department of mineralogy. 159 



Department of Mineralogy. 



Research. 



The systematic crystallographic and chemical investiga- 

 tion of the Mineral Collections has been in progress during 

 the past year. In the Sulphide Division, the investigation 

 of the crystallographic and optical characters of some new 

 and rare minerals from the Binnenthal, Switzerland, has 

 been in progress ; the group of sulph-antimonites of lead 

 has been critically reviewed, and the specimens have been 

 re-arranged. In connection with the investigation of the 

 new mineral teallite, further chemical analyses have been 

 made of its allied minerals franckeite and cylindrite, and 

 the chemical relations of the three species have been dis- 

 cussed. In the Halide Division, a new copper mineral from 

 Sierra Gorda, Chili, closely allied to atacamite, has been 

 crystallographically and chemically examined. A detailed 

 crystallographic and optical examination has been made of 

 a suite of irregularly developed crystals of zircon from 

 Ceylon. 



Crystallographic measurements have been incidentally 

 made on various other species, including atacamite, augite, 

 babel-quartz, blende, chalybite, connellite, hydrocerussite, 

 malachite, mendipite^ rutile, schwarzembergite, stelznerite, 

 and tourmaline. 



Petrographical examinations have been made of specimens 

 of pillow-lava and other igneous rocks from Cornwall, and 

 of a collection of alkaline rocks from Dunedin, New Zealand. 

 The slip-catalogue of the collection of thin sections of rocks 

 has been brought up to date by the microscopic examination 

 of over 700 sections. 



The masses of meteoric iron from Great Namaqualand 

 and its neighbourhood have been under discussion, and 

 specimens have been polished, etched, and examined. 



In the chemical laboratory complete quantitative analyses 

 have been made of teallite, franckeite, cylindrite, and the 

 new copper mineral from Chili, and partial analyses have 

 been made of hussakite and '-'red rain" from the Azores. 

 Further, 42 doubtful minerals have been qualitatively 

 analysed. 



Publications. 



The new edition of the "Introduction to the Study of 

 Meteorites, with a list of the Meteorites represented in the 

 Collection," has been completed and passed through the 

 press. 



The following papers, relative to specimens in the collec- 

 tion, or to mineralogical theory and methods, have been 

 published in the " Mineralogical Magazine and Journal of 



