[4] Mr. _Margraaf_ has lately demonstrated, by a set of curious and accurate experiments, that this powder is of the nature, and possesses the properties, of the gypseous or selenitic substances. That such substances can be resolved into vitriolic acid and calcarious earth, and can be again composed by joining these two ingredients together. Mem. de l'Acad. de Berlin. an. 1750, p. 144. [5] Hoff. Op. T. iv. p. 480 & 500. [6] Mem. de l'Acad. de Berlin. an. 1748, p. 57. [7] Hoff. Op. T. iv. p. 480. [8] This evaporation was performed in a silver dish, on account of the acrimony of the salt; which is so very great, that, having once evaporated a part of the same ley in a bowl of English earthen or stone ware, and melted the caustic with a gentle heat, it corroded and dissolved a part of the bowl, and left the inside of it pitted with small holes. [9] Mem. de l'Acad. de Berlin. an. 1746, p. 87. [10] Boerh. Operat. Chem. process. LXXVI. Transcribers Notes: 1. Author's spelling has been retained. 2. Minor punctuation issues have been corrected without note.