MINERALOGY. 231 



Babanek, Franz. Zur Charakteristik einiger auf den Pfibramer 



Erzgiingeii vorkommenden Mineralien. [Minerals from the Pribram 



Lodes.] Min. Mitt. Heft ii. pp. 75-88. 



Describes the occurrence of smoky quartz, barytes, calcite, cerussite, 



wulfenite, pyrrhosiderite, lillite, antimony, antimonito, pyrostibnite, 



allemontite, steinmanite, boulangerite, jamesonite, heteromorphite, 



bournonite, polybasite, and diaphorite. F. W. R. 



Baltzer, Dr. B. [Occurrence of Tridj-mite.] Vierteljahrsschnft nat. 



Ges. Zurich, 20 Jahrg. pp. 182-184 ; Neue ZiiricJier Zeit. Jan. 13, 



1875, Xo. 21 ; N. Jahrh. Heft iii. pp. 316, 317. 



Gives a history of the discovery of tridymite ; describes the eruption 



of Vulcano, on Sept. 7, 1873 ; calls attention to the new type of 



volcanic ash that was then ejected during 3 hours, and shows, from 



chemical analysis, spec, grav., and optical characters, that these ashes 



consisted of tridymite. Suggests that the tridymite was formed by the 



action of acid vapours on the rocks forming the walls of the crater ; 



that this decomposition had been going on since the previous eruption, 



^ 87 years before ; and that the tridymite which had thus been formed 



was ejected on the first violent explosion of gases, which was succeeded 



by the eruption of ordinary ashes. F. W. 11. 



Barcena, Mariano. Estudio Quimico del Livingstonite. [Chemical 

 Study of Livingstonite.] Naturaleza, t. iii. no. 9, pp. 172-175. 



A recent analysis of Livinr/stonite gave : — sulphur, 29*08 ; antimony, 

 53-12 ; mercury, 14 ; and irofi, 3*5 per cent. From this analysis the 

 following formula may be deduced : — 4Sb"S^ + HgS + FeS^. The mineral 

 occurs at Huitzuco in the State of Guerrero ; where it is associated 

 with carbonate and sulphate of lime, native sulphur, cinnabar, valen- 

 tinite, and antimonite. F. W. R. 



. Notas sobre las Esferolitas de Mexico. [Spheerolites of 



Mexico.] Nataraleza, t. iii. no. 10, pp. 190-194. 



These esferolitas are concretionary bodies of globular and other forms, 

 consisting apparently of a mixture of orthoclase-felspar with free 

 silica. An analysis of one gave: — silica, 79*12; alumina, 12; potash 

 and soda, 3*58 ; oxide of iron, 2*45; magnesia, 1*1 ; loss, 1*75. The 

 concretions are found free in the superficial deposits near volcanic 

 mountains, chiefly those of trachytic porphyries ; others occur em- 

 bedded in iwq)hyry or obsidian, and are frequently found in cavities in 

 the latter rock. F. W. R. 



Barstow, Dr. W. Sulphurets : What they are. How Concentrated, 

 How Assayed, and How Worked ; with a chapter on the Blowpipe 

 Assay of Minerals. Pp. 120. 12mo. San Francisco 4' London. 



Bauer, M. [Optics and Mineralogy.] Zeitsch. deutsch. geol. Oes, 



m. xxvii. Heft 4, pp. 949-955. 

 Contribution to a discussion with M. Des Cloiseaux as to the con- 

 stancy of certain optical properties of minerals. 



