Mr. Aikin on Witherite found in Shropshire. \\\ 



texture being in large masses quite opake. The colour of the 

 witherite is white with the slightest possible, if any, tinge of yellow : 

 its fracture is broad striated approaching to strait-foliated : it is for 

 the most part; massive. I have seen only a single specimen that 

 presented any indications of a regular crystalline form. In other 

 particulars it agrees with the usual descriptions of this substance. 



The Anglesark witherite has been analysed by Klaproth, and 

 beside c carbonate of barytes appears to contain above two per cent, 

 of airbonate of strontites, and a scarcely appreciable quantity of 

 oxide of copper. The Stirian witherite, on examination by the 

 same chemist, appears to be a pure carbonate of barytes. The 

 presence of carbonate of strontites being a circumstance of some 

 interest, I was induced to examine the Shropshire Witherite for the 

 purpose of ascertaining whether in this particular it agreed with 

 that from Lancashire. 



For this purpose 200 grains were dissolved in muriatic acid, and 

 left behind 1 .8 gr. of a white powder which was sulphate of barytes. 



The muriatic solution being supersaturated with ammonia was 

 evaporated to dryness and ignited till the muriate of ammonia was 

 driven off: the residue was redissolved in water, but left behind 

 1.5 gr. of a brown sediment, which on digestion with sulphuric 

 acid was separated into 1. gr. of silex insoluble in the acid, 

 and 0.5 gr. of alumine coloured by oxide of iron, soluble in the 

 acid, and which deposited crystals of alum on the addition of 

 sulphate of potash. 



The purified muriatic solution was brought to the crystallizing 

 point, and the muriate of barytes which fell down was removed : 

 the mother-liquor was mixed with alcohol and heated, the fluid 

 (after standing a minute to clear) was poured off, and on cooling- 

 deposited long needled crystals of muriate of strontites. Water 



