596 
PROFESSOR FORBES ON THE TEMPERATURES 
in the Vall6e d’Aran is seated, and which is probably intimately connected with that 
of Luchon, which is not many miles distant. 
B. C. Specialties and Temperature. — The springs are trifling and unstable. They 
are sulphureous, and contain much baregine. Of the two principal ones, the one (A.) 
rises in the bottom of a deep narrow cistern, and disengages much gas (probably 
azote) ; the other flows into the same cistern by the side. As nearly as I could de- 
termine them on the 16th of August 1835, the temperatures were 
Crichton. Reduced. 
(A.) 88-0 86*4 
(B.) 84-3 82*9 
Bagneres de Luchon limits, for the most part to the eastward, the excursions of 
travellers, whether in search of health or amusement. We should form, however, 
but an imperfect conception of the Pyrenean range by confining ourselves to the fre- 
quented little district bounded by Cauteretz and Luchon. Least of all should we 
appreciate the marvellous abundance of its mineralized springs by such a survey. To 
see these in their true character we must visit the departments of the Arriege and of 
the Pyrenees Orientales, districts little known even to Frenchmen, nay, almost over- 
looked even by some French writers on mineral waters, although perhaps they are 
the most abundant, and nearly the most powerful in their action and elevated in their 
temperature, of any in Europe. Whilst in the over-crowded establishment of Bareges 
invalids are compelled to economize the water by bathing at all hours of the night, 
waters containing the very same ingredients, far more abundant, and of far more 
varied temperatures, are running to waste in the Eastern Pyrenees. 
X. Aulus. 
A. Geological Position, 8$c. — At not a very great distance, in a right line to the 
eastward of the last-mentioned place, Lez, the traveller finds the village of Aulus. He 
will, however, probably reach it by a circuitous route, since even if he travel on foot 
or horseback his most natural course* from Bagneres de Luchon is by St. Beat, Cas- 
tillon, St. Girons, and the Valley of Sallat, up its tributary valley, that of Erce, near 
the head of which, amidst grand scenery and in profound seclusion, lies the humble 
watering-place of Aulus. I mention the baths of Aulus, like those of Lez, merely on 
account of their geological position, which is exactly at the junction of granite with 
stratified rocks. 1 was given to understand that the springs are ferruginous, and of 
low temperature, which prevented me from examining them, though I am not now 
* This route is also the most interesting, because it brings us in contact with several examples of that very 
singular formation, the ophite of Palassou. It is particularly exposed near the Col de Mende, at St. Lary in 
the Vallongue, and at Lacour in the Valley of Sallat ; gypsunfaccompanies it in the latter site, and epidote 
most abundantly. I feel no doubt as to the general common character of this and our trap rocks. It is ge- 
nerally admitted that the hot springs of Dax near Bayonne (a point which I much regret not to have visited) 
owe their high temperature and mineralization to this intrusive rock. 
