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THE GEOLOG-Y OF MIHEEAL SPEIHGS. 
BY FEANCIS T. BOND, M.D., B.A., F.C.S., 
PRINCIPxM. OF THE HAP.TLEY IHSTITUtIoH, SOUTHAMPTON. 
K > * 
I T is a favourite subject of speculation with many persons^ 
who are rather dis230sed to occupy themselves with the 
ideal than the practical side of life_, to seek compensation for 
the imperfections and drawbacks inherent to things as they are, 
by imagining them as they might have been. Any of our readers 
who may have a disposition in this direction_, and who, at the 
same time, may be liable to an occasional fit of unphilosophical 
irritation from these periodical irregularities of water-supply, 
which are by no means infrequent, even under the auspices of 
the best-regulated water companies, may possibly derive some 
consolation under their grievances from the contemplation of 
the condition in which they might have found themselves when 
they were thirsty if the geological conformation of the earth 
had been otherwise arranged than it is. Should they, more- 
over, indulge at times in the habit of forsaking the stream 
which springs spontaneously in their own back yard for the 
meretricious attractions of Homburg, Kissingen, Schwalbach, 
or any of the other localities whose healing waters are 
periodically troubled for the benefit of the valetudinarian crowd 
vHo frequent them, they may, perhaps, feel an additional 
incentive to investigate, in a cursory manner, the causes to 
which they owe alike these health-giving fountains and their 
humbler rival, the domestic pump. 
At the present time, when the schoolmaster has got so far 
^^abroad^^ that one begins to wonder whether he will ever find 
his way home again, every one is sufficiently familiar with the 
elementary facts of geology to be aware that the eartffis crust 
is composed, in a great measure, of a series of strata, lying 
over one another like the coats of an onion, which have been 
formed by the successive depositions of sedimentary matter 
that have taken place in the seas and lakes of former ages. 
But, from the habit which geological diagram-makers have of 
representing these strata, generally as superimposed horizon- 
tally upon another, many people are not aware, or, if aware, 
are sometimes apt to forget, that although theoretically, and on 
