April io, 19 13] 



NATURE 



'39 



migration — on April 17 and 18, 23, 27 and 28 — 

 each of increasing intensity. There was another 

 large influx on May 5. The immigrations of the 

 willow-warbler (probably two races'), which lasted 

 from March 1 1 to May 6, and of the wheatear (two 

 races), from March 19 to May 10, covered the 

 longest periods among the species recorded; while 

 those of the wood-warbler between April 16 and 

 May 13 occupied the shortest time. Notice is 

 drawn to the increasing and now extreme scarcity 

 of the landrail in the south-east of England. 



The records which are of most interest merely 

 in themselves are perhaps those to be found in the 

 section dealing with the autumn movements. The 

 autumn of 1910 was noteworthy for the large 

 influx of certain northern species, such as the u ax- 

 wing, northern bullfinch, mealy redpoll, and con- 

 tinental great tits. Jays were recorded as migrants 

 to the south-east of England, and with them 

 magpies (a flock of twenty), the latter being thus 

 for the first time recorded as migrants to our 

 shores. Great numbers of the little golden-crested 

 wren were on the move round all our coasts 

 between the end of August and mid-November. 



LONDON 1VELLS. 1 

 T T OYV complex and how serious is the problem 

 *- -*- of maintaining a supply of water suitable 

 to its needs few of the inhabitants of London 

 have any conception. We turn the tap for our 

 morning tub or to fill the kettle for tea and would 

 be surprised and annoyed if the water did not 

 readily flow. During the past few years, how- 

 ever, many large users of water have turned 

 their attention to the provision of private supplies, 

 and the number of wells has greatly increased. 

 The early wells of the city and surrounding area 

 were dug in the superficial gravels and Tertiary 

 formations alone, for in those days they yielded 

 a satisfactory supply without the need of descend- 

 ing further; gradually these shallow wells pro- 

 duced a smaller volume and a deteriorating quality 

 of water, and had to be deepened and sunk into 

 the Chalk. 



According to the researches of Mr. A. S. Foord, 

 there were no deep wells either in or near the 

 city till at least the middle of the eighteenth 

 century. It is probable that the difficulty of deal- 

 ing with the mobile Thanet Sands delayed the 

 introduction of deep wells until the art of over- 

 coming the trouble had been perfected. The yield 

 of many of the older wells was increased by put- 

 ting a boring at the bottom. Now, the practice 

 of sinking shafts is almost abandoned in favour 

 of boring alone. These borings are lined in the 

 upper portion and are carried as far as necessary 

 into the Chalk. This change has been brought 

 about by the fact that borings are cheaper than 

 dug wells, and that the latter would have to be 

 sunk at least 100 ft. before any water could 

 be reached. 



The height of the water level in London wells 



1 Memoir of the Geological Survey, Eneland and Wales. Records of 

 London Wells, bv G. Barrow and L. J. Wills. (1111. Stationery Office, 

 1913.) Price 4s. id. 



has been sinking for a long time, but in recent 

 years the fall has been increasingly rapid. This 

 is most clearly brought out in the memoir before 

 us by maps showing the contours of the under- 

 ground water-surface and by the data supplied 

 with many of the well records. The lowering of 

 tlie water-level, if continued at the present rate, 

 must seriously affect all wells in the London area. 

 not only as regards quantity, but also quite 

 possibly with respect to quality also. Mr. Barrow- 

 has great faith in a remedy for this evil, one 

 which has already proved effective in the hands 

 of Mr. W. B. Bryan in maintaining the level in 

 the waterworks district at Lea ' Bridge. He 

 recommends that spare water should be conserved 

 in reservoirs in suitable districts and poured as 

 required into dumb wells sunk into the Thanet 

 sand, whence it would permeate into the Chalk ; 

 in the introduction to the memoir he brings for- 

 ward a good deal of evidence in support of this 

 method. 



The influence of the Tertiary cover on the quality 

 of the water drawn from the Chalk is remarkable'. 

 Water taken from the Chalk beyond the Tertiary 

 outcrop carries a preponderance of lime salts'; 

 that from the Chalk beneath the Tertiary is much 

 poorer in lime, which the sodium salts have greatly 

 increased. This change is usually attributed to 

 the influence of the Thanet sand. Dr. Thresh 's 

 valuable experiments on the effects of this sand 

 are briefly discussed ; but this is a subject of great 

 complexity and requires further study. The work 

 on soils carried out by various agronomic surveys, 

 and that of Cushman and others on the influences 

 of colloids in clays, should have some bearing on 

 the problem. 



The well records in this volume are very 

 numerous, and many are published for the first 

 time. They should prove of the utmost value 

 gathered together in this form. Only by complete 

 and accurate records and their careful correlation 

 with geological conditions can an outlook be 

 obtained on the state of the underground water 

 as a whole. If the recording of all borings for 

 water in the United Kingdom were made com- 

 pulsory, much unnecessary waste would be 

 avoided. 



THE LISTER MEMORIAL FUND. 

 \\7E are informed that the contributions recently 

 * V made to the Lister Memorial Fund include 

 the following: Clothworkers' Company, ioo/. ; 

 Grocers' Company, 52/. 105. ; Ironmongers' Com- 

 pany, 257. ; Mercers' Company, 105L ; Merchant 

 Taylors' Company, 262/. 10s. ; Skinners' Com- 

 pany, 105/. ; Society of Apothecaries, 52/. 10s. ; 

 Corporation of the City of Glasgow, 52Z. 10s. ; 

 Royal College of Physicians, 21/. ; Royal College 

 of Surgeons, 52/. io.v. ; Royal Dublin Society, 

 50Z. ; Royal Horticultural Society, 52/. 105. ; the 

 Royal Society, 50?. ; Harveian Society, 10Z. 10s. ; 

 Pharmaceutical Society, 10/. 10.?. ; Physiological 

 Society, 10?. 10s. ; Royal Microscopical Society, 

 5Z. 55. ; Royal Sanitary Institute, ^l. «. ; the 



NO. 2267, VOL. 91] 



