VOL. XLI.] PHILOSOPHICAL TRANSACTIONS. 367 



Exper. 10. — Thrown upon red coals, it did not crepitate like sea-salt, but 

 it boiled and swelled, and after evaporating it dried up. 



Exper. 1 ] . — It is of a very pungent taste, strongly pricking the tongue, 

 and of a bituminous smell of brimstone, which occasions a violent head-ach 

 by its volatile texture. 



Exper. 12. — The salts taken from different stones are not all of the same 

 weight or colour : for some are yellow and unctuous, as if rubbed all round 

 with petroleum : others are very white, others blackish, and others of other 

 colours, according to the stones they adhere to. 



Exper. 13. — I have likewise found by experience, that the sal ammoniac of 

 Vesuvius is much more efficacious, than any other salt known at this day, in 

 cooling liquors. On dissolving some of it in water, it makes the water so cold, 

 that the sides of the vessel which contains it, can hardly be touched without 

 uneasiness, through the excessive cold. 



Exper. 14. — Mons. GeofFroy, a celebrated member of the Academy of 

 Sciences, thinks it a singular power of common sal ammoniac, that being 

 mixed with a certain quantity of water, it rendered the water so cold, that 

 it made the spirit of his thermometer, 18 inches high, fall 33 lines. But the 

 Vesuvian salt makes the liquor of a thermometer, like his, fall 44. inches ; 

 which is equal to 54 lines. So that the efficacy of this salt, in causing the fall 

 of the liquor, exceeds the efficacy of common sal ammoniac by 21 lines. 



Exper. 15. — If round a vessel full of water cooled with snow, there be put 

 some of the salt of Vesuvius, the water freezes and grows hard in a very 

 little time. 



Exper. 16. — If a good quantity of the salt of Vesuvius be put into snow, 

 set round a glass vessel full of water, and then stir the vessel, the contained 

 water becomes unfit to drink ; having acquired a very disagreeable acrid sul- 

 phureous taste; a manifest sign, that the salt is divided into small particles, 

 which passing through the insensible pores of the glass, enter into and mix 

 with the water. 



Exper. 17. — Of all kinds of salts, this dissolves in the greatest quantity in 

 water; and perhaps the greater or less solubility of a salt in water, will be 

 found proportional to its greater or less effiict in cooling water. 



Exper. 18. — Being put into brandy, or oil, besides that very little of it 

 is dissolved, it occasions no descent of the liquor in the thermometer. 



Exper. 19. — Being mixed with blood lately drawn from the vein of a man, 

 but coagulated after settling, the blood was dissolved, and continued in that 

 state for the space of 24 hours. 



Exper. 20. — A solution of this salt being injected into the vein of a dog, first 



