29S CF.I.ES'riNK AND 15 ARYTO -CF, LRSTIN F, OF CLIFTOX. 



The projiortioii of the two sulphates approach the formula — 

 .3 BaSO.,, 51 SrSOi, and the mineral is therefore evidently a 

 mixture. 



Searching for other specimens of celestine, I discovered a 

 large heap which had been dug out of foundations for houses, 

 immediately to the soutli of the east end of the tunnel, and only a 

 few yards from it. This heap amounted to at least a ton, and the 

 celestine was most beautifully crystallized, some of the crystals 

 when detached measuring two inches. This celestine varied in 

 colour from blue to reddish, and was perfectly different in appear- 

 ance from the baryto-celestine. The analyses of two portions 

 taken from different parts of this find gave the following numbers — 



Barium Sulphate ... 10.9 4.3 

 Strontium Sulphate ... 89. t 9/;. 8 



The first specimen of celestine which I obtained was reddish 

 in colour, the crystals opaque, and ill defined. They were 

 agglomerated together in much the same manner as the crystal 

 in a loaf of sugar. 



The above results induced me to ascertain whether this specimen 

 also contained barium, and the result of the quantitative analysis 

 shows that, although that element is present, it is only so in very 

 small proportions. 1 found — 



Barium Sulphate ... ... 1.2 



Strontium Sulphate .,. 98.8 



It would ai)pe:ir from what I have stated, coupled with 

 Mr. Stoddart's analysis of Clifton celestine, that that mineral 

 almost invariably occurs associated with sulphate of barium in this 

 neighbourhood, but that the relative proportions of the two 

 sulphates vary very considerably, even in specimens of the mineral 

 found within a few yards of each other, and indeed in certain cases 

 'n different portions of tlie same lump, as the two analyses recorded 



