l60 ACCOUNTS, ETC., OF THE BRITISH MUSEUM. 



Department of Mineralogy. 



Research. 



The systematic investigation and description of the 

 Mineral Collections have been in progress during the past 

 year. In the Sulphide and Sulpharsenite Division, a detailed 

 examination of the chemical and other characters has been 

 made for a large collection of tellu rides of gold, silver, and 

 mercury, presented by the Government, and by various gold- 

 mining companies, of Western Australia. The result of this 

 investigation has been to prove the non-existence of the 

 supposed species " Kalgoorlite " and " Coolgardite," and to 

 establish the chemical formula of Coloradoite. The crystallo- 

 graphic characters of Krennerite have been studied and 

 new forms observed. In the Halide Division a descriptive 

 catalogue has been prepared of the Hornsilvers, and that of 

 the numerous specimens of Fluor has been in progress. In 

 the Division of the Oxides, an investigation of the cut and 

 polished specimens of Zircon has been made with the view of 

 discovering a connection between the variations of specific 

 gravity and optical characters. In the class of Silicates 

 a chemical and optical examination has been made of 

 Serendibite, a new boro-silicate of calcium, magnesium, and 

 aluminium, from Ceylon. As regards the Hamlinite- 

 Beudantite-Jarosite group of minerals, the possibility of a 

 connection between the chemical composition and molecular 

 volumes has been under investigation. 



Of artificial products, a crystal lographic study has been 

 made of various carbides, and silicides of iron and manganese. 



A method for simplifying the use of the gnomonic pro- 

 jection in the study of crystals has been devised, and a table 

 for the transformation of spherical into plane co-ordinates 

 has been prepared ; in this connection also a protractor for 

 use in plotting poles and the determination of angles between 

 them has been designed. 



Crystallographic measurements have been incidentally 

 made on various other species, including Meneghinite, 

 Clinohumite, Cassiterite, Stilbite, Gypsum, Tellurium, 

 Tourmaline, Sphene, Apatite, and Baumhauerite. 



The petrographical examination of the rock-specimens 

 collected by the " Southern Cross " Antarctic Expedition 

 under Mr. C. E. Borchgrevink, has been continued, and a 

 descriptive report prepared. An investigation of the rock- 

 collections made by Professor J. W. Gregory and by Sii 

 Harry Johnston in British East Africa has been made, and a 

 description of the specimens, with illustrations, has been 

 prepared. For this petrographical work 172 thin sections of, 

 rocks have been microscopicall3'' examined, and the necessary 



