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knowing that a patent was applied for not long since, for a method of draining land in a particular mannerinto the chalk, he thought it was hardly advisable to go to any great expense in taking water from the chalk, seeing that there was a danger of its being seriously contaminated. Laws might be passed to prevent the passage of drainage from houses into it, but if the level of the water under London were lowered to any great extent, it was quite possible to cause a flow back from the lower part of the river. For instance, there was said to be a fault in the chalk at Woolwich, and on a former occasion it was stated that the water supply at that place was frequently contaminated from that cause. There were also faults under the Thames, and if the water were lowered, there would be a flow back which might not be noticed for a considerable time, and eventually the whole body of the chalk water might become contaminated. There could be no doubt that the water was absorbed by the chalk beyond the amount absorbed in the first instance, for having placed a piece of chalk in water, and allowed it ample time for absorption, and then placed it in a vessel where it remained for some time, he found that not a particle of water ran out. His opinion was that water should be taken from the springs along the course of the river, whilst it was still pure. The water could be obtained at a depth of 30 or 40 feet all the way up the valley of each river, and it might be taken out of the chalk or other porous strata. It was shown that about half of the chalk district about London was covered with an impervious stratum, though the surface might be pervious, as it was reasonable to suppose it would be, because all the marsh land was flat, showing it was formed from sediment washed down from the hills, and being washed down gradually, it must necessarily be more or less porous, and contain a large quantity of water. With regard to swallow holes, it had been stated at a former meeting that there was a passage in Lincolnshire extending some miles under land, and out to sea.
Mr. JOSEPH QUICK, jun., said, referring to the statement of a previous speaker as to the condition of the Thames being at present so extremely low, that only 350 million gallons a day passed over Teddington Weir, he knew that information to be perfectly accurate. The question he wished to ask was, why advantage was not taken of the enormous quantity of water which flowed at other periods over the weir, and which, so far from being useful, was, on the contrary, a very serious detriment to navigation ? If those responsible for the water in the Thames stored up the winter floods, they might thereby regulate the flow throughout the year, and the condition of the river would be much improved, with advantage not only to those who took from it, but to those who lived on the banks. With regard to the case of the river Alyn, he had the misfortune to be opposed to Mr. Robinson before the Parliamentary Committee, but he certainly thought Mr. Lucas went a little too far in saying that the decision of the Committee formed any precedent for future cases, and that millowners were not to be compensated for water of which they were deprived by water companies or others. The circumstances were quite exceptional, but the Committee did not lay down any precedent to prevent millowners in future cases asking for water compensation.
Mr. W. B. KINSEY desired to corroborate Mr. Baldwin Latham's remarks with regard to the question of periods of drought. From his own investigations he found that ten years ago there was a drought, and again ten years before that, and there was the same drought now. He could also concur in what he said about the water flowing against the dip of the upper greensand. He was now carrying out works in the neighbourhood of Petersfield in the upper greensand, where the facts fully bore out what had been stated.
Mr. W. A. RICHARDSON said he had heard it stated with great surprise that the wells at Birkenhead were polluted. The water at Liverpool was taken from boreholes in the red sandstone, 450 to 460 feet in depth, and the water was frequently analysed, and was considered to be the best and purest in the kingdom.
Mr. LUCAS, with reference to the case of the river Alyn, produced a section showing the exact state of the case, and remarked that what he said in the paper was that it would affect similar cases. The section showed that the water flowing down the slanting strata sank into the limestone and ran a quarter of a mile underground in a course that was not known, and it was on that ground that the Committee refused compensation. Of course rivers which had no such underground course, would not be affected.
The CHAIRMAN then proposed a vote of thanks to the four gentlemen who had read the papers, which was carried unanimously, and the Conference adjourned for a short time.
THE ORIGIN OF WATER SUPPLY.
By G. J. SYMONS, F.R.S.
This title might possibly be supposed to imply a history of the past, but in this Health Exhibition, pace Old London, we deal chiefly with the present and with the future.
I know no better word than origin wherewith to describe the small portion of the great subject of water supply which I am permitted to discuss.
All water supply comes from the clouds, and it is with the products of the clouds as rain (including therein snow and hail) that I have to deal.
Perhaps before describing the general features of rainfall distribution, it may be permissible to explain (for the use of those who have never done it) how the fall of rain is measured. If we imagine a flat dish-a tea-tray, for instance-placed upon a lawn during rain, it is obvious that (subject to loss by splashing) that tray would at the end of the shower be covered by a layer of water of a depth approximately equal to that which fell upon all
portions of the lawn, and the depth of the water on it (say } inch) would be the depth of the rain fallen. Obviously, besides the loss by splashing, the water on this tray would soon evaporate and be lost, besides which the depth could not easily be accurately measured. For these reasons, some form of funnel is always used, so that the rain may be, as it were, trapped, prevented from splashing out, and from evaporation. In the gauge before you (a very inexpensive one) all known sources of error are guarded against, and, as the water collected by a 5-inch funnel is measured in a jar only 1} inch in diameter, it will at once be seen that its vertical depth is multiplied nearly tenfold, and, therefore, even th of an inch is easily measured.
There are other patterns specially adapted for observation on mountain tops, where they can only be visited once a month; others for observations during heavy thunderstorms, so as to obtain data needful for drainage questions ; others in which every shower that falls writes down its history, the instant of its commencement, its intensity during every minute, and the time of its termination ; but I must not stand between you and other papers with a discourse on the many interesting points which these gauges bring out.
During the last twenty-five years, I have done what I could towards establishing a complete system of recording the rainfall in this country. In early days the British Association for the Advancement of Science gave considerable help, but some ten years since they dropped it. Government have never given any help at all, and now the whole cost, or 99 per cent. of it, is borne by the observers themselves, a body which has now grown to the very large number of nearly 3000. I do not know the precise number, but there are every year new stations beginning, old ones stopping, and others interrupted ; yet for 1883, I have just had the pleasure of printing perfect records from 2433 stations, every record having been previously carefully examined and verified.
Hitherto, I have been so overworked, and my staff has been so small, that the discussion of the data falls behind the collection ; for this reason I cannot lay before you such data as I wish. However, the map on the wall is the one I drew many years ago, and which was inserted in the sixth report of the Rivers Pollution Commission. It is not perfect, but as it is tinted with increasing darkness for places with heavy annual falls of rain, it will at least show you the broad features of the distribution over the country,
I refrain from going into the subject in detail, desiring chiefly that you should realise the fact that large tracts of country have twice and even three times as much rain as others. If we descend to single stations, the differences are of course greater, e.g., in 1883, the rainfall at The Stye, in Cumberland, was 190:28 inches, and at Clacton-on-Sea, in Essex, it was only 18.71 inches ; that is to say, the one was more than ten times the other.
Here I should like to interpose a question as to public policy. There is often a great outcry if the water of one district is taken to another. Surely, while there is no relation whatever between the density of population and the quantity of rainfall, one early duty of a Government is to see that all parts are amply supplied with the chief necessary of life. Englishmen have a dread of centralisation, but in many ways they pay a long price for their dread. At present, it is not often that any town can even state before Parliament its views as to the effect upon it of what its next neighbour may be obtaining powers to do. Having suggested one semi-legal question, I may as well mention at once another. Up to the present time, there being no Hydraulic-office (as I hold that there should bc) in this country, all the larger water questions come before Parliament as private Bills, and, provided that they get through Committee, they, as a matter of course, become law-law for all time to come. No one can foresee what will be the total population of this country a century hence. No one can tell where the bulk of the people will reside, nor what will be the need for water in various parts of the