March 16, 1882} 
NATURE 
407 
Now the principal difference between the two proposed 
routes consists in the fact that Sir E. Watkins’ tunnel 
starts in the impermeable portion of the chalk with a 
view to following it all across, while Sir J. Hawkshaw’s 
tunnel starts in the lower part of the Upper Chalk, and 
descends subsequently into the Lower Chalk, probably 
into that portion of it which, as stated by Prof. Hébert, 
is less permeable than the Craie de Rouen itself. The 
possible difficulties that may arise from following the base 
of the chalk too closely have already been pointed out. 
It remains to be seen how far the fact of starting in the 
Upper Chalk is prejudicial. 
In spite of the vast quantities of water that have been 
obtained from the Chalk,! there are many instances of 
wells and deep bore-holes having failed to obtain a 
supply. A well at Dover Castle, 363 feet deep, or 14 feet 
below low-water mark, and with a tunnel 160 feet long at 
the bottom, can be pumped dry in three hours by a 
30 horse-power engine (Statement by the Committee of 
the Channel Tunnel Company). Deep bore-holes, such 
as those at Harwich, Hampstead, Calais, and Grenelle, 
though traversing the whole Chalk system, have been 
unsuccessful, and many other instances might be quoted 
to show how uncertain is the amount obtainable by this 
means. The plan adopted at Ramsgate, and afterwards 
at Brighton in consequence of the supply from wells 
being inadequate, throws much light on the circulation of 
water in chalk. Mr. Easton (Brit. Assoc. Rep. 1872) 
states that a well was sunk, and the direction of the 
fissures having been ascertained, a tunnel was driven at 
right angles to them, so as to intercept the greatest 
number in the shortest distance. Such a tunnel driven 
under Goldstone Bottom traversed 160 feet of solid chalk 
without finding water. It then encountered an enormous 
fissure yielding 1000 gallons per minute. This was fol- 
lowed at about the same interval by another of about 
equal capacity. At the Lewes Road the fissures were 
about 30 feet apart and yielded about 100 to 150 gallons 
per minute. At Ramsgate the supply was obtained by 
driving parallel to the shore at about low water-mark. 
The fissures were observed by Mr. Easton to run at about 
right angles to the coast line, so that it is clear that a 
tunnel might have been driven in this direction for a long 
distance without cutting a fissure. That a tunnel can be 
driven even in the most favourable situation for tapping 
water has been proved by Sir J. Hawkshaw, who, in the 
discussion which followed Prof. Prestwich’s paper (P7oc. 
Inst. C.E. xxvii.), stated that ““he was now completing at 
Brighton a tunnel of 54 miles in length, wholly through 
the Upper Chalk and below the level and within a short 
distance of the sea, There was a large amount of water 
from land-springs, The quantity of water pumped varied 
from 8,600 to 10,000 gallons per minute. This was a 
large quantity, but it did not prevent the tunnel from 
proceeding.’ The same length of tunnelling taken sea- 
wards at a greater depth might have carried the works 
clear of these difficulties, for there is reason to believe 
the fissures are most numerous and widest above or near 
the sea-level. 
These fissures, originally mere cracks due to unequal 
contraction or expansion in the mass of the chalk, owe 
their enlargement to the passage of water through them, 
acting partly mechanically by erosion, partly chemically 
by dissolving the carbonate of lime. Although they are 
met with at considerable depths, as for instance in the 
borehole at St. Margaret’s Bay, where a cavity of 3 feet 
depth, and filled with salt water, was found at 209 feet, 
yet they are most numerous where the circulation is most 
active, namely, about the water-level. It is at this level, 
as well as above the outcrop of an impermeable bed, that 
the largest inland springs occur, and it is at the sea-level 
* Inthe discussion on a paper by Mr. Lucas (Proc. Inst. C.E. xlvii.) Mr. 
Homersham stated that 11,000,000 to 12,000,000 gallons daily had been 
taken from the chalk in an area of 150 square miles about London for some 
years. 
that the largest quantity of water escapes from the cliffs 
on the coast. Beneath the waters of the Channel there 
may be but little movement in the rock-water, and what 
fissures or faults may exist, as well as the channels follow- 
ing the layers of flints are probably more or less choked 
from long disuse. While therefore it is not likely that 
the approaches to a tunnel can be made under the coast 
in the Upper Chalk without meeting with much water, it 
does not necessarily follow that the quantity will be so 
great as to be utterly unmanageable. That it is expected 
to be considerable may be inferred from a statement by 
Sir John Hawkshaw in the discussion before referred to, 
that the engines used in the Brighton tunnel “were, in 
the aggregate, of 150 horse-power, but provision had been 
made in estimating the possible cost of the Channel 
tunnel, for engines of about 2000 horse-power.” : 
Finally, it may be stated that the works, so far as they 
have gone, have confirmed the expectations formed as to 
the character of the rocks. The shaft at the west end of 
Abbot’s Cliff Tunnel has been taken to a depth of 160 
feet, and a drift-way carried in the Lower Chalk for 
1100 yards in the line of the tunnel proposed by Sir E. 
Watkin, without meeting water. On the French side 
two shafts have been sunk near Sangatte to a depth of 
280 feet, entering the Craie de Rouen at the sea-level, and 
a tunnel has been driven in a north-easterly direction at 
about 170 feet below the sea-level, with trial holes at 
intervals to the Gault, which is about 7 feet below. A 
little water issues from these, but the total amount that 
has to be pumped does not exceed 80 gallons a minute. 
Up to the present time no further trials have been made in 
the Upper Chalk at the spot selected for the works by 
Sir J. Hawkshaw. A. STRAHAN 
SIR CHARLES WYVILLE THOMSON 
HE news of the death of Sir Wyville Thomson, on 
the roth instant, from the effects of paralysis, will 
be received with general regret. Sir Wyville was only 
in the 53rd year of his age. On the return of the Cha/- 
lenger, we gave so full an account of Sir Wyville’s life 
and work (vol. xiv. p. 85) that we need not go over the 
same ground again. 
Charles Wyville Thomson was a descendant of an old 
Scottish family which had long resided at Bonsyde, Lin- 
lithgow. His father was a surgeon in the service of the 
East India Company. Born at the family residence on 
March 5, 1830, Wyville Thomson became, at the age of 
twenty-one, a lecturer on Botany in King’s College, 
Aberdeen. In 1853 he became Professor of Natu- 
ral History in Queen’s College, Cork; but he had only 
been there a year when he succeeded to the Chair of 
Mineralogy and Geology in Queen’s College, Belfast. 
In the expeditions of the Lightning and Porcupine in 
1868 and 1869 he took part, and the discoveries then 
made in regard to the fauna of the Atlantic Ocean he 
subsequently gave to the world in a work entitled ‘‘ The 
Depths of the Sea.” On the resignation of Prof. Allman, 
Prof. Thomson was elected Regius Professor of Natural 
History in the University of Edinburgh, where his 
abilities as a lecturer raised the class of zoology to 
a position of great importance, the numbers attend- 
ing it being probably unequalled. Of the famous 
expedition in the Challenger, Prof. Thomson was 
appointed the scientific chief. Leaving England in 
1872, the exploring party was absent for three and a 
half years, during which time 68,890 miles were traversed, 
and systematic observations made at 362 stations in the 
open sea, notes being also made on land and in shallow 
water, as opportunity offered. The natural history and 
other collections obtained were very extensive. These 
large collections were from time to time sent home to 
Edinburgh, where the head office of the expedition was 
subsequently established; and it was only appropriate 
