Mr Haidinger on Mesole. %l 



within a cavity in basalt, lined with small crystals of chabasie. 

 The disposition of small tabular crystals, of which the globules 

 consist, is here distinctly visible, resembling certain longish 

 globules of heavy spar, only in the latter the tabular crystals 

 are disposed parallel to the long diameter of the globular 

 shape, while in mesole they lie in an opposite direction. 



3. In the three specimens comprised under this number, 

 the crystals are not joined in their whole length, but show dis- 

 tinctly a four-sided tabular form belonging to the prismatic 

 system. Parallel to their broad face cleavage takes place with 

 great facility ; the laminae are slightly flexible, but, on account 

 of their minuteness, they easily yield to a slight pressure and 

 break. These crystals are joined on one end with their broad 

 faces in crest-like aggregations, which, if they were filled up 

 by a farther increase of the individuals, would produce glo- 

 bules as in the preceding variety. 



4. Reniform variety of a yellowish-grey colour on red de- 

 composed amygdaloid. The single globular masses consist of 

 larger individuals than those in No. I. so that the bright 

 cleavage may be easily discovered. The surface of the speci- 

 men is strewed with thin rectangular plates, which are crystals 

 of mesole. 



5. Individuals, resembling the last in size and colour, ag- 

 gregated in stalactitic shapes. All these, like the first, are 

 from Nalsoe. 



6. The individuals forming reniform groups are here simi- 

 lar to those of var. 4. but larger, about one-eighth of an inch 

 in diameter, of a pale yellowish-grey. The single cleavage 

 appears very bright. This variety was discovered by Sir 

 Charles Giesecke at Nia Kornak, in the island of Disco, Green- 

 land, where it occurs in the vesicular cavities of a basaltic 

 rock, associated chiefly with apophyllite and mesotype. In 

 another specimen in Mr Allan's cabinet there is likewise cha- 

 basie and levyne in very small crystals. I found the specific 

 gravity of this variety of mesole = 2.382. 



7. The size of the plates is here between a quarter of an 

 inch and half an inch. They have a bright pearly lustre oh 

 their cleavage planes, and the whole aggregate resembles in no 

 small degree the crystallized spermaceti. The colour of this 



