VOL. LXXXI.] PHILOSOPHICAL TRANSACTIONS. 105 



and which, when the bottle was hastily inverted, fell through the spirit of wine 

 in round drops, like a ponderous oil. The supernatant spirit of wine being 

 carefully decanted off, some distilled water was added to this thick fluid, by 

 which it was wholly dissolved. This solution, exposed to the air, showed phe- 

 nomena exactly similar to those of the undiluted solution (d). The decanted spirit 

 being also left exposed to the air in a shallow glass vessel, did not, after many 

 days, either deposit a sensible quantity of precipitate, or become gelatinous; 

 but having evaporated nearly away, left a few drops of a liquor which made 

 infusion of red cabbage green ; and on the addition of some pure marine acid, 

 effervesced violently. No precipitate fell during this saturation with the acid; 

 nor did the mixture on standing become a jelly ; and on the total evaporation 

 of the fluid part, a small quantity of muriate of tartar only remained. The 

 spirit of wine seems therefore to have dissolved merely a portion ot super- 

 abundant alkali present in the mixture, but none of that united with tabasheer. 

 (f) To different portions of this solution were added some pure marine acid, 

 some pure white vitriolic acid, and some distilled vinegar, each in excess. These 

 acids at first produced neither heat, effervescence, precipitate, nor the least 

 sensible effect, except the yitriolic acid, which threw down a very small quantity 

 of a white matter; but, after standing some days, these mixtures changed into 

 jellies so firm, that the glasses containing them were inverted without their 

 falling out. This change into jelly equally took place whether the mixtures 

 were kept in open or closed vessels, were exposed to the light, or secluded from 

 it; nor did it seem to be much promoted by boiling the mixtures, (g) Some 

 solution of mild volatile alkali in distilled water, being added to some of this 

 solution, seemed at the first instant of mixture, to have no effect on it; but in the 

 space of a second or 2 it occasioned a copious white precipitate, (h) The flakes 

 remaining on the glasses at (d) and (e) put into marine acid raised a slight effer- 

 vescence, but did not dissolve. These flakes, when taken out of the acid, and 

 well washed, were found, like the original tabasheer, to be white and opaque 

 when dry; but to become transparent when moistened, and then to show the 

 blue and flame colour, § 2. (a), (i) The jellies (f), diluted with water, and 

 collected on a filter, appeared to be the tabasheer unchanged. 



^ 10. A bit of tabasheer, weighing -i\ gr., was boiled in 127 gr. of strong 

 caustic volatile alkali for a considerable time; but after being made red-hot, it 

 had not sustained the least diminution of weight. 



^11. (a) 27 gr. of tabasheer, reduced to fine powder, were put into an 

 open tin vessel with 100 gr. of crystals of soda, and some distilled water, and 

 this mixture was made to boil for 3 hours. The clear liquor was then poured 

 off, and the tabasheer was digested in some pure marine acid; after some time 

 this acid was decanted, and the tabasheer washed with distilled water, which was 



VOL. XVII. P 



