168 ACCOUNTS, ETC., OF THE BRITISH MUSEUM. 



Department of Mineralogy. 

 Research. 



During the past year the physical and chemical investigation^ 

 of specimens belonging to various species has been continued. 

 In the Silicate Division a crystallographic examination has been, 

 made of crystals of phenakite recently discovered in Brazil, 

 and two new forms have been noted. In the Phosphate 

 and Arsenate Division, a green arsenate from the Indian^ 

 manganese deposits has been investigated, and the chemical 

 composition and crystalline symmetry have been determined ; 

 a more exact determination of the crystallographic constants 

 of the recently discovered mineral tarbuttite has been made^ 

 by the measurement of new crystals, and the refractive indices- 

 have also been determined ; crystals of a new phosphate from 

 the phosphate-rocks of South Australia have been examined ; 

 and new occurrences of lazulite from Bolivia, and of xenotime 

 from Western Australia have been investigated. 



Specimens of minerals recently collected at the New 

 Brancepeth Colliery, near Durham, have been examined. In 

 this connexion crystals of witherite, the rare mineral alstonite,^ 

 and uUmannite (a sulph-antimonide of nickel, new to the- 

 British Isles) have been measured, optic sections have beenj 

 cut and examined, and chemical analyses have been made. 



Crystallographic and optical measurements have been inci- 

 dentally made on various other species, including atacamite,. 

 calcite; chabazite, corundum, diopside, ilmenite, mimetite,. 

 orthite, topaz, and whewellite. 



The microscopic examination of dolerites and rhyolites. 

 from Natal and Zululand has been completed, and a description 

 has been prepared for publication. 



A basalt from Co. Limerick has been microscopically andl 

 chemically examined. 



A new meteoric stone from Simondium, Cape Colony, has^ 

 been examined and described. 



A camera lucida attachment for drawing " light-figures " and 

 small crystals on the goniometer has been devised. 



In the chemical laboratory, quantitative analyses have beeni 

 made of the green arsenate from India, basalt from Co. Limerick,, 

 and olivine from the Simondium meteorite, and partial analyses 

 have been made of alstonite and ullmannite ; many doubtful 

 minerals have been qualitatively analysed. 



Publications. 



A new and enlarged edition of the Introduction to the 

 Study of Rocks has been prepared and published. 



