OLIVEE: MINEEAL SPEINGS OF THE WEST EIDING. 351 
hood of the Chloride of Iron well ? But this view must appear 
doubtful when we consider what a large quantity of barium chloride 
it necessitates — very much larger than has yet been met with in, or 
is likely to be furnished to the issues of a mineral water ; and when it 
is remembered that, notwithstanding the repeated periodical scrutiny 
of the water during the past twenty years, iron sulphate has never 
been found as a constituent. Still in the course of time, as fresh 
evidence may accumulate, it will be well to keep in mind this 
possible origin of the ferrous chloride, for in the other springs (only 
two) in Europe in which it has been met with — namely Alexisbad 
and Buckowina — Ferrous sulphate has been discovered, and in 
Buckowina alum also. This ferrous chloride well of Harrogate is, 
therefore, the only water of similar composition at present known 
that does not contain sulphates. 
(2) Deposit of Ferrous Chloride. — In the remarkable saliferous 
deposits of Strassfurt,* ferrous chloride has been found associated 
with potassium chloride (FeClg 2KC1 + 2 HgO).! At present this 
observation may seem devoid of obvious bearing on this difficult 
question : but as enquiry advances it may possibly provide a link in 
the chain of evidence. With the same view I will merely mention 
the yellow masses of perchloride of iron found so abundantly in the 
openings and clefts of fumeroles and in the interior of craters, and 
the reduction of this ferric salt to the condition of protochloride in 
the presence of sulphuretted hydrogen. In the absence of positive 
evidence of volcanic action — unless the disturbed strata be accepted 
as such — we can but speculate on the mere possibility of some 
volcanic products having been intruded into the formations of aqueous 
origin. 
Such are a few of the debateable questions raised by the con- 
stituents of these waters. Though they show you the difficulty of 
tracing with any degree of probability the sources of mineralization, 
they nevertheless, when studied with due caution, may suggest to 
the geologist open to all available evidence, interesting facts and 
matter for speculation that cannot be gleaned by direct observation. 
* The different salts are stratified according to their solubiHties. 
t Journal of the Chemical Society ^ May, 1881. 
