834 THE POPULAR SCIENCE MONTHLY. 



tant period sink below the level of the bottom of the channel that con- 

 nects the Karabogaz with it. 



The character of the Dead Sea is still in question. M. Lartet, of 

 Toulouse, who was connected with the expedition of the Due de 

 Luynes in 1866, fully recognizes the close analogy of its waters with 

 the mother- waters that are left from the evaporation of the waters of 

 normal seas ; but he believes that its waters owe their quality to ther- 

 mal springs, and that the sea never could have been in communication 

 with the Mediterranean or the Red Sea. He supports his view by the 

 assumed absence of certain substances common to sea-waters from its 

 waters ; but, as I have found these substances by analysis in Dead Sea 

 waters, I consider the argument resting upon that ground invalid. M. 

 Lortet, of Lyons, has recently made a discovery that indicates that 

 this lake once formed part of a normal sea. He has found near the 

 Lake of Tiberias a plateau covered with gravel and rounded pebbles, 

 situated at the exact level of the Mediterranean Sea. If the body of 

 water that washed these gravels and pebbles once occupied the valley 

 of the Jordan and the Dead Sea, then there once existed here a gulf 

 like that of Karabogaz. Separated from the oceans by some accident, 

 it has dried up ; its less soluble salts have been gradually deposited in 

 the shallower parts of the basin and constitute the saline masses which 

 are now found in the region products of the sea instead of being the 

 causes of its saltness ; and the deliquescent salts have become concen- 

 trated, as in modern estuaries, into the still liquid part that constitutes 

 a mother-water fully comparable in all respects to the mother-waters 

 of the salt-marshes of the south of France. 



I conclude with a summary of the principal facts to which I have 

 directed attention. 



At the moment when the first crust of consolidation began to form 

 around our globe, chlorine and sulphur, now existing in combinations, 

 were in the atmosphere. When the temperature had sufficiently dimin- 

 ished, these two bodies, reacting on the exterior crust of our globe, 

 formed, at intervals otherwise extremely distant, combinations (sul- 

 phates and chlorides) by uniting with the metals that existed and 

 still exist in the rocks constituting that first envelope. These metals, 

 combined almost exclusively with sulphur and chlorine, are precisely 

 the ones (lithium, potassium, sodium, magnesium, calcium) that still 

 mineralize the waters of the seas. The salts thus formed, dissolved in 

 the waters from the most ancient age of the aqueous period of our 

 planet, have, then, a wholly exterior origin. Later, under the influence 

 of causes often extremely insignificant in themselves, parts of these 

 seas have been isolated from the oceans ; they have evaporated, and, 

 according to the degree of completeness in which concentration has 

 been effected, they have deposited salt-beds sometimes of a complex 

 enough nature, but which have uniformly presented the typical char- 

 acter that they begin with deposits of gypsum. Such is the origin of 



