in Brine-Springs and in RocJc-Salt. 415 



rated water, in many respects strongly resembling that of the 

 Dead Sea, of the Lake Ourmia, or Lake of Shahee, in Persia, 

 Phil. Trans. 1819, p. 194. 



In the Phil, Mag. and Annals, N. S. vol. ii. p. 232, will be 

 found the results of C. G. Gmelin's analysis of the water of the 

 Dead Sea, which he states to contain 1*6738 per cent of chlo- 

 ride of potassium, without mentioning sulphate of potash. 



A train of research instituted for the purpose of ascertaining 

 whether all the saline constituents of sea-water are to be 

 found, and in the same proportions, respectively, in rock-salt 

 and in brine-springs, would be of great interest in a geological 

 point of view ; since, although obvious inference and many cir- 

 cumstances attending the deposits of rock-salt refer their origin 

 to the ocean, yet there are difficulties affecting the most plau- 

 sible theories of their formation, which a minute comparison 

 of the constituents of rock-salt, &c., with those of sea-water, 

 would probably tend to remove. 



The quantity of sulphate of potash which Dr. Wollaston 

 found in sea-water, by an approximative method, is in the pro- 

 portion of 2-163 per cent of the total quantity of sahne matter 

 contained in it*. Now this quantity differs only 0'362, in de- 

 fect, from that assigned by Dr. M'^Neven to the entire salt of 

 Salina; and it differs only 0*172, in excess, from the propor- 

 tion of the same salt in the evaporated Droit wich brine, as- 

 suming the excess of sulphuric acid detected by Mr. Horner 

 to exist in it in combination with potash. This near accord- 

 ance, perhaps, may be regarded as confirmatory of the truth 

 of that assumption. 



It is probable that the potash in sea-water does not arise 

 exclusively from the source suggested by Dr. Wollaston, since 

 that alkali is a constituent, and in no inconsiderable propor- 

 tion, of the oldest rocks. But even if we should prefer to ascribe 

 its presence in sea-water wholly to the decay of plants, stili 

 there is no difficulty in conceiving its introduction, by the same 

 means, into the waters of the primaeval ocean, from which, by 

 whatever operation of nature, and whatever changes may sub- 

 sequently have been induced, the beds of rock-salt must ori- 

 ginally have been deposited. For we know that land and 



* Dr. Wollaston found sea-water of the specific gravity of 1026-2i? to 

 contain about -pV,^ of sulphate of potash. (Phil. Trans. 1819, p. 201.) And 

 from Dr. Marcct's experiments (lb. p. 202) it will be found that sea-water 

 of this density must contain ID'SS grains of saline matter in 500 of the 

 water. 



Now yV-'„'v = 0'417 very nearly, which is the quantity of sulphate of 

 potash contained in ."jOO f^rains of sea-water, or in the 19'28 grains of saline 

 matter which they hold in solution. Therefore as lf)-28 : 0417: : 100 : 2-l()3. 



fresh- 



