lxii proceedings of xhb geological sociExr. [March 1913, 



and petrographical papers, some fifty in number, appeared under 

 his name in French and German periodicals, principally in the 

 Bulletin of the French Mineralogical Society (of which society he 

 was a member), and in ' Tschermak's Mirier a logische & Petro- 

 graphische Mitteilungen.' Many of these papers were well illus- 

 trated by the author's own drawings, made under the microscope. 

 In 1894 a lengthy monograph on spheroidal (orbicular) structures 

 in holocrystalline rocks (granite, diorite, and gabbro) appeared 

 in the Memoirs of the St. Petersburg Academy. His last paper, 

 published in 1895, related to an improved form of the Babinet 

 compensator for determining the strength of double refraction of 

 mineral sections under the microscope. 



The minerals which he prepared artificially include quartz,. 

 tridymite, and cristobalite (the three crystalline forms of silica), 

 spinel, zircon, orthoclase, amphibole, diopside, biotite, analcite, and 

 diamond. His method consisted in heating a dialysed solution of 

 silica, together with various hydroxides, in a specially-constructed 

 steel bomb at high temperatures (250° to 550° C.) for several months. 

 Diamond was obtained in 1893 from a solution of carbon in molten 

 silver. 



Of other published work, mention may be made of his investi- 

 gation and detailed descriptions of the inclusions in rock-formiug 

 minerals, and more especially the secondary glass-inclusions found 

 in the minerals of certain rocks that had been caught up and acted 

 upon by igneous magmas. The spectroscopic analysis of minerals 

 and the chemical analysis of rare-earth minerals were also matters 

 that engaged his attention. Petrographical work consisted in the 

 description of material collected by him in America (including a 

 leucite-rock from Lower California, Mexico), Yolhynia, and Lake 

 Ladoga. [L. J. S.] 



By the sudden death of Ralph Stockman Tare on March 21st r 

 1912, at the untimely age of 48, the Society lost an esteemed 

 Foreign Correspondent, elected so recently as 1909, who had many 

 personal friends in this country and was held by them in deep 

 respect for his admirable qualities of character as well as for his 

 high scientific attainments. 



Born at Gloucester (Mass.), Tarr entered at Harvard University 

 in 1881, and, after enforced interruptions for practical service in 

 marine zoology and in geological field-work, he graduated in 1891. 

 In 1892 he was appointed Assistant Professor of Dynamic Geology 



