452 Col. Beaufoy^s Astronomical Observations. [June, 



some of these, the front half of fig. 5 is the portion produced, 

 the plane / being then uppermost. In some of the segments, 

 however, there is a slight deviation from this exactness of posi- 

 tion of the planes^* or ft. 



Nitrate of Soda. 



The primary form is an obtuse rhomboid. 



PonP 106° 30' 



PonP 73 30 



and there are not any modifications on the crystals measured. 

 Some of these are lengthened into appa- 

 rently oblique rhombic prisms, as shown by Fig- 7 

 the produced dotted lines in fig. 7, but this ,.-•''> ■-... 

 disproportionate extension of some of the,.-''' \ \. ( 

 primary planes has been already stated not\"~-..^ .-V"' \ 

 to be unfrequent among crystals. \ v (' \ \ 

 I am, dear Sir, yours truly, 



H. J. Brooke. 



I have just learned that Mr. Levy has very 

 recently taken up this subject, and has mea- 

 sured and determined with a view to publica- 

 tion, the forms of many of the artificial crys- 

 tals, without being aware of my having previously occupied 

 myself in a similar manner. He has proceeded mathematically, 

 and will probably still give his results to the public ; and there 

 can be no doubt that he will confer an additional interest on the 



inquiry. 



Article X. 



Astronomical Observations, 1823. 

 By Col. Beaufoy, FRS. 



Bnshey Heath, near Stanmore. 



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



April 29. Emersion of Jupiter's first J 8h 19' 43" Mean Time at Bushey. 



satellite t 8 21 04 Mean Time at Greenwich. 



May 6. Emersion of Jupiter's' second J 8 26 32 Mean Time at Bushey. 



satellite < 8 27 53 Mean Time at Greenwich. 



