300 Col. Beaufoy's Astronomical Observations for Sept. [Oce. 



Article IX. 



Astronomical Observations, Sept. 1821. 

 By Col. Beaufoy, FRS. 



Basket/ Heath, near Stanmore. 



Latitude 51° 37' 44-3" North. Longitude West in time 1' 20-93". 



Sept. 11. Ingress of Jupiter's first sa- $ 10 1 ' 23' 29" ? Mean Time at Bushey. 



tellite i 10 24 50 $ Mean Time at Greenwich. 



Sept. 11. Emersion of Jupiter's thirds 10 30 12 ? Mean Time at Bushey. 



satellite { 10 31 33 ) Mean Time at Greenwich. 



Sept. 12. Immersion of Jupiter's second < 13 29 19 ) Mean Time at Bushey. 



satellite ( J 3 30 40 S Mean Time at Greenwich. 



Sept. IS. Emersion of Jupiter's third ( 14 30 09 ) Mean Time at Bushey. 



satellite , J 14 31 30 \ 3Iean Time at Greenwich 



) M 

 S 31 



Article X. 



Analysis of Tabular SpGrfrom Parvas. By P. A. V. BonsdorfF, 



Ph. D. of Abo* 



Among many rare minerals which occur in the lime quarries 

 of the parish of Pargas, there is a white radiated substance, 

 which was for a long time considered to be tremolite ; but an 

 analysis which I have performed shows that this mineral is tabu- 

 lar spar. It occurs principally in the lime quarry of Skr'abbdle, 

 in the parish abovementioned ; it is accompanied with granular 

 calcareous spar, blackish sphene, and an amorphous mineral of 

 a reddish colour, resembling idocrase, or garnet. 



The colour of this tabular spar is white, translucent at the 

 edges ; its lustre vitreous, but not very considerable ; it is 

 scarcely hard enough to scratch glass, and its fragments are fili- 

 form. By the blowpipe, at a high temperature, it melts at the 

 edges into a translucent shining glass ; with borax and microsmic 

 salt, it forms a clear glass ; with soda, the glass is opaque ; when 

 heated with solution of nitrate of cobalt, it assumes a blue 

 colour, proving that it does not contain magnesia, and, conse 

 quently, that it is not tremolite. 



I had great difficulty in procuring pure fragments of this 

 mineral for analysis ; because it is mixed with calcareous spar, 

 with very small grains, of a green substance, resembling actinote, 

 and of a white one, which seemed to be quartz. After these had 



* Extracted from Memoirs presented to the Academy of Sciences in Petershurgh. 



