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PROFESSOR FORBES ON THE TEMPERATURES 
XV. Thuez. 
A. Geological Position . — The springs of Thuez are very remarkable, on account of 
their great number, high temperature, varied composition, and absolutely neglected 
condition. They rise near the torrent called La Tet, or Teta, which derives its 
name from the great valley which it traverses, almost entirely excavated in granite, 
and extending from Mont Louis to near Perpignan, in a direction from west to 
east. The occurrence of mineral waters in it is attended with some interesting 
peculiarities. There is a large patch of limestone insulated by granite, and upon 
which the town of Villefranche is built, between Olette and Prades ; and what is most 
curious is, that we find springs encircling this insulated portion of stratified rock, 
though they all take their rise in the granite. Such are the springs of Molitg, Vernet, 
and Thuez. It is only with the latter that we have now to do. The commune of 
Thuez is situated a little above the junction of the granite and stratified rock ; but 
there are two physical peculiarities that deserve notice: 1. That the immediate focus 
of thermal action is close to the Graus ch Olette, a winding part of the road, rendered 
necessary by the narrowness of the ravine which the torrent penetrates. There can 
hardly be a doubt that this is a line of fissure ; and it is precisely at this fissure that 
the springs rise most abundantly. It may also be observed, that the hot springs here 
take their rise remarkably from the precipitous banks of tributary torrents whose 
beds have perhaps formed subordinate fissures. 2. Almost at the same point is the 
copper mine of Canavielles in granite. Hence, as at St. Sauveur, we have the co- 
ordinate (and I think connected) phenomena of intrusive rocks, dislocations or 
fissures, metalliferous impregnation, and hot springs. 
13. Specialties of the Springs . — Nothing can give a fitter idea of the necessity of 
the precautions we have adopted for identifying the springs described in this paper, 
and also of the number and importance of those of Roussillon, than the fact, that 
with the minute and faithful work of Anglada before me, I have had great difficulty 
in ascertaining whether or not the springs which I observed occur amongst those 
mentioned by him at Thuez. Indeed, considering their wild and almost inaccessible 
position, the little interest taken by the people in them, and the impossibility of 
making inyself understood where nothing is spoken but the Catalonian dialect, I had 
rather cause of congratulation that I should have discovered any of them. Even the 
“ zele hydrologique” of Anglada was almost exhausted on the banks of the Tet, 
where, he observes, “ il m’est surtout arrive d’executer des analyses, suspendu, pour 
ainsi dire, sur des abimes.” A complete examination of springs so abundant and so 
varied, (partaking of the medicinal characters of the waters of Bareges, Plombieres, 
and Bagnhres,) which are, besides, the hottest in the Pyrenees, could not fail to be 
of the highest interest in a general as well as a scientific point of view. I was 
instructed to cross the river Tet (from the left to the right bank) a little below Thuez. 
I found myself at the foot of a steep rocky bank covered with tangled brushwood. I 
