4 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 56 



Now I conceive that as all these lakes do receive rivers and have no exit or 

 discharge, so it will be necessary that their waters rise and cover the land, 

 until such time as their surfaces are sufficiently extended, so as to exhale in 

 vapor that water that is poured in by the rivers; and consequently that lakes 

 must be bigger or lesser, according to the quantity of the fresh they receive. 

 But the vapors thus exhaled are perfectly fresh; so that the saline particles 

 that are brought in by the rivers remain behind, while the fresh evaporates; 

 and hence it is evident that the salt in the lakes will be continually aug- 

 mented, and the water grow Salter and salter 



Now if this be the true reason of the saltness of these lakes, it is not improb- 

 able but that the ocean itself is become salt from the same cause, and we are 

 thereby furnished with an argument for estimating the duration of all things, 

 from an observation of the increment of saltness in their waters. For if it be 

 observed what quantity of salt is at present contained in a certain weight of 

 the water of the Caspian Sea, for example, taken at a certain place, in the 

 driest weather; and after some centuries of years the same weight of water, 

 taken in the same place and under the same circumstances, be found to con- 

 tain a sensibly greater quantity of salt than at the time of the first experiment, 

 we may by the rule of proportion, take an estimate of the whole time wherein 

 the water would acquire the degree of saltness we at present find in it. 



And this argument would be the more conclusive, if by a like experiment a 

 similar increase in the saltness of the ocean should be observed: for that, after 

 the same manner as aforesaid, receives innumerable rivers, all which deposit 

 their saline particles therein; and are again supplied, as I have elsewhere 

 shewn, by the vapors of the ocean, which rise therefrom in atoms of pure water, 

 without the least admixture of salt. But the rivers in their long passage over 

 the earth do imbibe some of the saline particles thereof, though in so small a 

 quantity as not to be perceived, unless in these their depositories after a long 

 tract of time. And if upon repeating the experiment, after another equal num- 

 ber of ages, it shall be found that the saltness is further increased with the same 

 increment as before, then what is now proposed as hypothetical would appear 

 little less than demonstrative. But since this argument can be of no use to our- 

 selves it requiring very great intervals of time to come to our conclusion, it 

 were to be wished that the ancient Greek and Latin authors had delivered down 

 to us the degree of the saltness of the sea, as it was about 2000 years ago; for 

 then it can not be doubted but that the difference between what is now found 

 and what then was, would become very sensible. I recommend it therefore to 

 the Society, as opportunity shall offer, to procure the experiments to be made of 

 the present degree of saltness of the ocean, and of as many of these lakes as 

 can be come at, that they may stand upon record for the benefit of future ages. 



If it be objected that the water of the ocean, and perhaps of some of these 

 lakes, might at the first beginning of things, in some measure contain salt, so 

 as to disturb the proportionality of the increase of saltness in them, I will not 

 dispute it: but shall observe that such a supposition would by so much con- 

 tract the age of the world, v/ithin the date to be derived from the foregoing 

 argument, which is chiefiy intended to refute the ancient notion, some have of 

 late entertained, of the eternity of all things; though perhaps by it the world 

 may be found much older than many have hitherto imagined. 



Ever since the publication of Mr. Joly's papers Mr. F. W. Clarke and I 

 have been deeply interested in his metliod and in chemical denndation. A 



