from Mount Vesuvius* 261 



If 24,1 grains of this precipitate correspond to 10 grains of 

 sulphate of potash, 17,2 grains of it correspond to 7,14 grains 

 of this salt. 



It has been seen (w) that 10 grains of the saline part of this 

 volcanic salt would have afforded 12,55 grains of sulphate of 

 barytes. 



But 7,14 grains of sulphate of potash form only 9,42 grains 

 of sulphate of barytes,* and therefore the remaining 3,13 

 grains of sulphate of barytes would be produced by the sul- 

 phate of soda, and correspond to 1 ,86 grains of it in an arid 

 state, or uncombined with ice.*f 



10 grains of the saline part of this native salt would have 

 produced 1,12 grains of ignited muriate of silver {k). By ac- 

 curate experiments 241 grains of ignited muriate of silver 

 have been found to correspond to 100 grains of ignited muriate 

 of soda. J 



Consequently the soluble portion of the present Vesuvian 

 salt consists of 



Sulphate of potash - - 7,14 



Sulphate of soda - - ifiS 



Muriate of soda - - 0,46 



Muriate of ammonia > 

 Muriate of copper [ - - 0,54 



Muriate of iron J 



10,00 

 t. The insoluble sandy residue (^) having been thoroughly 



• Dr. Marcbt on Dropsical Fluids. 



+ Prof. Klaproth's Essays, Vol. I. p. 282. 



X Dr. Hbnrt, Phil. Trans. 1810. 



M m 2 



