IN CERTAIN MINERAL WATERS OF SOUTH BRITAIN. 
229 
farther labours on this subject not be rendered in the mean time unnecessary 
by the investigations of some other chemist. In cases where the quantity of 
this principle appeared to be less considerable, as in the Leamington, Chel- 
tenham, and Gloucester waters, I have contented myself with guessing at its 
proportion by concentrating the water until it assumed a decidedly yellow 
tinge with chlorine, noting what proportion of bromine in water produced a 
colour of equal intensity. 
The earliest of the rock-formations in this country that come under our con- 
sideration with reference to the present inquiry, is the greywacke slate of 
North Wales, which in the neighbourhood of Bualt in Radnorshire gives out 
springs containing a notable proportion of common salt. Those of Llandrindod 
have long enjoyed some reputation as medicinal agents, but their composition 
does not appear to have been correctly ascertained ; for the most modern 
analysis I have seen* assigns to them a considerable proportion of muriate of 
magnesia, of which I find scarcely a trace. The more newly discovered springs 
at Bualt itself, though less celebrated, are similar in point of constitution ; 
and being double the strength of those of Llandrindod, ought to possess 
superior medical virtues. At both places are waters which differ from the rest 
in containing an unimportant impregnation of sulphuretted hydrogen, but in 
other respects correspond. 
Many of our coal-pits emit streams of salt water ; but the most remarkable 
spring of the kind is that already noticed, of Ashby-de-la-Zouch in Leicester- 
shire, which for the last few years, especially since the erection of the baths, 
which are now so great an ornament to the spot, has acquired a certain local 
reputation in the cure of diseases. Previously to the discovery of bromine, of 
which I detected in this water an appreciable quantity. Dr. Thomson of Glas- 
gow had examined its composition ; and I have therefore been satisfied with 
adhering to the results of his analysis, which is stated in the Table. 
The most important, however, of the salt-springs that we meet with in this 
country are those in the new red sandstone formation of Cheshire ; for an 
analysis of which I may refer to a paper of Dr. Henry’s, published in the 
Transactions of this Society. In this instance, also, I have adopted the state- 
ments of another, merely making a proportionate deduction from the amount 
* Analysis of the Llandrindod Waters; by Mr. Williams, Surgeon, 1819. 
