560 Dr. L. Leigh Fermor — What is Later ite ? 



d'hydrate d'alumine, melange d'oxide rouge de fer ", containing 

 52*0 per cent of A1 2 3 , 20*4 per cent of H 2 0, and 27'6 per cent of 

 Pe 2 3 , with a trace of Cr 2 3 . Berthier says that the iron is evidently 

 present in the mineral in the anhydrous condition and in " l'etat de 

 melange ", and that " le mineral pur " would be composed of 72 per 

 cent of Al 2 3 and 28 per cent of H 2 0, corresponding nearly to 

 Al 2 3 . 2 H 2 (>. He applies the terms mineral, ' ore,' and mineral, 

 ' mineral,' indiscriminately to his specimen, and as he proposes no 

 name for the substance it is difficult to say whether he regarded it as 

 a definite mineral, as the construction of a definite formula would 

 seem to indicate. 



A. Dufrenoy, on p. 347 of vol. ii of his Traite de Mineralogie (1845), 

 refers to the substance analysed by Berthier, and says " Elle ne peut 

 etre regardee comme une espece mineralc ". But in the index to 

 vol. iii of this work, published in 1847, the following entry occurs 

 (p. 799) : " Beauxite, nom donne a l'alumine hydratee de Beaux," 

 the reference being to vol. ii. 



St. Claire Deville ' in 1861 contributes a paper entitled " De la 

 Presence du Yanadium dans un Minerai Alumineux du Midi de la 

 France ". He heads his first chapter thus : " Minerals Alumineux ou 

 Bauxite," showing that he regarded bauxite (the correct spelling) as 

 an aluminous ore ; further, he mentions Berthier as the originator of 

 the name, as follows : " ce minerai particulier que M. Berthier 

 a appele la bauxite." On p. 321 Deville gives a number of analyses, 

 one of which shows 48*8 per cent of Fe 2 3 and only 332 per cent of 

 Al 2 3 , indicating an extension of the term bauxite to include very 

 ferruginous varieties. The amount of water present in these analyses 

 is generally insufficient for the formation of Al 2 3 . 2 H 2 0. The 

 presence of Ti 2 is shown. On p. 324 the term bauxite is applied 

 to an iron-ore from Paradou in Provence containing 60 per cent of 

 Fe 2 3 and 1 8 per cent of Al 2 3 and Ti 2 . 



Sufficient is quoted above to show that the name bauxite was not 

 given to a definite mineral, but to an impure aluminium-ore of very 

 variable composition, and that consequently its application has, really, 

 always been to a rock and not to a mineral. The assumption, perhaps 

 only intended as a suggestion, of the existence of the definite compound 

 Al 2 3 . 2 H 2 0, first made by Berthier, and adopted by Dana, is not 

 apparently justifiable, and it seems that bauxite must be regarded as 

 a true rock, and the term bauxite must consequently be available to 

 petrographers for use in this sense. The matter is summed up admirably 

 by Professor Lacroix on p. 342 of vol. iii of his Mineralogie de la 

 France et de ses Colonies (1901). Lacroix says that the examination of 

 a large number of analyses shows that bauxite, where it contains the 

 minimum of impurities, approaches nearer to the composition of 

 diaspore than of any other mineral, and that bauxite is to be regarded 

 as constituted of various colloid hydroxides of aluminium, mixed with 

 the corresponding hydroxides of iron, and with various impurities, 

 clay, quartz, sand, etc. " C'est en realite une veritable roche." ~ 



1 Ann. Chim. Phy., ser. Ill, lxi, pp. 309-42. 



2 Since the above was written we have received in the library of the Geological 

 Survey of India, vol. cxlviii of the Comptes Eendus (1909), in which there are 



