Experiments and Observations on the Following Subjects / 1. On the preparation, calcination, and medicinal uses of Magnesia Alba. 2. On the solvent qualities of calcined Magnesia. 3. On the variety in the solvent powers of quick-lime, when used in different quantities. 4. On various absorbents, as promoting or retarding putrefaction. 5. On the comparative antiseptic powers of vegetable infusions prepared with lime, &c. 6. On the sweetening properties of fixed air.

by Thomas Henry

EXPERIMENT X.

Five grains of camphor were rubbed for five minutes with an equal quantity of calcined Magnesia: after the camphor was reduced to powder, it united into a hard concrete with the Magnesia, but immediately dissolved on the addition of a small quantity of distilled water, of which an ounce was mixed with them, and immediately passed through filtering paper. The filtrated liquor was highly impregnated with the camphor.

EXPERIMENT XI.

Five grains of opium triturated in the same manner, yielded a transparent tincture, of as deep a colour as the tinctura Thebaica of the London Dispensatory, and tasting strongly of the opium.

EXPERIMENT XII.

Gum guaiacum and calcined Magnesia, of each a scruple, being rubbed with an ounce of water, and filtered, gave an elegant green tincture, quite transparent, and possessing, in a considerable degree, the taste of the gum.

Gum galbanum, storax, mastick, myrrh, assafætida, scammony and balsam of Tolu, being severally triturated with equal weights of calcined Magnesia, diluted with water and filtered, afforded neat tinctures, strongly impregnated with the different drugs.

EXPERIMENT XIII.

In order to determine the quantity of opium thus dissolved, half an ounce of crude opium, the same quantity of calcined Magnesia, and eight ounces of distilled water were rubbed for a quarter of an hour in a glass mortar, and having stood to infuse during two hours, the liquor was separated through paper. The tincture was of a darker colour than that before described, and was reduced by a gentle heat to a pilular consistence. This extract weighed sixty-eight grains, which, allowing for impurities, for what would be dissipated in evaporation, and for the air probably absorbed by the Magnesia, is a large proportion to be so soon dissolved. The residuum which was left in the filter was dried, and weighed six drachms.