14 



Sjögren, be placed in the most competent hands. Most of 

 the analyses , and among them those offering the greatest 

 difficulties, have been made in the laboratory of Professor 

 Sjögren by his chemical assistant, the eminent analyst Dr. 

 R. \lauzelius. For the valuable and liberal assistance thus 

 afforded I desire to express my hearty thanks to the these 

 gentlemen. Also to Baron De Geer, Professor of the Uni- 

 versity of Stockholm and Curator of the Mineralogicai Institution, 

 who has permitted me to perform the experimental part of my 

 own work at the Institution , my warmest acknowledgements 

 are due. 



As to the names of the special forms within the different 

 crystal classes, the nomenclature lately proposed by Groth ^) is 

 exclusively made use of in the present paper. For the designation 

 of the forms, Miller's indices are employed except as regards 

 the trigonal system, where the indices of four figures sug- 

 gested by Bravais have been used, as, of course, also for the 

 hexagonal system. The symbols of Naumann have been omit- 

 ted as quite unnecessary. As for the optical characters of the 

 minerals the views advanced by Fletcher-) have been adopted. 



P.Groth, Physikalische Krystallographie ; dritte Auflage 1895. 

 Mineralogicai Magazine Vol. IX p. 278. 



