] 38 Some Experiments upon the Pod of 



feet, but lime-water but very little. The decoction of isinglass 

 produced no effect with the elutriation of lime, not even with 

 that of catechu. 



9. Irrftision of quassia produced no effect upon any of the as- 

 tringent infusions above mentioned. 



10. Sugar of lead turned the different infusions, as in column 

 14 ; with the infusions of oak and sumach it was not tried. 



11. I next tried sulphates of copper, I perceived but little 

 effect, and sometimes none, with the persulphate, but the proto- 

 sulphate gave very curious results, see columns 15 and 16. 

 The precipitates, however, were not weighed nor preserved. 



12. Muriate c^tin was the next test used. The comparative 

 copiousness of the precipitates, after twelve hours'* standing, may 

 be seen in column 17, which contains the depths of precipitate, 

 in the infusion. Column 18 contains the weight of each. Af- 

 ter the action of the muriate of tin, muriate of iron affected 

 some infusions, and not others, according to column 19 ; but 

 muriate of tin itself produced no effect, shewing it had been used 

 in excess : this likewise appeared from adding more infusion, as 

 indicated in column 20; when the elutriation from muriate of 

 tin was tried with isinglass, no effect was produced. I observed 

 ammonia to turn violet, the elutriation from muriate of tin and 

 galls. 



13. Emetic tartar produced no effect upon any of the infu- 

 sions. 



14. From columns 4, 8, 12, 16, and 19, dividivi appears 

 more to resemble, in its properties, gall and sumach, than the 

 other astringents ; but, from columns 6, 9, 11, 13, 15, 18, and 

 20, it seems to differ more from sumach than from galls. It 

 entirely resembles galls, except in the effect of subcarbonate of 

 potash and isinglass, apparent from the galls, containing another 

 principle common to them and sumach : see columns 10 and 

 12. From column 18 it would appear to be equal in strength 

 to nut-galls, and, from columns 5 and 13, considerably stronger. 



15. I next proceed to prepare, from both dividivi and galls, 

 some ink-powder, according to Mr Gray's formula, and the 

 writing from each was indistinguishable the one from the other. 

 It has been asserted, and probably with truth, that the durabi- 

 lity of ink bears some ratio to the proportionate quantity of nut- 



