106 



common. The relation between the sizes of the single sur- 

 faces is generally as shown in the figure; the surfaces p, ш, 

 and g may sometimes be wanting. 



Fig. 4. Epididymite; Narsarsuk. 



Generally, the surfaces are not especially plane, but they 

 give, however, so good reflections, that they may be determine^' 

 with certainly. c{00l} is always striated parallelly to the a-axis 

 and, moreover, provided with irregular grooves and projections. 

 The crystals are always composed of two or more tables placed 

 upon each other, about parallel, and separated by deep furrows 

 in the edges of the crystals. This coalescing does not seem 

 to be owing to any twin-formation ; otherwise, however, nu- 

 merous twins are found, according to the law common in the 

 epididymite. 



The crystals are colourless and almost quite transparent; 

 the physical properties do not in any direction differ from 

 those common in the mineral. 



The crystals of epididymite project into cavities; most 

 frequently they are found on microcline, albite, and aegirite, 

 and are often accompanied by calcite and almost always by 

 astrophyllite sitting as a felt- like mass on the outside of and 

 among the crystals of epididymite, without ever penetrating 

 into them , so that it may very easily be quite loosened 

 from them. 



Catapleiite. 

 On the expeditions of the two years a very large material 

 of this mineral has been collected, so that now, I think, we 



