lSGc".] CHEMISTRY OF NATURAL WATERS. 283 



much less than in the waters of the modern seas. According to 

 Usiglio, 100 parts of the salts from the Mediterranean contain 

 1-48 of broraid of sodium ; while ten analyses by Yon Bibraof the 

 waters of different oceans, give from 086 to 1-46, affording for 

 100 parts of salts, a mean of 1*16 of bromid of sodium, equal to 

 1*04 parts of bromid of magnesium. The waters of Whitby and 

 Hallowell, on the contrary, which are the richest in bromids of 

 those described in this paper, contain only 54 and 89 parts of 

 bromid of sodium in 100 parts of solid matters; while few of the 

 saline springs of the second class contain more than one-half of this 

 propoition, and some of them very much less. 



With regard to the iodids in many of these waters, however, the 

 case is very different. The waters of the modern ocean, as is well 

 known, contain but traces of iodine, and in some strongly saline 

 springs of the first class, like that of Whitby, it is only in the 

 alcoholic extract of the salts from this water that iodine can be 

 detected. The Hallowell water (§ 36, No. 3), which closely 

 resembles this in its general composition, and in the proportion of 

 bromids, is however so rich in iodine that its presence can readily 

 be discovered without previous evaporation. It is sufficient to 

 add to the recent water acidulated by hydrochloric acid, a little 

 solution of starch, and a few drops of nitrite of potash to produce 

 an intense blue color. The iodid of sodium in . the first-named 

 water was found equal to 0-0017 parts of the solid matters, and 

 that of the second to 0-019 or nearly twelve times as much. The 

 unconcentrated saline waters of Ste. Genevieve, of the second class, 

 also give a strong re-action for iodine, and when acidulated with 

 hydrochloric acid, without previous evaporation, yield with a salt 

 of palladium an insoluble precipitate of iodid of palladium after 

 a few hours. The salts from these two springs of Ste. Genevieve, 

 though poorer in bromids, are much richer in iodids than the 

 waters of Hallowell; the spring No. 8, containing in 100 parts of 

 salts no less than 0-138 of iodine, so that there appears to be no 

 constant proportion between the chlorids, bromids, and iodids of 

 these saline waters. 



§ 60. The relations of bromids and iodids to argillaceous 

 sediments have yet to be determined. It would appear from the 

 facts just cited that bromine has in the course of ages been slowly 

 eliminated from insoluble combinations, and like potassium, has 

 accumulated in the waters of the ocean ; while the facts in the 

 history of iodine seem to point to a process the reverse of this ; 



