IQO PETROLOGICAL ABSTRACTS AND REVIEWS 



material is in part amorphous, in part of fine crystal particles. Secon- 

 dary minerals are calcite, zeolites, biotite, chlorite, and glauconite. The 

 presence of glauconite, foraminifera, radiolarians, and sponge spicules, 

 and the gradual transition of the tuff to other sedimentary rocks, indicate 

 a submarine origin. A. J. 



BoEKE, H. E. "Raumliche ternare KristalKsationsmodelle fiir 

 den Unterricht in physikalisch-chemischer Mineralogie," 



Centralhl. f. Mm., etc., 1912, 257-69. 



BoEKE, H. E. " Karbonschmelzen unter Kohlensauredruck. 11. 

 Ueber Witherit, Alstonit, Barytokalzit und Strontianit," 

 Mitth. d. Naturforsch. Gesell. Halle, III (1913). Pp. 12. 



BoEKE, H. E. "Mineral- und Gesteinsbildung aus dam Schmelz- 

 fluss (Magma) und durch Pneumatolyse," Handworterbuch der 

 Naturwissenschaften, VI (1912), 919-30. 

 A general paper on the formation of minerals and rocks from a 



magma. 



BoEKE, H. E. "Die Schmelzerscheinungen und die umkehrbare 

 Umwandlung des Calciumcarbonats," Neues Jahrb., 191 2 

 (I), 91-121. 



An apparatus is described for producing temperatures up to 1600° and 

 under pressures to 150 atmospheres. Iceland spar was found to melt, 

 without decomposition, under a pressure of at least no atmospheres of 

 CO2, at 1289°. Mixed melts of calcium carbonate and calcium oxide 

 were found to crystallize as a eutectic of 91 parts by weight of CaCOs 

 and 9 parts of CaO at 1218°, and without the formation of crystals of 

 intermediate composition. At 970=^=5° calcium carbonate reaches its 

 inversion point; below this calcite is the stable form. A. J. 



BoEKE, H. E. "Ueber die graphische Ermittelung der Krystall- 

 elemente und den Zonenverband in der gnomonischen Pro- 

 jection," Zeitschr.f. Kryst., LII (1913), 175-78. 



BowEN, N. L. "The Melting Phenomena of the Plagioclase 

 Feldspars," Amer. Jour. Sci., XXXV (1913), 577-99. 



