728 PETROLOGICAL ABSTRACTS AND REVIEWS 



WtJLFiNG, E. A. " Fortschritte auf dem Gebiete der Instrumenten- 

 kunde," Fortschritte der Min., Krist., u. Fetrog., Ill (1913), 

 pp. 63-92. 



A summary of the progress made, during the past decade, in 

 mineralogical and petrographical instruments, including goniometers, 

 microscopes, microscope accessories, conoscopes, total reflectometers, 

 photometers, chromoscopes, lighting-, projection-, grinding-, and 

 separating-apparatus, sclerometers, electromagnets, electric ovens, 

 drawing instruments, etc. A bibliography of 214 articles, and brief 

 descriptions of the various instruments are given. 



A. J. 



WuLFiNG, E. A. ''Eine einfache Vorrichtung fiir konstante Was- 

 serbader," Zeitschr. f. angew. Chemie, XXVI (1913), pp. 87-90. 



Describes a new water bath for constant temperatures. 



A.J. 



WuLFiNG, E. A. "Ueber die objektive Darstellung der Grenz- 

 kurven bei Kristallen," Sitzb. Akad. Wiss. Heidelberg, 191 2, 

 Ab. 19, pp. 14. 



WuLFiNG, E. A. ''Ueber Projektion mikroskopischer Objekte 



ins besondere im polarisierten Licht," Sitzb. Akad. Wiss. 



Heidelberg, 191 1, Ab. 36, pp. 40. 



Describes a lantern for projecting microscopic objects. With this 



instrument it is possible to project interference colors of minerals, 



interference figures, to show the optical character of minerals, and in fact 



to show upon the screen all of the phenomena seen with the polarizing 



microscope. 



A. J. 



WtiLFiNG, E. A. ''Ueber kristallographische Kaleidoskope," 

 Neues Jahrb., I (191 2), 37-50. 

 Describes an apparatus by means of which crystal form, crystal 

 symmetry, etc., may be clearly shown to students. 



A. J. 



