136 Some Experiments upon the Pod of 



nica, nutgalls, tormentilla, pomegranate rind, and sumach. I 

 regret that I have not yet had time to compare it with many 

 others, which a future opportunity may enable me to do. As 

 these experiments, if repeated, might be expected to vary in the 

 resuh from many causes, such as the season of gathering the 

 fruit ; the temperature of drying the powder and the precipi- 

 tates ; the degree of comminution ; the difference of weights and 

 errors of scales ; the time of maceration, and temperature at 

 which it is conducted ; the care in decanting ; the fineness of 

 the filter; the caution used to collect all the precipitate, and the 

 waste in transference from paper to paper ; and, as the substances 

 submitted to experiment are not crystalline, or naturally of an 

 invariable composition, I have not used much precaution or 

 great nicety in weighing, my object being rather to form an idea 

 of the use of dividivi, than to analyse all the substances with 

 accuracy. 



, 3. One drachm, or 60 grains of each of the substances before 

 mentioned, and in the state of powder, was macerated for forty- 

 eight hours, in 5 oz., or forty times its weight, of cold distilled 

 water. The first elutriation, the colour of which is seen in 

 column 1, was used in the subsequent experiments; the sedi- 

 ments were afterwards repeatedly rernacerated in more water, 

 and, when dried in a gentle heat, weighed as in column 2, the 

 water having dissolved as many grains, expressed in column 3, 

 as complete the original drachm. 



4. The first substance, the action of which I made upon these 

 astringents, I made trial of was Ume-zvater. To three ounces of 

 fresh prepared lime-water I added half an ounce, or one-tenth 

 of each infusion, containing the virtue of six grains of its basis ; 

 the result is contained in columns 4, 5, and 6. The first shews 

 the colour, and the second the weight of each precipitate ; the 

 liquors decanted from the above precipitates having the colours 

 mentioned in column 6, as well as 



5. The original infusions were tested with muriate of iron, 

 the result appears in columns 7 and 8 ; and, in order to see 

 whether the lime-water had been used in sufficient quantity, I 

 tried with the original infusions the different lime-water elutria- 

 tions with the result indicated in column 9. The result of these 

 experiments is, that the lime-water was used in excess, but did 



