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of Stones; as well the more precious, as the common: and of the various Earths of peculiar Kinds, whether remarkable for Colour, Smoothneſs, Denſity, or whatever other Quality.
to obſerve, that it was far from being either abſurd, or improbable, at the Time when he wrote; when the Sciences, to which the preſent Age owes its Improvements in Natural Knowledge, were ſo little underſtood; and ſo few of the Experiments, which have now given Light into it, had been made; and that it carries at leaſt, an equal Air of Probability, with many that have been ſince formed; and is abſolutely more ſuccinctly, clearly, and philoſophically delivered than any of them all.
The Principles of mixed Bodies, as well thoſe of the foſſile, as of the vegetable and animal Kingdoms, are indeed ſo intimately united, and cloſely combined together, at their original Formation, that we are not to wonder, an Author, who wrote in ſuch early Times, was not clearly acquainted with the exact Manner of their Compoſition: Thoſe who have followed him, even after the Diſcoveries of many ſucceeding Ages, and with the Aſſiſtance of Chemiſtry, the beſt and ſureft of all Means of judging, (and which, whatever ſome Men of fertile Imaginations may have thought, we have no ſound Reaſon to believe was much known in his Time) have yet been of late found to have run into great Errors about them: and even thoſe of the preſent and laſt Age, who have been able to diſcover the Miſtakes of theſe, and have the Advantage of yet greater and farther Improvements in that Science, if they will ſpeak frankly and ingenuouſly, muſt own, that though they have diſcovered the Errors of their Predeceſſors, and are certain they are nearer the real Knowledge of the Myſteries of Nature than thoſe of any other Age have been, they yet are ſenſible, that they are only making farther and farther Advances toward what, perhaps, it is not in human Nature ever perfectly to complete.
Chemical Analyſiſes, when judiciouſly and carefully made, are unqueſtionably the ſureſt and beſt Methods we can uſe, towards the
