382 



APPENDIX. 



Lisbon, and threw out hot water ; at the same period the warm saline 

 springs at Moutiers ceased to flow for forty-eight hours. When the 

 water returned, the quantity was said to be increased, and the saline 

 impregnation was weaker. Former and more formidable agitations of 

 the earth are recorded in the Haut Yalais, particularly in the district 

 where the principal hot springs are situated. The last earthquake of 

 consequence in the Valais took place in January, 1803. 



I am informed that several of the retired valleys on the Italian side 

 of the Alps, at the foot of the central chain, are subject to earthquakes, 

 during which the ground has opened or sunk down in various parts, 

 though these effects have been too local, to excite attention at a dis- 

 tance. From these facts, it seems as reasonable to infer that the ther- 

 mal waters of the Alps owe their high temperature to subterranean 

 fire, as that the hot springs in countries that have formerly been vol- 

 canic, derive their warmth from an internal, unextinguished, but qui- 

 escent, source of heat. No person who has attentively examined the 

 lofty granitic plain to the west of Clermont Ferrand in France, and 

 observed the granite in various parts pierced through by ancient vol- 

 canoes that have poured currents of lava over its surface, or seen oth- 

 er parts, where the granite itself has been changed by its contiguity 

 to subterranean fire, or upheaved and intermixed with volcanic rocks; 

 no one, I say, who has observed this, can doubt that the hot springs 

 of Mont d'Or and Vichy, derive their high temperature from a source 

 of heat situated beneath the granite mountains, though ages have pass- 

 ed away since the volcanoes of that country have been in an active 

 state, and the only proof of the present existence of subterranean fire 

 in Auvergne, is to be found in the hot springs themselves. Nor can 

 any adequate reason be assigned, for attributing the high temperature 

 of the thermal waters in the Alps, to any other cause than to a source 

 of subterranean fire under these mountains, — a cause which is suffi- 

 cient also to have produced their original elevation. It is, however, 

 proper to state, that in some of the mountains of the Alps, the tempe- 

 rature may be slightly increased by a cause hitherto unnoticed. In 

 the upper part of the secondary formations covering the granite, there 

 are beds of gypsum, and this gypsum is anhydrous ; but when exposed 

 to air and moisture, it combines with water, and passes to the state oi 

 common gypsum : during this combination we may suppose heat to 

 be evolved ; but the process must be extremely slow, and the heal 

 evolved, must be totally inadequate to raise the temperature of pow- 

 erful streams to 126°. Saussure found the temperature of the watei 

 in the lower part of the salt mines of Bex, which are situated in the 

 vicinity of gypsum, to be four degrees of Reaumur higher than the 

 mean temperature of the earth. It is not improbable, though Saus- 

 sure was not aware of the circumstance, that this small increase oi« 

 temperature in the mines of Bex, might be partly owing to the combi- 

 nation of water with gypsum : however, an increase of temperature,^ 

 it is well known, is observed in deep mines, far removed from the gyp- 

 sum formation. 



In reply to what I have advanced respecting the thermal waters ite 

 the Fenniae Alps, it may be said, that few thermal springs have beeia 

 yet discovered in the northern range of the Alps which form the Ber-^ 



