THE FORMATION OF SALINE MINERAL WATERS. 829 



port such a temperature in the presence of water without being de- 

 composed. 



As the process of cooling continued, the atmosphere kept inces- 

 santly yielding by condensation the water which it held, and this 

 water kept perpetually dissolving the soluble salts which it found 

 already present, and also those that were continuously produced by 

 the action of the acids it bore with it. As we have already seen, 

 these salts were sulphates and chlorides. On the other hand, the 

 metals competent to combine with the sulphur and the chlorine were 

 necessarily those existing in the rocks that formed the first crust of 

 consolidation, and these metals were, as we shall be able to show, 

 lithium, potassium, sodium, magnesium, and calcium. Now, it is these 

 five metals which, united with chlorine and sulphur, constitute nearly 

 the total amount of the salts dissolved in the waters of the seas. 

 Such, to my mind, is the origin of the salts which mineralize the 

 seas ; and it is an origin wholly exterior.* Thus, from the most 

 ancient aqueous period of our planet, from the time when its external 

 temperature was not notably below the boiling-point of water, and 

 from a time, consequently, before any trace of life was possible, the 

 seas have had essentially the same composition they have to-day. 

 Zoologists have for a long time regarded this fact as necessary, be- 

 cause the animals whose remains have been found in the most ancient 

 sedimentary beds did not differ as to their general plan from their 

 congeners in modern seas, and could not, consequently, have lived in 

 waters that differed sensibly in composition from the water of exist- 

 ing seas. 



If the whole mass of chlorides and sulphates was originally dis- 

 solved in the sea- waters, then the only way we have of explaining the 

 origin of the saline formations which exist in the sedimentary beds 

 is to assume that they have been left by the spontaneous evaporation 

 of parts of the ancient seas accidentally isolated from the oceans. 

 I came to this conclusion long ago, not by a more or less intuitive 

 suggestion, but drawn to it by the logic of facts and the ideas I am 

 about to present. This conclusion once formulated, I have taken the 

 consequences, as numerous as important, which it involves, and have 

 submitted them to an experimental verification. 



In approaching the experimental side of my investigations, I had 

 first to study in its details what takes place when the waters of exist- 

 ing seas are left to spontaneous evaporation. 



First, a very weak precipitation occurs of carbonate of lime with a 

 trace of strontium, and of hydrated sesquioxide of iron, mingled with 



* An objection may be raised to this idea, from the fact that a large number of 

 chlorides and sulphurous products are developed in modern volcanic phenomena which 

 we all agree came up from a very profound zone. I refer to it to state that I am pre- 

 pared to meet it and have elements sufficient to show that the two orders of facts are 

 perfectly reconcilable. 



