“Cela ressemble en grand a ce qu’on observe dans les pierres oeillees, et la cause est vraisemblablement la meme.  Je le repete, je regarde cette disposition reguliere comme une veritable cristallisation, qui peut s’operer et qui s’opere en effet dans l’interieur des corp les plus solide, tant qu’ils sont fournis a l’action des agens de la nature.

“Tous ceux qui visitent l’interieur de la terre savent que les roches memes le plus compactes y sont intimement penetrees d’humidite, et ce fluide n’est certainement pas l’eau pure; c’est l’agent qui opere toutes les agregations, toutes les cristallisations, tous les travaux de la nature dans le regne mineral.  On peut donc aisement concevoir qu’a la faveur de ce fluide, il regne, dans les parties les plus intimes des corps souterrains, une circulation qui fait continuellement changer de place aux elemens de la matiere, jusqu’a ce que reunis par la force des affinites, les corpuscules similaires prennent la forme que la nature leur a assignee.”

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. Patrin alleges to be acting in the interior parts of the most solid bodies.  This is indeed evident, that there has been a cause operating in the internal parts of the most solid bodies, a cause by which the elements, or constituent parts of those solid bodies, have been moved and regularly disposed, as this author very well observes must have been the case in our agates or eyed stones; but to ascribe to water this effect, or to employ either an ineffectual or an unknown cause, is not to reason philosophically with regard to the history of nature; it is to reason phantastically, and to imagine fable.