Elements of the art of assaying metals. [electronic resource] : In two parts. The first containing the theory, the second the practice of the said Art. The Whole Deduced from the true Properties and Nature of Fossils; confirmed by the most accurate and unquestionable Experiments, explained in a natural Order, and with the utmost Clearness. Written originally in Latin, by John Andrew Cramer, M.D. With notes and observations not in the Original, particularly Useful to the English Reader. By Cromwell Mortimer, M. D. Secretary to the Royal Society. To which is prefixed A List of the Chief English Authors who have written upon Minerals and Metals.