March 30, 1876] 



NATURE 



425 



keepers whose carpets are in danger from the attacks of 

 the Clothes Moth. " Take a wet sheet or other cloth, lay 

 it upon the carpet, and then run a hot flat-iron over it, so 

 as to convert the water into steam, which permeates the 

 carpet beneath and destroys the life of the inchoate moth." 



LETTERS TO THE EDITOR 



[ The Editor does not hold himself responsible for opinions expressed 

 by his cotrespondents, Neithtr can he undertake to return, 

 or to correspond with the -writers of, rejected manuscripts. 

 No notice is taken of anonymous communications. ^ 



Water-supply of the Metropolis 



I HAVE no intention of entering into a controvei-sy in your 

 columns with my friend Dr. Frankland, but his letter in your 

 impression of March i6 seems to require some reply. 



When I made the remarks which are called in question by Dr. 

 Frankland, I was careful to say that I might not unfairly be 

 accused of having done so from interested motives, an admission 

 of which no one who reads Dr. Frankland's letter can say that 

 he has not taken the full advantage. I am not ashamed of my 

 occupation, and am quite ready to admit another historical 

 parallel afforded by Jack Cade, and confess that I, or those who 

 have gone before me, "against the king, his crown, and dignity, 

 have built a paper-mill." But, whether paper-manufacturers 

 ' ' in the exercise of what they call their rights " are polluters of 

 streams or no, is a question into which I never entered, and is 

 entirely beside the points which I raised. 



These are in the main avoided by Dr. Frankland. The two 

 Commissioners, a portion of whose report I criticised, and of 

 whom it is as well to observe Dr. Frankland is one, recommend 

 that the Thames and the Lea should be entirely abandoned as 

 sources of supply for domestic use in London, and particularly 

 refer to the Chalk in the neighbourhood of London, and not to 

 the distant springs of the upper Thames as the future source of 

 supply. In his letter to jou Dr. Frankland states that " The 

 Commissioners advise that the drinking water cf London should 

 continue to be derived from its present sources, but that it should 

 be led away to its destination before it is mixed with tlie sewage 

 of Oxford, Reac'ing, Windsor, and other towns, and before it is 

 fouled by the filthy discharges of paper-mills, and by other dis- 

 gusting refuse." I presume that these two statements can be 

 reconciled, but looking at the proposal that the water should be 

 procured " within a moderate distance of London " the calcula- 

 tions as to the area of 849 square miles of Chalk and Upper Green- 

 sand within thirty miles of London, and looking at the enormous 

 expense of conveying water more than thirty miles, I took that 

 radius as representing the area cut of which some district was to 

 be placed under unnatural conditions with regard to its springs 

 and streams, in order to supply our vast metropolis, which I am 

 told it is contemptuous to term " overgrown." I never spoke of 

 the fertile meadows of the Thames valley, about which Dr. Frank- 

 land makes merry, and I never intentionally alluded in the 

 slightest degree to the main valley of the Thames, except to say 

 that both below and above London there might be spots in it 

 from v/hich a limited supply of water might be pumped without 

 much injury to the neighbouring property. My comments were 

 intended to be confined to districts in which the proposal of the 

 Commissioners could be carried out of sinking wells below the 

 present spring-heads, and so constantly drawing upon them that 

 there should be alwa)s a void below the level at which the 

 drainage naturally escapes. If this dees not mean the drying up 

 of the streams by cutting away their natural sources of supply I 

 shall be glad to know what it does mean. 



If Dr. Frankland were as well acquainted as I am with the 

 gravelly soil of some of the low meadows in Chalk districts, he 

 would cease to be surprised at the possibility of their being con- 

 vtrted into " arid wastes " by the abstraction of the water with 

 which they are now charged up to within ^a very few feet of their 

 surface. In the valley in which I live I have known the peaty 

 soil above such gravel, even without the artificial abstraction of 

 the moisture below, become during a dry summer sufficiently 

 arid accidentally to catch fire and continue burning for days. 



But then I am told that the wealthy City of London would be 

 able and wiUing to pay for any damage it might inflict in pro- 

 curing its water supply. I can only say that the word "com- 

 pensation " does not occur in the Index to the Report of the 

 Rivers Commissioners, and I have sought in vain for any allusion 



to it in the text Perhaps Dr. Frankland is not aware that at 

 the present time the state of the law is such that even when 

 compensation has been provided for by Act of Parliament, it has 

 been held to be inapplicable in the case of wells being dried, on 

 the ground that an action will not lie in respect of the loss of 

 underground water, and therefore that no statutable damage has 

 been inflicted. 



As to the prescription for increasing the supply of spring 

 water in a Chalk district by lowering the level of the subter- 

 ranean reservoir, I may observe that in most of such districts 

 floods are almost unknown, the soil being sufficiently absorbent 

 to imbibe all the rain that falls, except when by chance the sur- 

 face is frozen. The lowering of the water which, except in the 

 valleys, is now usually from 100 to 200 feet below the surface, 

 would make no difference in the receptive power of the soil on 

 the hills, and could not be effected in the valleys without laying 

 the streams, which now flow through them, dry. 



As to London encountering the expense of a separate water 

 supply for dietetic purposes, I can only say that if it can be 

 effected for 2,000,000/., as suggested by Dr. Frankland, it will 

 in my opinion be far cheaper than the plan the Commissioners 

 advocate. It is as a rule more economical to make use of what 

 we have, than to discard all existing apphances and commence 

 on a new system. Perhaps the Water Companies may have a 

 word to say on this point. 



The concluding paragraph of Dr. Frankland's letter seems to 

 have been written under some misapprehension. I distinctly 

 stated that "if we refer to the headings of Organic Carbon and 

 Organic Nitrogen there can be little doubt of the superiority of 

 the Kent Company's water.'' I may, however, be under some 

 misconception as to the statistics under the awful heading 

 " Previous Sewage or Animal Contamination," in which, pos- 

 sibly, I do not stand alone. What I ventured to suggest was 

 that the Commissioners on the W^ater Supply of the Metropolis, 

 within whose proper sphere this question lay, were not altogether 

 wrong in reporting, that with perfect filtration and efficient mea- 

 sures taken for excluding from the rivers the sewage and other 

 polluting matter, the Thames and Lea would afford water which 

 would be perfectly wholesome, and of suitable quaUty for the 

 supply of the metropolis. 



If this proved impossible, then I ventured to point out that 

 there was already in London a sufficient supply of water of the 

 kind recommended by the other body of Rivers Commissioners. 



I must not, however, waste your space and your reader's time, 

 but will in a few words mention my principal reason for taking 

 up this subject, which, however, apart from any such reason, I 

 considered would be of interest to geologists. 



It was this, that in an otherwise admirable and exhaustive 

 public report, measures were advocated involving in all proba- 

 bility great inconvenience and loss to large tracts of country, 

 without, so far as I could see, one single reference to such loss 

 and inconvenience. W^ith the advocates of a private scheme 

 such a disregard of injury to others would be reprehensible, 

 though possibly not uncommon, but some greater consideration 

 of the interests involved might fairly be expected from a public 

 document. John Evans 



Nash Mills, Hemel Hempsted, March 18 



Evidences of Ancient Glaciers in Central France 



M \N Y lovers of natural history who have not the opportunity 

 of seeing foreign scientific periodicals, may learn the advantage 

 of taking such a paper as Nature in the correspondence which 

 was published between Dr. Hooker of Kew and the late Mr. 

 Poulett Scrope, on the evidences of ancient glaciers iu Central 

 France. 



The objections raised by Mr. Poulett Scrope, and the pleasure 

 of examining such evidences as are adduced by Dr. Hooker, 

 have induced me to accept the invitation of friends, who also 

 enjoy such researches, to again visit Auvergne for the purpose of 

 examining the Mont Dore valley for glacial traces, and I would 

 gladly avail myself of any observations made by other geologists 

 in that region, if they would do me the favour of sending me the 

 notes of any locaUties to the address below. 



In the meantime M. A. von Lasaulx, of Breslau University, 

 claims the priority over Dr. Hooker in describing glacial traces 

 in the ^«j/««^ periodical, in 1872, as occurring at the entrance 

 of the '* Gorge d'Enfer." I have also before me, as I write, a 

 travelling note-book of Sir Wm. Guise, President of the Cots- 

 wold Naturalist Field Clnb (date, June, 1870), in which he refers 



