220 Salt Springs of Moutiers. 



phuretted hydrogen ; it lias an acidulous and slightly saline taste. 

 These springs rise at the end of long passages, that have been exca- 

 vated in the rock. I broke off a piece of tl>e rock in contact with 

 the water ; it is a black imperfectly crystalline limestone, coated with 

 a thick ocherous incrustation. From the position of this rock, and 

 its connection with those on the other side the gorge, I have no doubt 

 that the spring rises from the lowest limestone in this part of the 

 Alps, where it comes in contact with dark schist, or talcous slate, as 

 I have observed to be the case in other parts of Savoy and the Haut 

 Vallais ; but the actual junction of the two rocks is not seen here. 

 The temperature of the strongest spring is 99° Farenheit ; it con- 

 tains 1'83 per cent, of saline matter. The second spring has the 

 temperature of 95°, and contains 1*75 of sahne matter. Other sour-, 

 ces have been discovered that contain only 1'50 of salt. I was told 

 that there is a deep and nearly inaccessible chasm in the rock be- 

 hind the springs, which is supposed to have some connection with 

 them. Beside common salt, the water contains in small proportions, 

 sulphate of lime, sulphate of soda, and sulphate and muriate of mag- 

 nesia, together with oxide of iron. Much of the gypsum in this part 

 the Tarentaise being intermixed with rock salt, we may well con- 

 ceive whence the water derives its saline impregnation ; but I am in- 

 clined to believe that the high temperature of these springs, as well 

 as of all the thermal waters in Savoy, is occasioned by an intermix- 

 ture of boiling water, which rises from immense depths, being heated 

 and forced up by subterranean fire, like the hot springs in countries 

 undoubtedly volcanic. During the great earthquake that destroyed 

 Lisbon in 1756, the salines at Moutiers ceased to flow for forty-eight 

 hours, and when they flowed again, their quantity was increased, but 

 the sahne impregnation was weaker. A similar effect was produced 

 at the same time at the hot springs of Toplitz, in Bohemia. 



It may seem extraordinary that the waters at Moutiers, which have 

 only half the strength of sea-water, should repay the expence of 

 evaporation ', but the process by which it is effected is both simple 

 and ingenious, and might be introduced with great advantage on ma- 

 ny parts of our own coast, should the salt duty be entirely removed. 

 The salt works at Bex, in the Pay de Vaud, are nearly similar to 

 those at Moutiers, but not on so extensive a scale ; and a very use- 

 ful part of the process at Moutiers is not adopted at Bex. Having 

 never seen an intelligible account of the process of evaporation by 

 faggots, I shall endeavor to give such a description as will enable any 



