244 MINERALOGY. 



Herold, Hugo. TJeber die Kaoline der Formation des mittleren 



Buntsandsteins in Thiiringen. [The Kaolins of the Middle Bunter 



Sandstone of Thuringia.] Pp. 44. 8to. Jena. 



Kaolin occurs largely as a cementing medium in these sandstones. 



It is seen under the microscope to be a mechanical mixture containing 



small flakes, resembling mica, and minute fragments apparent!}^ of 



quartz. There are also the forms which have been described as microver- 



miculite and microschorlite. Analyses of the purified kaolin lead the 



author to suggest several closely related formulae : — 



1. AlA . SSiO^ + ^HO. 2. AI.P3 . 2SiO, + HO. 

 3. 2A1,03 . 4SiO, + 3H0. 4. k\0^ . 3SiO, + 2H0. 

 These formulae show that the kaolin of the sandstone has a similar 

 composition to that of the kaolin derived from granite ; but the former 

 is believed to owe its origin to the decomposition of mica and not of 

 felspar. F. W. K. 



Herouard, — . Analyse de Minerais de Cuivre recueillis a Belle- 

 Isle-en-Mer. [Analysis of Copper-ores from Belle-Isle-en-Mer 

 (Brittany).] BuU. Soc. Linn. Norm. ser. 2, t. viii. pp. 158-160. 



Hessenherg, Fr. von. Mineralogische iS'otizen. [Mineralogical No- 

 tices.] Neue Folge, Heft ix. Pp. 26, 3 plates. 4to. FmnJcfurt- 

 a.-M, 



Higgs, Samuel, Jun. Notice of an accumulation of carburetted 

 hydrogen or ** Firedamp " in the Ding-Dong Mine, situated in 

 the parish of Madron, near Penzance. Trans. R. Geol. Soc. 

 Cornwall, vol. ix. pt. 1, pp. 34-37. 

 In reopening part of the mine which had been under water, fire- 

 damp was met with in one of the old levels, and caused several 

 explosions. It is supposed that it was generated by decaying timber. 



C. L. N. F. 



Hintze, Dr. [VesuvianMica.] Pogg. Ann. Bd. civ. pp. 66, 67. 



Kesults of investigation of the optical and thermal characters of the 



red mica of Vesuvius, published as an appendix to Prof, vom Hath's 



*Min. Mitt.' [p. 254]. The author's investigation shows that the 



mica is monoclinic. F. W. R. 



Hirschwald, Dr. J. Zur Kritik des Leucitsystems. [Crystallization 

 of Leucite.] Min. Mitt. Heft iv. pp. 227-250, with plate. 



A critical examination of the crystalline forms of Leucite. Argues 

 against Prof, vom Bath's views on the quadratic crystallization of this 

 species, and maintains that leucite is regular, but supports Scacchi's 

 view of its polysymmetry. F. W. R. 



Hornstein, Ferd. Fried. Kleines Lehrbuch der Mineralogie ; unter 

 Zugrundlegung der neuen Ansichten in der Chemie fiir den 

 Gebrauch an hoheren Schulen bearbeitet. Zweite vermehrte und 

 verbesserte Auflage. [Elementary Treatise on Mineralogy, accor- 

 ding to Modern Chemistry ; for use in Higher Schools.] Pp. 320 ; 

 5 plates, 48 figs, in text. Cassel. 



