544 Chronicles of Science. [Oct., 



praktische Chemie' some "Communications on Bichmondite, Os- 

 melite, and Neolite,"* and also " On Pyrophyllite, Hydrargyllite, 

 Pennine, Chlorite, and Clinochlore."t These papers are chiefly 

 occupied by a collation of numerous analyses of the above-named 

 minerals, and by attempts to deduce rational formulae therefrom. 



A careful study of the minerals known as pholerite, nacrite, 

 stein-mark, and kaolin, has led Messrs. Johnson and Blake to the 

 conclusion that these minerals are sufficiently related to justify their 

 consolidation into a single species, for which they suggest [the name 

 of Kaolinite,\ since the substance is represented in its purest form 

 by the basis of certain kaolins or china-clays. Kaolinite crystal- 

 lizes in the rhombic system, and has a composition agreeing with 

 that deduced by the late Prof. Forchhammer from his analyses 

 of porcelain-clay, viz. — 



3 Al 2 3 , + Si 3 + 6 HO. 



The brilliancy and variety of the tints presented by fluor spar 

 have attracted the attention of M. Wybrouff, who has made them 

 the subject of an elaborate series of investigations, partly chemical, 

 and partly microscopical. These researches show that the fluor 

 spars hitherto examined owe their colours to the presence of certain 

 hydrocarbons, which in many cases have arisen from the decompo- 

 sition of bituminous limestones. The author has given particular 

 attention to a fetid fluor (Stinkfluss) from Wolsendorf in Bavaria, 

 termed Antozonite in accordance with the supposition that it con- 

 tains the so-called antozone. It may not be unnecessary to remark 

 that Schonbein regards oxygen in its ordinary inactive condition as 

 a compound of ozone, or negative active oxygen (0), with antozone 

 or positive active oxygen (o) ; the latter condition of the element 

 is supposed to exist in the "Wolsendorf fluor spar. Wybrouff, how- 

 ever, shows that the odour which this variety emits on friction 

 proceeds, not from the presence of free antozone, but from the de- 

 composition of the organic colouring matter. The connection 

 between the colour and the odour is indeed clearly brought out by 

 his microscopical observations, for which the reader must refer to 

 the original paper. § 



Herr Pauhnyi, of the Mining School of Schemnitz, has com- 

 municated to the Academy of Sciences at Pesth, an account of a 

 new mineral which he has recently detected in a brecciated specimen 

 from a vein at Kremnitz, in Hungary. It occurs in cubic crystals 

 of a black colour and a vitreous lustre, giving an uneven fracture 



* ' Journ. f. Prakt. Chem.' 1867, No. 9, p. 6. 



t Ibid., p. 17. 



% " On Kaolinite and Pholerite :" * Silliman's American Journal of Science and 

 the Arts,' May, 1867, p. 351. 



§ Eecherches microscopiques sur les substances colorantes des fluorine. Bul- 

 letin de la Soc. Imp. des Naturalistes de Moscou. Tome xxxix. p. 150. 



