10 On the Valley of the Jordan and the Dead Sea. 



and four upon the west, must go off by evaporation, by some sub- 

 terranean channel, or more probably by both united. The pre- 

 cipitation of salt to the bottom during the summer months, in con- 

 sequence of the great evaporation, must we presume be consid- 

 erable. 



(5.) Specific gravity. The water of the Dead Sea has been 

 frequently analyzed by European chemists, the varying results of 

 whose experiments — a difference easily explicable by those who 

 understand the disturbing influences affecting the lake — have only 

 increased the necessity of multiplied examinations, in order to 

 furnish an intelligible approximation to a correct average. 



For the subjoined analysis of a portion taken from the lake at 

 the time of my visit, April 18, 1843, I am indebted to the kind- 

 ness of Mr. B. Silliman, Jr.* 



The portion here analyzed by Mr. Silliman, Jr., is, I believe, 

 the first ever experimented upon, this side of the Atlantic. It 

 was sealed up at the time of taking it, and so kept until my ar- 

 rival at home in November last, when immediately after opening, 

 it was again hermetically closed. I am thus particular in regard 

 to the time, since the season, owing to the more rapid evapora- 



* The water which Mr. Sherwood brought from the Dead Sea, and of which I 

 received a portion from him, had a specific gravity of !• 1509 on several trials; 

 being less than the least weight named in the four analyses quoted below, viz. 

 Dr. Apjohn's, 1153. It was neutral, having no effect on litmus, or Georgina 

 leaves. On boiling for some time, no insoluble deposit appeared, and no escape of 

 gaseous matter; evaporated to dryness at 212° to 220", it re-dissolved entirely in 

 pure water. Hence I infer the absence of carbonic acid and of bicarhonates. 



Paper prepared with acetate of lead remained unchanged, whence, as well as 

 from the foregoing, I infer the absence of sulphuretted hydrogen. Ammonia, alu- 

 mina, phosphoric acid, and iodine, were sought for in vain. A current of chlorine 

 gas passed through the water soon developed a fine brownish red color in the 

 fluid ; ether agitated with it took up all the coloring matter, and a solution of 

 caustic potash at once made it disappear from the ether. This was good evidence 

 of the presence of bromine. 



Dr. Daubeny (see Report on Mineral and Thermal Waters in the 6th Report of 

 the British Association, p. 47) has remarked in speaking of the constitution of 

 mineral waters — " that as the salts existing in a spring need not be the same with 

 those obtained on evaporation ; and as salts viewed as incompatible may co-exist 

 in a state of weak solution, the analysis of a mineral water consists in nothing more 

 than in determining the nature and amount of the several acids and bases which it 

 contains. But Berzelius has further contended, (in his analysis of the Carlsbad 

 water, Ann. de Chim. xxviii,) that every thing beyond this which the chemical 

 analysis professes to give, is a matter of hypothesis. He also says, and apparently 

 with much justice, that consistently with the views of Berthollet on the influence 

 of the mass, we ought to suppose as many salts to exist in a mineral water as can be 



