32 PROCEEDINGS OF THE WASHINGTOJs" MEETING 



passed his bo3^hood on a farm. In IS.SO lie married Annie H. Williams, 

 an artist. His wife died in 1893, but a son and daughter survive him. 



MEMOIR OF AUGUSTE MICHEL-LEVY 

 BY ALEXANDEB N. WINCHELL 



AugiTste Michel-Levy was born in Paris, August ?, 1844, where he died 

 in September, 1911, at the age of 67 years. His father was a physician, 

 who attained distinction as the director of the ^fedical School of Val-de- 

 Grace. At 20 years of age !Michel-Levy graduated from the Ecole Poly- 

 technique with first honors, and soon afterward entered the government 

 service in the Bureau of Mines (Corps des Mines, Ministere des Travaux 

 Publiques). His advancement in this work was rapid from grade to 

 grade : engineer, inspector, chief inspector, chief engineer, and finally, in 

 1887, director of the Geological Survey of France (directeur du service de 

 la carte geologicjue de la France). In 1880 he was in charge of the 

 laboratory of the natural history of inorganic substances at the College de 

 France. In 1885 he was selected as a member of a scientific expedition 

 sent to Andalusia by the French Academy of Science. 



The published writings of ^lichel-Levy show that his attention was 

 directed from the first to geological problems, and that his special interest 

 lay in the study of igneous rocks. His work in areal, stratigraphic, and 

 structural geology is indicated by the fact that he personally prepared ten 

 sheets of the geological map of France on the scale of 1 to 80,000. For 

 this purpose he studied the formations of Morvan, Beaujolais, Charolais, 

 Mont-Dore, Chablais, and some of the most difficult regions of Mont 

 Blanc, and published numerous explanatory memoirs concerning their 

 structure and history. The wide acquaintance with the geology of France 

 obtained through these and other studies and his keen insight into geo- 

 logical problems gave to him an authority, aside from that due to his 

 position, which his colleagues on the French Survey and geologists gener- 

 ally have come to recognize and accept in many difficult problems. 



But Michel-Levy is best known both in France and abroad for his 

 numerous important contributions to mineralogy and petrology. As a 

 mineralogist his writings deal with the zircons of granite, the various 

 forms of crystalline silica, the optical properties of the micas, the synthe- 

 sis of many rock-forming minerals, the precise measurement of optical 

 properties in thin sections, and especially the precise determination of the 

 plagioclase feldspars by means of microscopic study in polarized light. 

 It is probable that the remarkable advance in the science of petrology 

 resulting from the application of the polarizing microscope to the study 



