482 
NA TURE 
[ Sept. 16, 1886 
several returns had been received. The rate and mode of 
erosion of the chalk cliffs at the north-west part of the Isle of 
Thanet is described by Mr. R. B. Grantham ; in places as much 
as 20 feet in width of cliff has been lost in five years, but the 
average loss is not so much. 
Capt. T. Griffiths and Mr. H. W. Williams contribute a 
report on the north-west coast of Pembrokeshire, where the 
alterations are in places important, and in all are historically 
interesting. 
A report by Mr. K. McAlpine, on Pembrokeshire, illustrated 
by numerous photographs, was also laid before the meeting. 
The Twelfth Report of the Committee on the Circulation 
of Underground Waters, by C. E. De Rance.—During the 
thirteen years the investigation had been going on much valuable 
information had been obtained ; the complete dependence of the 
supply of underground water on the annual rainfall and the cha- 
racter and porosity of the strata on which the rain fell, had been 
completely established, varying from one inch to twelve inches of 
rainfall annually absorbed on each square mile ; one inch of rain 
giving 40,000 gallons per day for each square mile of surface 
exposed. The great value of underground supplies had been 
shown during severe droughts, the dry-weather flow of the 
streams and rivers being wholly dependent on underground sup- 
plies issuing as deep-seated springs. Large quantities of water 
could be obtained by deep wells in suitable situations, as was well 
shown by the Birmingham Corporation supply,—the Aston well 
yielding 3 million gallons a day, the Witton well 24 million 
gallons, King’s Vale a quarter of a million gallons, Perry well 2 
million gallons, Selby Oak well 1} million gallons, giving a total 
supply from wells of 9 million gallonsa day, the remaining sup- 
ply being from streams yielding 74 million gallons a day ; giving 
a total supply of 164 million gallons, of which only 12 are 
required at present. Large supplies of pure artesian well waters 
are obtained and used at Nottingham, Liverpool, and Birken- 
head. The supplies to other cities were investigated, and the 
recent successful borings at Stafford commented on. 
Report of the Committee, consisting of Mr. Fohn Cordeaux 
(Secretary), Prof. A. Newton, Mr. T. A. Harvie-Brown, Mr. 
William Eagle Clarke, Mr. R. M. Barrington, and Mr. A. G. 
More, re-appointed at Aberdeen for the Purpose of Obtaining 
(with the consent of the Master and Brethren of the Trinity 
House and the Commissioners of Northern and TLrish Lights) 
Observations on the Migration of Birds at Lighthouses and 
Light-vessels, and of reporting on the same.—The General Re- 
port of the Committee, of which this is an abstract, is comprised 
in a pamphlet of 173 pages,! and includes observations taken at 
lighthouses and light-vessels, as well as at several land stations, 
on the coasts of Great Britain and Ireland and the outlying 
islands. The best thanks of the Committee are due to their 
numerous observers for their assistance. Much good work has 
been rendered by those amongst them who have taken the 
trouble to forward a leg and wing of such specimens as have 
been killed against the lanterns, and which they have themselves 
not been able to identify. This has already led to the deter- 
mination of several rare birds, which otherwise would have 
escaped notice. It is evident that, unless the birds can be cor- 
rectly named, the value of this inquiry is materially diminished, 
and ornithologists may justly refuse to accept the accuracy of 
the statements. It is intended, in order to facilitate the sending 
of wings, to supply the light-keepers with large linen-lined en- 
velopes, ready stamped, and inclosing labels for dates and other 
particulars. The best thanks of the Committee are also ten- 
dered to Mr. H. Gatke for the increased interest he has given 
to their Report by forwarding a daily record of the migration of 
birds as observed at Heligoland between January 1 and Decem- 
ber 31, with the concurrent meteorological conditions under 
which the various phenomena occurred. Altogether 187 stations 
were supplied with printed schedules for registering the observa- 
tions, and returns have been sent in from 125. About 267 
separate schedules have been sent in to your reporters. The 
general results, as far as the special object of the inquiry, have 
been very satisfactory, and much information has also been ac- 
cumulated respecting the breeding habits of sea-fowl on the 
outlying islands and skerries on the Scotch and Irish coasts, and 
altogether a great mass of facts and valuable data obtained 
which cannot fail to be of value to future inquirers. A special 
* **Report on the Migration of Birds in the Springand Autumn of 1835.”” 
(McFarlane and Erskine, 19, St. James’s Square, Edinburgh.) 
point of interest in the Report is the large arrival, with a north- 
east wind, of pied flycatchers in the first week in May 1885, 
observed at Spurn Point, Flamborough Head, the Isle of May, 
and Pentland Skerries. | At Flamborough Head the flycatchers 
were accompanied by male redstarts in large numbers, both 
species swarming for two or three days. The immigration at 
this period was not exclusively confined to these two species. 
Mr. Agnew, writing from the Isle of May, at the entrance of 
the Firth of Forth, says, under date of May 3:—‘‘ An extra- 
ordinary rush of migrants to-day ; have never seen anything like 
it in spring. To attempt to give numbers is simply useless. I 
will just give you the names in succession : fieldfares, redwings, 
ring-ouzels, blackbirds, lapwings, dotterels, rock-pigeons, hawk, 
meadow pipits, redstarts, whinchats, tree-sparrows, yellow wag- 
tails, ortolan (obtained), robins, chiff-chaffs, wood-warbler, 
blackcap-warbler, marsh-tit, whitethroats, and pied flycatchers.” 
And on the 4th: ‘‘ Stil increasing in numbers, but wind shifted 
this morning to E. for S.E.” A noteworthy incident also of 
the vernal migration was the great rush of wheatears observed at 
the Bahama Bank vessel off the Isle of Man, and at Langness on 
the night of April 13, when many perished and were captured. 
On the same night, wheatears were killed at the Coningbeg and 
Rathlin Island Lighthouses on the Irish coast. On the 12th 
and 13th the rush was very heavy at stations on the west coast 
of Scotland. No corresponding movement was observed on the 
east coast of Great Britain on the same night; but at Hanois 
L.H., Guernsey, on May 10, at night at the north light, and on 
the Lincolnshire coast and Farn Islands on the roth and 11th. 
These entries are sufficient to show the immense area covered 
by the migration of this species at or about the same period. 
On the east coast of England the first wheatears were observed 
at the Farn Islands on February 22. The autumnal migration 
is first indicated at Heligoland on July 6, and was continued 
with slight intermissions up to the end of the year. A similar 
movement affected the whole of the east coast of Great Britain 
during the same period, but was apparently less constant and 
persistent than at Heligoland. It has been remarked in previous 
Reports that the migration of a species extends over many weeks, 
and in some cases is extended for months. Yet it is observable 
that, at least on the east coast of England, year by year, the 
bulk or main body of the birds come in two enormous and 
almost continuous rushes during the second and third weeks in 
October and the corresponding weeks in November. In the 
autumn of 1885 it is again observable that the chief general 
movements which usually characterise the southward autumnal 
passage were two in number, and affected the stations over the 
whole coast-line both east and west of Great Britain. The first 
of these commenced about October 11, and was continued to 
the 20th. The second from November 8 to 12. It is worthy 
of notice that these two chief movements of the autumn were 
ushered in by, and concurrent with, anti-cyclonic conditions, 
preceded by, and ceasing with, cyclonic depressions, affecting, 
more or less, the whole of the British Isles. From this it appears 
not unlikely that birds await the approach of favourable meteoro- 
logical conditions, of which, perhaps, their more acute senses give 
them timely warning, to migrate in mass. Whatever may be the 
cause which impels these enormous rushes, often continuous for 
days, it is one which operates over an immense area at one and 
the same time. The October rush reached its maximum on the 
16th, at which date almost all the stations report extraordinary 
numbers of various species on the wing. As one out of many, 
we quote from the journal of Mr. James Jack, principal of 
the Bell Rock Lighthouse :—‘‘ Birds began to arrive at 7.30 
p.m., striking lightly and flying off again ; numbers went 
on increasing till midnight, when it seemed that a vast flock 
had arrived, as they now swarmed in the rays of light, and, 
striking hard, fell dead on balcony or rebounded into the sea. 
At 3.a.m. another flock seemed to have arrived, as the numbers 
now increased in density ; at the same time all kinds crowded 
on to the lantern windows, trying to force their way to the 
light. The noise they made shrieking and battering the 
windows baflles description. The birds were now apparently in 
thousands; nothing ever seen here like it by us keepers. 
Wherever there was a light visible in the building they tried 
to force their way to it. ‘lhe bedroom windows being open as 
usual for air all night, they got in and put the lights out. All 
birds went offat 6a.m., going W.S.W. Redwings were most 
in number, starlings next, blackbirds, fieldfares, and larks.” 
The rush in November chiefly took place in the night; at the 
Bell Rock the movement ceased at midnight of the 12th, and at 
a Nl a OED Me A EL AN AE AN ese 
sis mgd ay “cms Per a AE AONE AE EN I AE NEA RE 
