T. Hawksley, Esq. taken exactly in the middle of the lake, both as regards length and breadth, nearly opposite the Humane Society's house. 7 March 1860. 323. Sir John Shelley.] Are the Committee to understand you that that is the state in which the water is now, and that when it has gone through your process of filtration the effect will be to produce that water which is supplied by water companies at present to drink?--Yes, as nearly as may be; I do not say exactly, because the sources are not precisely the same. 324. After the expense has been incurred of your filtration system, what will be gained will be the difference between the water in the state in which it is now before the Committee and the state of the water as it is supplied by the water companies? Yes, as nearly as may be; I think the water contains from 18 to 20 grains of inorganic matter in a gallon, and this contains of the same matter 22-24 grains. 325. Taking the water in that state, and supposing we were in the months of June, July and August, with a different temperature, do you consider that the water would produce such a stench as to be perceptible, and to be inconvenient to the neighbourhood?-No, it would not; I may add, if you will permit me, that it never has done that; at the same time, a stench has come from the Serpentine there is no doubt, but the water has not produced that stench; not the natural water of the Serpentine. 326. What has produced the stench-The influx of water from the sewers. 327. Which is about three times a year, if I understand aright, from your evidence-Yes; there was a large quantity of it last summer; at one particular time, the day when a great thunder-storm was, if I recollect on a Sunday, a large portion of sewage water was poured into the lake on that day; on previous occasions there had been sewage water poured in, and, as I mentioned before, in particular states of the atmosphere, near all rivers in which the confervæ grow, there is always what is called the marsh odour, or the riverine odour, as it is sometimes called. 328. You stated, did you not, that that smell might be observed at times in lakes in gentlemen's parks?—Yes; in natural lakes and by the sides of rivers; you find the same thing in particular states of the atmosphere, with a falling barometer, for instance, after a sultry day, in what is called muggy weather, you perceive it in the evening along the shores or near rivers. 329. You observe it irrespective of any question of sewage at all?-Perfectly so. 330. How far does the overflow of the sewage, which, according to your evidence, takes place upon an average three times a year, affect the stench at the lower end of the Serpentine-I do not think that it has very sensibly affected it, or at least, not of late years; when the water was running into it day by day, as a matter of course, it was affected. 331, Reverting to that water which you have produced, putting aside all question of the sewage, what you propose to do by your process of filtration is, to bring the water in the bottle which you have produced, and which you believe to be tolerably pure, to such a state, that it might be supplied, as the waterworks companies do at present, for drinking purposes?-No; I do not say so, because there are many reasons why you would not supply that water for drinking. As a matter of course, you would not supply for drinking that water in which you allow persons to bathe. 332. I meant to say that after your filtration has taken place, what you would gain is the difference in the quality of the water between that which you now produce, and that which is delivered by the water companies to the metropolis? Within the limits I have mentioned; I am obliged of course, to state that. Here is a bottle of water (producing the same), which has come up this morning from the Leicester waterworks after filtration, where it remains in a stagnant pond, in a space twice as large as the Serpentine; you see the difference between the two waters. Now, if I were, in this room, to pass this sample of water from the Serpentine, through two folds of blotting paper, you would find it brought into the state in which you see that Leicester water is. 333. Putting aside all question as to the Serpentine water being intended to be supplied for drinking purposes, are the Committee to understand that you consider that the advantage gained in producing water of the quality of this sample from Leicester, as against the quality of the water from the Serpentine, is worth the expenditure which you are incurring in this filtration system ?—Yes, I think it is; but I will tell the Committee why I think it is so: I think it is so, because 7 March 1860. because there is a popular feeling and impression in favour of taking out that T. Hawksley, Esq. colouring matter, which you observe in the summer in the Serpentine water;' but it would certainly look nicer, and be more agreeable to bathers and persons walking along the banks. Beyond that, I should not think it was worth while to expend even this sum of money upon it. 334. You stated, did you not, the other day, that no doubt the proper course would be to pump fresh water in if such could be done?-No doubt it would; because the vulgar are quite unlearned upon these matters; necessarily so, and they ever will be. 335. Then if the object is to follow the popular wish, that popular wish, putting aside all questions of science, would be equally gained by a supply of fresh water, as by leaving the water in the state in which you see it in the unfiltered sample, or bringing it to the condition of this water from Leicester ?—If you can bring in 2,000,000 gallons a day, that supply would meet that popular wish, except in so far as the cost of doing that would perhaps make the project unpopular amongst persons who have to pay for it, and who do not enjoy the advantages of it. 336. Supposing, for the moment, that it were hereafter to appear to this Committee, that with regard to the question of expense, the expenditure in the one case (taking the whole subject into consideration) would be as great as in the other; and that there would therefore be no extra expense in pumping fresh water into the Serpentine, then putting aside any chemical or scientific question, would the popular view be equally met by that plan, as by bringing the water in the Serpentine into the condition in which it appears in this filtered bottle?— Yes; I turned my attention, in the first instance, to the possibility of doing that, but I found that it was impossible; and then I turned my attention to the mode of purifying the water without encountering that difficulty. 337. You stated, did you not, that when the Chief Commissioner, Mr. Fitzroy, sent for you, the only question that you had to consider was the question of the purity of the water?-Yes; of course we had a discussion upon it, so that I became conversant with Mr. Fitzroy's views, and I saw him several times on the subject. 338. I think you stated that most, if not all, the various projects with regard to this supply of water or cleansing the Serpentine had been brought to your notice-No; what were brought to my notice were the papers of which a list was given to me in the letter which accompanied them. 339. I understand that these had been officially brought before you?—Yes, and no other; but still I have to explain with regard to this matter, that these letters came accompanied by a letter from the Secretary, in which, under an understanding which you will find in that letter, he requested me to report upon them; now I had had a totally different arrangement with Mr. Fitzroy, and the consequence was, that, perceiving it to be a mistake, I went to Mr. Fitzroy and asked him what was meant by it; Mr. Fitzroy said, "No, I do not want you to report upon these papers; I directed them to be sent to you, but I only wanted you to have them for your own information ;" and therefore the Committee will find that my report does not touch upon those papers at all, excepting in an incidental way as to some questions of cost. 340. In your distinguished position as a hydraulic engineer, of course all questions with regard to the supply of fresh water to or cleansing the Serpentine must have been brought to your notice at various times, and I think you stated in your evidence that your attention had been very much given to the subject?—I think that every means of supplying the Serpentine fell under my notice, but no special means was brought before me; when I say every means, I mean that every possible source was considered by me spontaneously, but no special plan was brought before me by any one. 341. Then the reason for you putting the public to this expense, little or great, of bringing the water from the foul to the purified state, as represented by these two samples before the Committee, has been that you do not imagine that any scheme has ever been proposed, or is possible, for supplying the Serpentine with fresh water?--As to the possibility I would not say, because I am quite sure that it is possible; you may go to the higher reaches of the Thames, and you may bring in a supply of fresh water from that source; or you may go to the lower reaches of the Colne, and you may do some other things which, within the limits of expense that Mr. Fitzroy represented to me, would be quite impossible; you might get T. Hawksley, Esq. 7 March 1860. water to a limited extent from the chalk by sinking a well, but that would only be to a very limited extent, and the expense would be great as compared with the quantity of water which would be yielded. 342. Have you ever gone in detail into the expense of the propositions that have been made with regard to the supply of fresh water to the Serpentine? -No. 343. Have you not considered that question which was brought officially before the Chief Commissioner, with regard to the supply of water from the engine in Duck Island ?—No, that never was brought before me in any way or shape. 344, Have you never heard of it?-I had never heard of it, nor did I know anything about it till the appearance of the final communication as exhibited in Messrs. Easton and Amos's correspondence, of which the Chief Commissioner, Mr. Fitzroy sent me a copy; but that was after I had made my report. 345. You never were at all aware that the cleansing of the Saint James's Park water was the other part of the whole scheme?-I never heard of that until the correspondence was published. 346. Then it being entirely new to your mind all question of the possibility of a supply of fresh water from Duck Island, your evidence and your report goes entirely upon the supposition that there is no other scheme than those which you have alluded to, of bringing the water very high up from the Thames, or otherwise? Certainly not, but it is based upon the supposition that there is no other practicable scheme. 347. I said possible scheme; a scheme that could be carried out in your opinion?-I think that there is no scheme of that kind which can be carried out now, for I am perfectly certain that there is not the quantity of water in Duck Island to supply the Serpentine, and its quality is such as to render it perfectly inadmissible; I have considered that subject, not as connected with the Duck Island, but with regard to the quality of the water yielded by the superficial sands in London; and that did not escape my attention when I was considering the subject as to the practicability of getting water from the sands in London, and I came to the conclusion in a moment that we could not look to that source; it presented itself to my mind, but I dismissed it as a perfectly infeasible thing, and I never heard of any proposition of Messrs. Easton and Amos's in any part of the subject. 348. You were not aware whether the new lake in St. James's Park was filled from the well in Duck Island ?-I knew that perfectly well. 349. When you gave your opinion that there was not a sufficient supply, did you go systematically, as an engineer would do, who was about to give a report upon the subject, and inquire into the actual quantity of water daily produced by that well?-No; because the actual quantity of water produced by that well has never been ascertained, and it can only be ascertained under an order from this Committee. I should be very glad to do it, if the Committee will give me leave to pump that well, and I will undertake to pump all the water out of it, and out of all the gravel in the neighbourhood. 350. Are you aware of the quantity at present being produced daily from that well?-No; but you can always pump a large quantity for a short time. This is a thing with which I have had a great deal to do all my life; and I say that you may always pump a large quantity of accumulated water out of gravel; but the question is, what is its yield into the gravel after the accumulation is removed. If I have a barrel, I can draw from the tap at the bottom a large quantity of auy liquid that it contains, for a short time, although I only put a small quantity into it; the result will be that finally I shall only get that small quantity out of it; and that is precisely what takes place in the gravels here and elsewhere. 351. That is to say, that supposing for a short time a collection of water has taken place in any particular substratum, you may for a short time get an enormous quantity out of it-For two or three months continuous pumping, you might. 352. Perhaps even, at the outside, you may say six months?-No; I do not think that there is any place in London to which adequate power was applied, if there was no re-infiltration into it, from which you could draw for six continuous months 2,000,000 gallons of water a day. 353. What do you mean by no continuous infiltration into it?-I mean that the water which is pumped shall not be restored, but shall be ascertained to have run away away out of the district, and not return to the source from which the well derives T. Hawksley, Esq. its supply. 354. Supposing it were capable of proof to this Committee that not for three 7 March 1860. months, or for six months, or for twelve months, but for more than twelve months, there has been a greater amount of water daily pumped out of that well; that would rather shake your opinion, would it not?-Not in the least, unless I knew it was also pumped away. 355. Do you mean poured right down into the Thames?—Yes. 356. Would that be a large amount?-Of course the words "a large amount" are comparative; some persons might consider 400,000 or 500,000 gallons a day a large amount; but we are speaking with regard to the purification of the Serpentine. 357. We are speaking with regard also to the supply of fresh water to the Serpentine-Yes; but allow me to state this, that what I understand as to the supply of fresh water, is a supply of purified water of any kind; what I wish to present to the Committee is this, that unless the Serpentine is in the hot weather completely emptied every month; no matter what kind of water you put in it, this very same vegetation will occur; but it will take 2,000,000 gallons a day. 358. You propose to put 2,000,000 gallons a day into the Serpentine ?—Yes. 359. Is that the least that would be required?—Yes, quite the least. 360. Then, supposing it could be shown to this Committee that 2,000,000 gallons a day of water which has purified itself by natural filtration, could be supplied, then, according to your view that it would be more popular to supply fresh water in that quantity than filtration water, you would, under these circumstances, be for pumping fresh water instead of filtered water?-The cost and the quality being equal, I would certainly do that; but I have also had the Duck Island water analysed with reference to the Serpentine, both taken the same day, and both taken by Dr. Odling, and the organic matter in the Duck Island water is 8 grains, and the saline matter is 76 grains, and the two together are 84 grains; and the hardness of the water is 30 degrees as against 11 degrees in the Serpentine. 361. Do you give that as a certain analysis made by Dr. Odling?—Yes; by Dr. Odling, who will be here to give evidence before this Committee. 362. Mr. Locke.] Will you repeat the analysis of the Serpentine at the same time?-Organic matter, 2'96 grains; saline matter, 22:24 grains. 363. Sir John Shelley.] Do you happen to know whereabouts that water was analysed from?—It was taken from the well itself, by letting down a vessel into the pump trough. 364. Then, are the Committee to understand by that, that the water being pumped up at this moment at Duck Island, is actually more impure than the water at this moment in the Serpentine ?-Decidedly so. 365. That you are certain of?-Dr. Odling is here to give evidence on the subject; he is a very able analyst. I was not present, because I kept myself quite apart for my own subject; but these analyses were taken yesterday, the engine, as I understand, being then at work. 366. Is this to be accounted for by what you stated the other day, that the water in Duck Island is contaminated by a vast number of sewers passing through it below the tidal level; tidal lock sewers, and cesspools ?--Yes. 367. I think you stated, that they were cesspools in Belgravia ?—Yes, all about Tothill Fields and Great George-street, and there are large numbers in Belgravia. 368. Will you have the kindness to mention to the Committee two or three of those cesspools in Belgravia, to which you have referred?—I will bring the Committee a list of some of them; but if I am rightly informed, there are far more than 1,000 in Belgravia. I do not know where Belgravia proper extends to exactly; but there are that number in the district which I have mentioned. 369. With regard to this filtration system; what is the area of your four filterbeds? They are each 100 feet by 60 feet, about 24,000 square feet in all; there are some little crnamental corners taken off. 370. What medium of filtration have you; what sand do you use, and how fine is it? It is Thames sand. 371. Is it very fine-No; that is the worst filtering medium you can have for a purpose of this kind. The sand should be coarse; it is particularly prescribed in my specification, that it shall not be a fine sand; fine sand clogs almost T. Hawksley, Esq. immediately, and does no good at all; in all my specifications for towns, I always object to fine sand; the bottle of water that I have produced from the Leicester waterworks is filtered through coarse sand. 7 March 1860. 372. With regard to the water in the Serpentine before filtration, how is it, as to impurity, compared with the water of the Thames, above Teddington Lock, before it is filtered by the water companies ?-The water in the Thames varies a good deal. 373. Above Teddington Lock, for instance?—I should think there are possibly three or four degrees of difference between them. 374. In favour of which-In favour of the Thames, excepting as to the organic matter. 375. What difference is there as to that?-I think the organic matter in the Thames in summer is usually, in fact I know it to be usually about two grains in a gallon. 376. As against how much in the Serpentine?-2.96 grains now, and last summer it was a little less; but then that might be accidental. 377. What depth of water will there be on the filtering beds and the filtering medium-Two feet six inches. 378. Do you call that shallow or deep, as compared with other filtering beds? -It is about six inches deeper than is generally put upon them. 379. Is there any fear of these confervæ increasing in hot weather, in that case?-Confervæ will grow upon the surface, but they are very easily removed. I remove them from the filter beds by a very simple process. I get a line very much like a sash-cord line; that I let down into the water, and I just draw the line along, and it fetches them all off immediately 380. You stated, did you not, that some of these confervæ, at Nottingham, had increased as much as 18 feet in 48 hours; will anything like that occur in this Serpentine?—No; I was bringing under the notice of the Committee the very remarkable circumstance that confervæ grow most rapidly in that water which has never seen the day, upon its first coming to the light; and it is a wellknown thing; and, in consequence, we are obliged to arch over all our reservoirs which we use permanently, for in the course of a very few days they become quite loaded with confervæ, and naviculæ, and all the vegetation of the lowest order: and we are arching them over in all parts of the kingdom to prevent that effect being produced. 381. In this case, in hot weather you do not expect anything of that sort to occur, to that extent at any rate?-No. 382. To any great extent?-Yes, it will occur very considerably, and the clearer the water the more that will be the case; this water from Leicester comes into a central tank which is not yet covered over; that central tank, I think, is about 60 feet diameter, and there flow through it various quantities of water, from 1,000,000 to 2,000,000 gallons a day; and yet, bright and pure as this water is, in the course of a fortnight in the hot weather of summer you have strings of confervæ coming up from the bottom five or six feet long. 383. I understand you that all the filter beds will be at work at the same time? -Yes; that is in the hot weather of summer; at other periods of the year that will not be the case. 384. How soon after you first turn the water on to the filter-beds, would you have to clean them in summer?-In the hottest weather of summer, you may have, possibly, for a very short time to clean out once a week. 385. On the average in summer, how often would it be?-On the average in summer you would clean them all round, I think, once in three weeks. 386. Do you think that that will be enough for filter-beds of that size?—Yes; you must understand (and I wish to be very express upon that) that there is no clay, or mud, or dirt in this water at all; I have not that to choke the filters; it is nothing whatever but this fibrous organic matter, and the small naviculæ desmidiæ and diatomacea that I have to remove. 387. Under those circumstances, what is the quantity of water per square foot that would pass through on the first day of pouring on to the filter-beds?—The total quantity of 2,000,000 gallons a day, divided by 24,000 feet, or thereabouts. 388. Is that so?-Certainly. 389. That is to say, the water will pass as fast through on the last day as on the first-No; that is the quantity that the engine pumps, and the first day the engine |