252 Abstracts of Memoirs. 
F. to 118° F. Some yield very small quantities of water, and their 
total yield is about 48 gallons per minute. ‘The water issues clear, 
and slightly acidulous, and becomes cloudy on exposure to the air. 
Carbonic acid gas is emitted with the water, the quantity varying 
with the weather and in the different springs. One spring much 
colder than the rest yields a much larger quantity of gas than the 
others. Nitrogen and a little oxygen are also given off. The com- 
position of the waters is very complex, including bicarbonate of 
soda, potash, lime, lithia, magnesia, manganese, protoxide of iron, 
rubidium, and cxsium ;* chloride, iodide, and fluoride of sodium; 
sulphate, arseniate, and borate of soda; silica, alumina, and a trace 
of bituminous organic matter. 
M. Lecoq, with good reason, attaches much importance to the 
mineral deposits in the neighbourhood of springs. In those of Mont 
Dore he finds traces of iodine ; and Berthier has alluded to phos- 
phorus and fluorine. A considerable mass of resinous quartz was 
destroyed in building the thermal establishment. It contained sili- 
citied wood. It is thought that the quantity of silica in the water 
diminishes. 
A tufaceous deposit on the banks of the Dordogne, about 14 mile 
below Mont Dore, marks the springs of the Compitssade. 'They are 
three in number, issuing from trachyte, and flowing over travertin. 
Two are cold, and one is warm, the latter depositing silica. About 
23 miles beyond, out of fissures in granite and trachytic tufa, rise 
the springs of Za Bourboule. ‘They are seven in number, yielding 
about six gallons per minute, the temperature high but variable, 
sometimes nearly 180° F. They yield chiefly common salt and 
bicarbonate of soda. They also show traces of the chlorides of 
lithium and the new metals, phosphate and arseniate of soda, iodide 
and bromide of sodium. A slight odour of sulphuretted hydrogen is 
noticed at the springs, and they have a distinctly acid and salt taste. 
In the valley of Chaudefour are a number of small mineral springs, 
some warm and some cold. They are for the most part chalybeate. 
They yield, on the whole, about 60 gallons per minute. The new 
metals have not been detected in them; but they contain iodine, 
bromine, arsenic, phosphorus, and a calculable percentage of sulphate 
of strontia. All yield carbonic acid gas. A large deposit of car- 
bonate of lime is obtained from the waters of St. Nectaire, and 
advantage is taken of this in the manufacture of natural cameos 
resembling those of Tuscany. 
In traversing the granite, these mineral waters change and de- 
compose the felspar, and cause the rock to disintegrate, while occa- 
sionally crystals of arragonite are deposited in the crevices and 
fissures of the rock. 
The second division of the mineral springs of the district in- 
cludes a number of outlying groups. Of those on the banks of 
the Allier, one (Saut du Loup) is intermittent; others (Woneéte, 
Coudes) rise through large masses of travertin ; another (Tam- 
bour, the Drum) issues with a rumbling noise ; others (Sé Mar- 
* It is from the mother-water derived from evaporating 200 litres (17 gallons) 
of water, that these metals and lithia have been determined, 
