(J70 PHILOSOPHICAL TRANSACTIONS. [aNNO I78O. 



Exper. 43. To the aquafortis which had been digested with the ashes, some 

 vitriolic acid being added, the liquor immediately became turbid, and selenitic 

 particles were precipitated: whence it appears that the ashes contained some un- 

 combined calcareous earth. The selenitic particles being separated by filtration, 

 and the liquor being afterwards evaporated, it left no solid matter behind. 



Exper. 44. The portion of ashes which was not dissolved by the nitrous acid, 

 after being edulcorated and dried, weighed 2 dr. On this I oz. of oil of vitriol 

 was poured; it was then subjected to a strong heat until all the fluid was driven 

 off, and was afterwards boiled in distilled water. This liquor being filtrated and 

 evaporated, it yielded small crystals, tasting like alum, and letting fall a 

 precipitate on the addition of an alkali. 



Exper. 45. The edulcorated and dried residuum being mixed with an equal 

 quantity of mineral alkali, and being afterwards melted in a crucible by a strong 

 heat, it yielded a very good transparent glass. Dr. C. next proceeded to examine 

 the nature of the acid and its action on other bodies. 



Exper. 46. He distilled with a gentle heat the acid of exper 10. What came 

 over was of a whitish colour inclining to yellow; there remained at the bottom 

 of the retort an unctuous coally residuum. The attempt to dephlegmate the 

 acid by distillation in a gentle heat, proved ineffectual; the liquor in the 

 receiver was found equally acid with that in the retort. 



Exper. 47. The salt formed by the combination of this acid with the veget- 

 able fixed alkali, has been already mentioned under exp. 12. That formed with 

 the mineral alkali is here described. It took 5 oz. of the acid of exper. 46 to 

 saturate 3 dr. of the crystallized mineral alkali. This solution being evaporated 

 to a cuticle, it yielded brown-coloured crystals, which were afterwards put into 

 a crucible and fused in a moderate degree of heat, until they ceased to emit any 

 vapour, or smoke. The saline mass was then dissolved in water, and the solu- 

 tion being evaporated to the point of crystallization, it afforded cubic 

 crystals, terminating for the most part in triangular pyramids. On exposure to 

 the air these crystals became covered over with a white mealy powder. 



Exper. 48. The salt formed by the union of this acid with the volatile alkali 

 sublimed, in the form of white flowers, in the same degree of heat at which 

 common sal ammoniac sublimes. 



Exper. 49. This acid dissolved calcareous earth with much effervescence. 

 Two dr. of the acid were sufficient for the saturation of J 1 dr. of this earth. 

 The same salt was prepared by mixing suet with pulverized quick lime, then 

 melting the mixture in a gentle heat, and afterwards boiling it in water. The 

 filtrated and evaporated liquor concreted into a saline mass. The experiment 

 succeeded better when a mixture of suet and quick lime was subjected to distil- 

 lation. The lixivium being evaporated to a due consistence, it afforded crystals 



