82 Prof. Brongniart on Websterite found 



the erroneous appellation of native ahtmina; afterwards by that 

 of aluminite (already appropriated to aluminous schist), and 

 which I have in another place* named Websterite, dedicating 

 it to Mr. Webster of London f , who first discovered this sub- 

 stance at Newhaven, near Brighton. 



The history of this mineral, independently of the geological 

 circumstances connected with it, is very remarkable f. It was 

 at first, and for a long time, taken for pure alumina ; though, as 

 it was difficult to imagine how such a substance could exist in 

 a state of perfect purity in the midst of very recent beds, its 

 origin was rather attributed to some of the processes of a ma- 

 nufacture which formerly existed in the spot where it was 

 found. In fact, its aspect, and its form (that of nodules about 

 the size of nuts), its position so near the surface of the earth, 

 and its being the only example which had till then occurred 

 of this substance; lastly, the complete ignorance in which we 

 were of the date of the stratum in which it had been met with, — 

 all contributed to excite the idea that it was merely a product 

 of art accidentally buried in the loose soil. 



Afterwards its properties were more carefully examined: 

 first Mr. Schreiber observed its crystalline structure, which is 

 not visible but by the microscope § ; then MM. Simon, of Ber- 

 lin, and Bucholz detected the presence of sulphuric acid. 

 M. Chenevix supposed that it was a sulphate of alumina hav- 

 ing the base in excess ; and finally, M. Stromeyer proved that 

 it was a subsulphate of alumina in definite proportions, con- 

 taining 47 per cent of water, or a combination of one atom of 

 alumina, one atom of sulphuric acid, and 9 atoms of water. 

 AZ.S4- 9Aq. 



Mr. Webster having discovered a similar mineral at New- 

 haven ||, M. Stromeyer determined its composition to be the same 

 as that found at Halle : afterwards M. de Basterot meeting with 



a white 



* See the Supplement to Vol. iii. of the Dictionnaire des Sciences Na- 

 turelle, article Argile Native. 



f Late Secretary and Curator of the Museum of the Geological Society 

 of London, and now Professional Geologist and Lecturer on Geology. 



% This history was given much in detail by Keferstein (Leonh. tasch., 

 10th year 1816, p. 33) j and M. Bonnard has inserted an abridgement of it 

 in the Annates des Mines, 1821, torn. vi. p. 588. 



§ I have verified this observation, and have described it in my Traite 

 elementaire de Mineratogie, published in 1807, t. i. p. 515; M. Keferstein 

 repeated it, and rendered the results more interesting by comparing them 

 with the microscopic appearance of other earthy substances. 



|| In the enumeration of facts respecting the history of this mineral sub- 

 stance, it may be proper to observe, that it was in 1812 that Mr. Webster 

 found it at Newhaven : shortly afterwards it was determined by Dr. Wol- 

 Iaston and Mr. Tennant to be a subsulphate of alumina ; and the latter 



gentleman 



