Geology and Mineralogy. 397 



be supplied on application to Professor Charles Schucbert, Yale 

 University Musem, New Haven, Conn. chaeles schucheet. 



V. Interferenz-Erscheinungen im polarisirten Licht ; photo- 

 graphisch avfgenommen * von Dr. Hans Hauswaldt in Magde- 

 burg. Keue Folge, 1904. — The series of eighty beautiful plates 

 contained in this work forms a very valuable aid to the study of 

 the behavior of crystal sections in polarized light, in fact so excel- 

 lent are the photographic reproductions that, except for the 

 absence of color, the student can learn almost everything from 

 them that he could from the specimens themselves. This work 

 follows the " Interferenz-erscheinungen an doppeltbrechenden 

 Krystalle im convergenten polarisirten Licht " published two 

 years since by the same author, while still further plates are 

 promised in the future. The plan of the series now issued has 

 been made by Professor Liebisch of Gottingen, to whom the work 

 is dedicated ; Dr. Siedentopf, of the optical works of Carl Zeiss 

 in Jena, has also contributed materially to the success of the 

 enterprise in various directions. The execution of the plates (by 

 Studders and Kohl of Leipzig) leaves nothing to be desired. 



A complete statement of all that is given in this series would 

 require the reproduction in full of the table of contents. The 

 opening plates exhibit the axial figures for several species (calcite, 

 topaz, gypsum, albite) in converging polarized light as modified 

 by the aperture of the condenser (C 1 and C 2 with num. ap. = 0*636 

 and 1*168 in each case). Then follow a number of plates showing 

 the limiting curves of the complete interference figures in con- 

 verging light for calcite and quartz under varying conditions. 



The influence of the color of the light source is shown for cal- 

 cite, quartz, cerussite and titanite, wave-lengths of 620-720/*//, and 

 410-450/x/x respectively being used in each case. Other plates 

 show the dispersion of the optic axes of brookite for different 

 colors ; the effect produced by the combinations of mica plates of 

 Reusch and of Noerrenberg; the interference bands of wedges of 

 birefringent crystals in parallel polarized light ; the spectral analy- 

 sis of the interference colors of sections of birefringent crystals ; 

 the anomalous optical characters of beryl and the peculiar phenom- 

 ena yielded by boracite, leucite, perofskite, also garnet, milarite 

 and other species. Twin structure is exhibited for numerous 

 species ; also spherolitic structure ; further, the birefringent phe- 

 nomena called out in glass by rapid cooling and by pressure, and 

 the effect of change of temperature and pressure in the case of 

 crystals of various species. Finally, absorption phenomena are 

 fully illustrated. 



This summary will serve to show the great variety of phe- 

 nomena exhibited by the upwards of three hundred figures of 

 this unique work. 



8. Tableau systematique des Miner aux classes Wappres lenrs 

 proprietes chimiques et cristallographiques ; par P. Geoth. Tra- 

 duit de la quatrieme edition allemande par MM. E. Joukowsky et 

 F. A. Peaece. Avec corrections et additions de Pauteur. Preface 



