"
Those nodular bodies or figured parts which are here inclosed in the
rock, are evidently what may be called calcedony agates. M. Patrin is
persuaded, from the examination of them, that they had not been formed
in the manner of German agates, which he supposes is by mean of
infiltration; and he has endeavoured to conceive another manner of
operating, still however by means of water, which I suppose, according
to this hypothesis, is to dissolve substances in one part, and deposits
them in another, There must certainly be some great _desideratum_ in
that mineral philosophy which is obliged to have recourse to such
violent suppositions. First, water is not an universal solvent, as it
would require to be, upon this supposition; secondly, were water allowed
to be an universal menstruum, here is to be established a circulation
that does not naturally arise from the mixture of water and earth; and,
lastly, were this circulation to be allowed, it would not explain the
variety which is found in the consolidation and concretion of mineral
bodies.
So long, therefore, as we are to explain natural appearances by
reasoning from known principles, and not by ascribing those effects to
preternatural causes, we cannot allow of this regular operation which
M.
Pages:
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497