Environs ofLoHs le Saunter. 139 



town not to be fit for dressing vegetables or for the purposes 

 of washing, owing to its containing sulphate of lime. 



It is then very probable that the knoll of Pimont contains 

 gypsum. On the other hand, the invariable abundance and 

 elevation in the valley of the saline spring, shew that the 

 waters come from an elevated place offering a large surface 

 to the rains. 



Now, the knoll of Pimont, which of all the surrounding 

 hills most indicates the presence of gypsum, is still the only 

 one, within a radius of more than three kilometres [12,000 

 feet] that unites these two conditions ; it may then be 

 presumed that it contains also the saline rock traversed by 

 the rain water before it arrives at the spring. 



It will not be misplaced to mention here a phenomenon 

 rather frequent in the Jura, which is essentially owing to 

 the formation I am describing ; I mean of the funnels which 

 suddenly form, by the sinking of the surface of the ground. 



The machines for the extraction of the salt water are 

 placed at the bottom of a vast funnel 16 metres [about 52 ft.} 

 deep, which has originated in a sinking of the ground, at 

 an unknown but no very distant period. 



In 1792, a considerable sinking took place in the Rue 

 des Dames ; the inhabitants of the town were seized with 

 the greatest fear, when they saw a house gradually sink and 

 disappear in a gulf which was immediately filled with water. 



Witnesses worthy of credit state, that the waters of the 

 saline spring suddenly became low, and were greatly dis- 

 turbed during this event. 



Lastly, there recently occurred between the two former, 

 a third, but much less considerable sinking ; although I waS 

 not at that time present, I nevertheless learned with cer- 

 tainty, that the spring was again disturbed by this cause. 



The explanation of the fact is very simple ; it can be 

 conceived, without having recourse to any hypothesis, that 

 the systems of enormous beds, when upset into the positions 

 in which we now see them, could not coincide so exactly 

 with the inferior rocks, as not to leave some empty spaces 

 between them. 



