Experiments and observations to investigate the composition of James's powder / [George Pearson].

  • George Pearson
Date:
[1791]
Catalogue details

Licence: Public Domain Mark

Credit: Experiments and observations to investigate the composition of James's powder / [George Pearson]. Source: Wellcome Collection.

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    water. M. Fourckoy also says, he found magnesia in the intestinal calculus of a horse; which calculus was a triple com- bination, of one part of phosphate of ammoniac, two parts of magnesia, and one of water, besides traces of animal and vegetable matter. Dr. Link, in a very elaborate dissertation, published at Got- tingen, in 1788, on urine and calculi, concludes that urinary concretions consist of phosphoric acid, lime, ammoniac, oil, the bases of different kinds of gazes, together with the acid sublimate of ScJheele, although he did not succeed in obtaining it. It is a proof of Dr. Black’s sagacity, that he should have been able to perceive, from a few experiments, that urinary concretions consisted of animal matter and the earth of bonp, before the composition of this earth was demonstrated by Gahn. In this historical sketch it should be noticed, that alkaline substances, though used by the Greek physicians, and after- wards by the alchemical physicians, appear to have been laid aside by the regular practitioners, for a century or two prece- ding their revival, by the famous Mrs. Stephens, in 1720. Her prescription brought into vogue the theory of these me- dicines operating by their causticity. The successful use, by Mr. CoLBORNE, of potash saturated with carbonic acid, ac- cording to the discovery of Bewley and Bergman, and the still further improvement in practice, from the use of soda, as well as potash, super-saturated with carbonic acid, by the dis- covery of a peculiar method by Mr. Schweppe, have com- pletely refuted the theory of the agency of alkalies on the principle of causticity. It appears, from the preceding brief history, as well as from the confession of the latest and best writers, that the experi-