1835.] Analysis of Wollastonite . 221 



into a white enamel with froathing. With borax it fuses 

 into a bead, yellow while hot, but becoming colourless on 

 cooling. With salt of phosphorus in excess, it fuses into a 

 colourless bead, leaving a skeleton of silica. With carbo- 

 nate of soda, it effervesces and fuses into an opaque bead 

 with a reddish blue colour. 



25 gr. were twice analyzed, by fusion with carbonate of 

 soda and solution in muriatic acid precipitation by the appro- 

 priate re-agents. The sum of the constitutents in one case, 

 (consisting in both of silica, lime, magnesia, peroxide of 

 iron, alumina and water,) w r as 22*050 gr., and in a second 

 instance, 22*455 gr. It was obvious, therefore, that the 

 deficiency was owing to the existence of an alkali as a con- 

 stituent of the mineral. 



10 gr. of the mineral were finely pounded, and intimately 

 mixed in a platinum crucible with 50 gr. carbonate of 

 barytes, prepared by precipitating the chloride of barium 

 by carbonate of ammonia, the chloride of barium having 

 previously had a stream of sulphuretted hydrogen passed 

 through its solution, to separate the lead which is usually 

 mixed with that salt as it. is met with in shops. 



The mixture was kept at a red heat for nearly two hours. 

 The decomposed mass was then digested in dilute muriatic 

 acid. The whole of it dissolved with the exception of the 

 silica which was thrown on a filter and washed with hot 

 water. Carbonate of ammonia, and a little caustic ammonia 

 precipitated the remaining constituents and the barytes. 

 The liquid from which every thing was separated except 

 the alkali was evaporated to dryness, and cautiously ignited 

 in a platinum capsule. What remained proved to be chlo- 

 ride of sodium. It weighed 1*8 = *72 sodium, which is 

 equivalent to *96 soda. The constituents per cent, are, 



99*420 



