so well known to marine surveyors for its great use in 

 fixing the positions of places at sea. The problems, with their solutions, 

 appeared in one of the earliest numbers of " Colburn's United Service 

 Journal,"' hut, being without signature, the author's name was unknowD 

 to the public. 



The problem was proposed to me by Capt. John Hobbs, of the Royal 

 Engineers, while he was snperintendiug the Ordnance Survey in Ayrshire 

 in 1820-1. The solution I then gave was geometrical, with which Capt, 

 Hobbs was so well pleased that he gave me an order for ten pounds on 

 the Ayr Bank, and at the same time recommended me to the consideration 

 of Col. Coleby, if I should ever happen to visit London, which at that time 

 was very far fmni my tiionghts. 



I was in the employment of Messrs. Cottam and Hallen when I drew 

 up the Analytical Solution for Mr. Colburn's Journal. My mind was then 

 directed to the subject by an obscure and neglected proposition in Emer- 

 son's Trigonometry, from which I was aware that a very concise method 

 of finding the angles could be derived without the intervention of the given 

 distance, and thence the several required distances became known wtlh 

 very little trouble. The same principle was afterwards adopted by Dr. O. 

 Gregory, in the third volume of Dr. Hutton's Course ; but, without any 

 acknowledgment of the source from whence it was obtained, it has since 

 been adopted under similar circumstances by several individuals who have 

 written on Surveying and Engineering, amongst whom are Castles, Baitrn, 

 and lit/rne, — the last of whom having i>roduced the article referred to in 

 your Journal. Now, you will understand that I do not mean to quarrel 

 with Mr. Byrne for what he has done, I only regret that he has not car- 

 ried the subject a little farther, and rendered the solution more complete, 

 for it is a most beautiful andjimportant problem when taken in all its gene- 

 rality. 



I am, Sir, yours truly, 



William Turnecu.. 



NOTE ON DREDGE'S SUSPENSION BRIDGES. 



We have just received a letter from Mr. Dredge from which we make 

 the following extract. 



" Mill you please alter a little expression in the reply to Mr. Bashforth 

 which will appear next month ; it is this — instead of printing 'The oblique 

 direction of the suspending rods ijecessarily involves. Sec.,' put ' The xxiri/- 

 ing obliquity of the suspending rods, &c.' For it is the variation in the 

 obliquity which causes the intricacy of investigation." 



Mr. Dredge requests us also to state that Mr. Turnbull, of whom he had 

 not heard for several years, has sent him a letter stating that his Treatise 

 on Suspension Bridges " was the production of five days, and that too under 

 severe illness when he was obliged to be propped up iu bed." This cir- 

 cumstance does not prove his treatise accurate, but it certainly accounts 

 satisfactorily for its inaccuracy. We regret to say, also, that Mr. Turn- 

 buU's present letter appears to have been written under most painfol cir- 

 cumstances ; they are of too private a nature to be made public, but we 

 can assure the reader that they entirely preclude any further strictures on 

 Mr. TurnbuU's past productions. 



MOTION OF LOCOMOTIVE ENGINES. 



Sir, — You say in your note appended to my last communication that my 

 experiment is not analogous to the case in point, because it was a mus- 

 cular force from without, and that if the experiment is repeated while 

 sitting in the carriage, what then will be the result ! Most assuredly, it 

 will then move as a Locomotive engine, urged by steam ; and it is a very 

 beautiful illustration of the truth of my conclusions, that in all such cases 

 of — and opposite reaction, which occasion opposite, but not = effects, that 

 motion is produced in tlie direction of the greatest etl'ect. Suppose, a per- 

 son sitting in a Manuniotive carriage pulls on a crank with a certain force, 

 a corresponding reaction must take place on the body of the carriage, for 

 if not the experimenter would be drawn to the crank, and not the crank in 

 the direction towards him. This = reaction has, as before observed, either 

 a greater or less leverage from the point of contact of the wheel and rail, 

 as the position of the crank in its revolution niair determine, and the 

 greater eii'ect of the two forces causes the motion of the Manumotive car- 

 riage. On referring to the diagram in my first letter, (page 293), and for 

 the action of the steam on the piston, and the reaction on the cylinder 

 cover, substituting the muscular action, and reaction used in this case, 

 good reason will be seen why the = and opposite internal forces cause (on 



