178 Rev. W. V. Vernon's Analijsis of an alumitious Mineral 



Although the differing results of the experiments afford 

 little satisfactory explanation of the causes of the variations 

 in the curvature of the levels, and one or two might have been 

 differently anticipated, they amply serve to prove that the 

 mounting tends to render them less sensible, and point out the 

 necessity of verifying the accuracy of the scales furnished by 

 the artist. 



Leeds, Dec. 20, 1828. J, NiXON. 



XXVIL Analysis of an aluminous Mineral in the Collection of 

 the Yorkshire Philosophical Socicti/. By the Rev. William 

 V. Vernon, F.R.S. F.G.S. Pres. of the Yorkshire Philoso- 

 phical Society*. 



T^HE calcareous rock on the coast at Scarborough, which 

 -*■ Mr. Smith considers as corresponding with the great 

 oolite of Bath, is covered by beds of sandstone much marked 

 with oxide of iron. Whilst I was examining these beds in 

 1826, my attention was attracted by a mineralf, with which 

 they are in many parts veined, of a white colour, but not 

 bearing, to my eye, the appearance of calcareous spar. Finding 

 that this substance had the pi'operty of adhering strongly to 

 the tongue, I conceived it to be probably aluminous, and pre- 

 sented a specimen under that character to the Yorkshire Phi- 

 losophical Society, after having ascertained that sulphuric acid 

 and potash converted the greater part into alum. I have lately 

 examined it more accurately, and find it to differ from any of 

 the aluminous minerals which have been yet described. 



The mineral when pure is perfectly white, without lustre, 

 with a conchoidal fracture, easily scratched by the knife, and 

 polished by the nail ; it is highly adhesive to moist surfaces ; 

 when breathed upon, it has a strong earthy smell ; when put 

 into water, it does not become translucent nor fall to pieces, 

 but gains considerably in weight. The absolute specific gra- 



* Communicated by the Author. 



•j- In the account of these beds prepared by INlr. J. Phillips for his forth- 

 coming publication on the Geology of Yorkshire, the veins here mentioned 

 are thus described : " The calcareous and irony strata (great oolite. 

 Smith) have their long straight intersecting fissures often lined with double 

 laminae or septa of oxide of iron, between which sometimes occurs a white 

 compact, soft, smooth substance, which the Rev. W. Vernon has ascer- 

 tained to be a new aluminous mineral ; exactly similar septa, and occa- 

 sionally the same aluminous substance occur in the superincumbent vari- 

 able beds of sandstone ; and in addition, this bed presents a number of 

 ochraceous belts or zones parallel to the margins of the blocks, and beauti- 

 fully variegating the blue or white colour of the stone." 



vity 



