REPORT ON MINERAL AND THERMAL WATERS. 



17 



siderable quantity of common salt, which are distributed through 

 the several rocks of this country, beginning my search with the 

 Silurian formations of Wales, and terminating it with the ter- 

 tiary deposits of the London basin. 



In the tabular view of the constituents of these springs given 

 in the paper I presented to the Royal Society * on that subject, 

 and which is now published in their Transacfions, I showed, 

 that although the proportions of the respective ingredients might 

 vary, yet that as regards their quality, an almost entire corre- 

 spondence must have obtained between the earliest accumula- 

 tions of salt water and the existing ones, judging from the occa- 

 sional presence of iodine and bromine in those of all ages. 



Thus both these jirinciples were found in waters issuing from 

 the Silurian slates of Llandrindod and Bualt in Hadnorshire, 

 and bromine, but not iodine, in those from the coal formation 

 of Ashby de la Zouch, Newcastle-on-Tyne, and Kingswood. 

 Both principles exist in the springs issuing from lias, at Leam- 

 ington, Gloucester, Tewkesbury, and Cheltenliam ; whilst in 

 the aperient saline waters of Melksham, Epsom, and London, all 

 of which are connected with newer rocks, iodine appeared to be 

 altogether wanting, though traces of bromine were detected. 



It remains to be ascertained by a more extensive induction of 

 particulars than that hitherto made, whether iodine is commonly 

 deficient in springs connected with the more recent deposits ; as 

 such a fact, combined with that of its scanty occurrence in our 

 present seas, and its comparative abundance in strata of older 

 date, might lead to some curious geological inferences. 



The proportion of iodine to water in different springs, I found 

 to vary from gj^^ to ^j ^-'g gQ„ partj and to the chlorine present 

 in it from 



614,400 



to 



2,000,000 



21,0/3,900 



part. 



In several of the German springs, however, the proportion 

 appears to be much larger f. Thus, there have been "found, in a 

 pint of the salt spring of 



In the springs I examined, the proportion of bromine to 

 water varied from ^ to 73^9 part, and to the chlorine from ~ 



to 1660" 



* Philosophical Ti-ansactions, 1830. 

 t Osann, Ueber led- und Broin-haltige Min. Qmllen. 

 VOL. v.— 1836. c 



