ORDER VI. PRISMATIC KOUPHONE-SPAE. 237 



surface drusy, composition columnar. Massive : 

 composition columnar, consisting of delicate, straight, 

 and generally divergent individuals, radiating from 

 a centre ; sometimes aggregated into angulo-granu- 

 lar masses. Spheroidal shapes formed in vesicular 

 cavities. 



OBSERVATIONS. 



1. Mr PHILLIPS has given the first good representation 

 of a crystal belonging to the present species, greatly re- 

 sembling that of Fig. 174. The inclination of 6 on & has 

 been found = 146 16', e on M = 117 14', while that of o 

 on M is = 116 40'. The only variety to which the pre- 

 ceding description and the characters of the Characteristic 

 refer, is that from Auvergne. However similar in various 

 respects it may be to other varieties, as to those from Ice- 

 land, Scotland, the Tyrol, Faroe, and other localities ; yet 

 it cannot be united with them within one and the same 

 species, on account of the difference of several of their 

 properties. The real difference between several of them 

 have been sufficiently demonstrated by the labours of Pro- 

 fessor FUCHS, Dr BREWSTER, Mr BROOKE, Mr PHIL- 

 LIPS, &c. ; and no doubt an accurate investigation of all 

 the physical properties of these substances will enrich 

 the remarkable genus of Kouphone-spar, with several new 

 species. From this investigation it will also appear which 

 of the various kinds of Mesotype must be united with 

 the present species. 



* The angle of the prism M is given in the variety from 

 Auvergne 9 1 20' 9 1 1 0'. 



Hogau (Xatrolite) 91 35' 91 W. 



Iceland (Mesolite) 91 22' PHILLIPS. 91 20'. BROOXE. 

 From various observations I have found the first of these 

 from 90 59' to 91 3', the third from 91 23' to 91 27'; 

 moreover, a variety from Faroe =91 28' 91 29', and 

 one from the district of Maloa in East India = 91 23'. 



