The difficulty of solution in the vegetable astringents has been complained of by various writers on the _Materia Medica_. Water and alcohol are the menstrua in use; but great quantities of each are necessary to procure even a slight impregnation, and much heat and long boiling are said actually to destroy the astringent quality, and vegetable texture.[t] As a menstruum capable of dissolving them with greater facility appeared to be a desideratum, not only in pharmacy, but in other arts, particularly in that of dying blacks, I resolved to try Dr. Macbride's method of increasing the solvent power of water, by means of quick-lime. But as I was aware that the quantity of lime he made use of in obtaining an aqueous tincture of Peruvian bark, would be too great for the dyer's use, I wished to use only such a quantity as would be sufficiently saturated with the air contained in the vegetable, to be itself precipitated; and to compare the tinctures thus made, with a standard prepared with simple water. [t] Vid. Lectures on the Materia Medica, as delivered by William Cullen, M.D. p. 195. EXPERIMENT XV. I rubbed three drachms of Aleppo galls reduced to powder, with four ounces of filtered rain water, for fifteen minutes, and then passed the solution through paper. It was very styptic to the taste, and was nearly of the same colour as Huxham's tincture of bark. The residuum in the filter was unchanged in colour. The bottle containing the liquor was marked number 1. EXPERIMENT XVI. Three drachms of the same galls, and two scruples of quick-lime, were triturated with four ounces of rain water, as in the last experiment. The filtered liquor had scarcely any astringency to the taste, and was of a very pale colour. The residuum was of a deep purple. Marked number 2. EXPERIMENT XVII. The same quantity of galls as in the two former experiments, after triture in the same degree with four ounces of lime-water, was separated by filtering through paper. The tincture thus obtained was highly astringent to the palate, of a deep chocolate colour, and the residuum was of a lighter brown than number 1. Marked number 3. EXPERIMENT XVIII. To each of the above tinctures were added forty drops of a strong solution of sal martis. Number 1 became very black. Number 2 changed colour but little, and on standing precipitated a brown sediment, which, the superiour part of the liquor being decanted off, became again transparent on the addition of a few drops of the vitriolic acid. Number 3 appeared to strike a deeper black than number 1; and these being tried as inks, number 3 seemed to have the superiority; but a slip of linen cloth being macerated in each for some hours, that in number 1 had taken a more perfect black than the slip number 3. No trial was made with cotton or woollen, which it is probable would have differed from the linen. EXPERIMENT XIX.