depaktxment of mineralogy. 1g3 



Department of Mineralogy. 



Research. 



A large collection of South American minerals, brought 

 together by the late Mr. Theodor Hohmann of Chili, has been 

 under investigation in the course of the year 1903. Amongst 

 these specimens was discovered a new sulphostannite of lead 

 (Teallite) : crystals of it have accordingly been measured and 

 the chemical formula of the compound has been determined. 

 From the same collection crystals of andorite, atacamite, 

 brochantite, caracolite, hemimorphite, paralaurionite, scoro- 

 dite, stelznerite, and tetrahedrite have been measured. 



Various Bolivian minerals and rocks, presented by Mr. M. 

 Roberts, have been examined, and in this connection crystals 

 of augelite, barytes, calcite, cerussite, and vivianite have been 

 measured. 



A new mineral, bakerite, has been submitted to a critical 

 examination. 



Crystallographic measurements have been incidentally 

 made on various other species, including adamite, anglesite, 

 apatite, axinite, cinnabar, copper-pyrites, enargite, fluor, 

 gypsum, hornblende, idocrase, manganite, pucherite, rhodo- 

 chrosite, rutile, sphene, tourmaline, and wollastonite. 



By means of the new inverted goniometer numerous obser- 

 vations have been made relative to the refraction of light by 

 crystals of axinite, calcite, and by artificially-faceted zircon. 



Petrographical examinations have been made of rock 

 collections from Argentina, Cornwall, and Aden. In the 

 course of these examinations, and in the preparation of a slip 

 catalogue of the collection of thin sections of rocks, 2,763 

 sections have been microscopically examined. 



In the chemical laboratory quantitative analyses have 

 been made of the new sulphostannite of lead and also of 

 franckeite, an allied mineral, from Bolivia. Further, 25 

 doubtful minerals have been qualitatively analysed. 



Puhlications. 



A new edition of the " Introduction to the Study of 

 Meteorites, with a list of the Meteorites represented in the 

 collection," has been in preparation, and is nearly ready for 

 the printer. 



New editions of the " Introduction to the Study of 

 Minerals with a Guide to the Mineral Gallery," "The 

 Student's Index," and the penny " Guide " have been prepared 

 and seen through the press. 



Further, the following papers relative to specimens in the 

 collection, or to mineralogical theory and methods suggested 

 by the examination of the specimens, have been publishedin 



127. M 



