Experiments researches, and observations,on the vitrous spar, or, Sparry flour [electronic resource] : Being, a compleat supplement to the discoveries made by the learned Mr. Scheele, of the Royal Academy of Stockholm; with the addition of various experiments and observations, which never occurred to Mr. Scheele. By that ingenious chymist and alchymist at Paris, M. Boullanger, R.S.S. translated into English from the author's manuscript, by Mr. Ph. D. G.M.D.