IN CERTAIN MINERAL WATERS OF SOUTH BRITAIN. 
225 
of the irritating effects of its vapour tends fully to confirm, I cannot view it as 
absurd to trace the medical virtues ascribed to such waters as those of Ashby- 
de-la-Zouch, to the presence of even so small a quantity as a grain of hydro- 
bromate of magnesia (if such be the combination) in each pint of the water ; 
and that the proportion would not fall far short of that, my experiments on this 
particular spring seem to warrant me in concluding. It is curious at least, 
that almost the only two brine-springs, properly so called, which have acquired 
any reputation as medicinal agents, that of Kreutznach in the Palatinate, and 
that of Ashby-de-la-Zouch in Leicestershire, both should contain a larger pro- 
portion than common of this new principle ; and that in either instance that 
reputation should have been enjoyed, long before any suspicion as to their 
peculiar nature could have been entertained. 
The objects I had in view in this inquiry being what are above stated, I 
have chosen to classify the springs noticed in the accompanying Table accord- 
ing to the geological position of the strata from which they issue ; and under 
the head of each have set down the total amount of their saline ingredients ; 
the nature and proportion of them as ascertained by former chemists, or, 
whenever I could not depend upon the results, by myself ; and the proportion 
which the iodine and bromine, where either of these principles existed, bore to 
the quantity of water, and likewise to that of the chlorine which the solid 
ingredients of the spring might contain. The latter statement has been intro- 
duced in order to remove an impression which may have been created in con- 
sequence of the detection of iodine, as it is said, even in common pump-water*, 
when very large quantities of it were evaporated ; from which circumstance it 
might be inferred, that this principle is not only a constant accompaniment of 
common salt, but that its quantity bears a pretty regular ratio to that of the 
latter ingredient. Although I have myself evaporated no less than forty-eight 
gallons of the Oxford pump-water without finding the slightest trace of iodine 
in the last portions, I shall not dispute the truth of the former position, which 
might possibly have been borne out, had still larger quantities been operated 
upon 'I' ; but that the latter opinion is untenable, will be readily seen from the 
* Mr. Cuff, a chemist at Bath, has also detected it in the hot springs of that place, by evaporating 
about thirty gallons of the water. 
t I am also loth to question the fact (stated on good authority) of the existence of a minute pro- 
2 g 2 
