164 Abstracts of Foreign Memoirs. 
The figure now given of the species may be therefore considered as 
representative. 
While staying with Mr. Wood, I had an agreeable excursion to 
the lead-mines of Old Gang, in the higher and wilder parts of Swale- 
Dale, being guided over this really wonderful district by its pro- 
prietor, Sir George W. Denys, Bart. The excessively steep and rugged 
combs which characterize this dale afford some exceedingly fine 
geological sections in the Mountain-limestone series, but are so 
trying to the physique, that I must be pardoned if I brought away 
few notes beyond a general sense of the remarkable characters of the 
lead-bearing rocks. Galena is the ore worked, in lodes of very 
variable richness. The distance of the mines from any railway, and 
the necessary expenses of cartage, are against them; else I scarcely 
know a lead-bearing district in England which might compete with 
this, were the veins fully explored, and were there such facilities 
of carriage for the ore (or smelted metal) as a railway passing the 
district would give. 
Much has been said about the occurrence of copper in the Moun- 
tain-limestones of the North Riding. I fear that any copper-ores 
worked within the acknowledged geological limits of these rocks, will 
bring but little of the nobler metal to the pockets of their owners ; 
but as an amateur mineralogist, I was greatly interested in a splendid 
specimen of chrysocolla, of very pure quality, obtained shortly before 
my visit by Sir G. W. Denys from his mines at Roughten Gill, Calbeck. 
It more nearly resembled in colour and lustre the chrysocolla of 
Siberia than that of Cornwall. 
ABSTRACTS OF FOREIGN MEMOTRS.- 
en 
MINERAL WATERS CONSIDERED IN THEIR RELATIONS WITH 
CHEMISTRY AND GEOLOGY. 
Lus Eaux Minérarss, etc. Par H. Lucoa.—( Continued from page 116.) 
The temperature of mineral waters varies extremely. Some are 
cold,—probably (according to M. Lecoq) cooled in rising; most of 
them are warm. Some are boiling, bursting out at the bottom of 
the sea, and bubbling up at the surface. Ata small depth below the 
earth’s surface the temperature of some thermal springs is far above 
the boiling-point of water. -The Auvergne springs do not rise 
above 82° C. (180° F.), but they are believed by M. Lecoq to have 
been higher when the volcanos were active. In the Pyrenees the 
hottest springs do not exceed 78° C. (1724° F.). M. Daubrée has 
estimated the quantity of heat emitted by 45 French springs, whose 
volume is approximately known, as sufficient to melt a film of ice, 
at the temperature of 0° C. (32° F.), having a thickness of 0™-00000324 
(0001275 inch.). This is certainly a very small quantity, but 
M. Lecoq speculates on the much greater influence of hot springs 
during earlier geological periods. 
The contents of mineral waters vary also both in nature and 
