362 Col. Beaufoy's Astronomical Observations. [Nov. 



greater terminal edge of the prism, its height would be to its 

 greater terminal edge as 153 to 170 ; or, the three dimensions 

 would be nearly as 15, 16, and 17. 



1 That the prism is rectangular, and not square, cannot admit of 

 a doubt; but its height compared with its terminal edges may 

 require to be altered, in investigating the laws of decrement, by 

 which other secondary planes are produced.' 



P' on P or P" 90° 



P' on e or c' 90 



P on P" 90 



c one' 93 30' 



P'ondorrf' 147 30 



co P'on a 136 16 



co V'onb 136 48 



P' on c or c' 136 45 



P one 133 15 



William Phillips. 



Article V. 



Astronomical Observations, 1821. 

 By Col. Beaufoy, FRS. 



Bushey Heath, near Stanmore. 



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



Sept. 24. Immersion of Jupiter's first U5 1 ' 56' 55" ? Mean Time at Bushey. 



satellite }\5 58 16 » Mean Time at Greenwich. 



Oct. 7. Immersion of Jupiter's second < 1 39 16 ? Mean Time at Bushey. 



satellite ( 10 40 37 } Mean Time at Greenwich. 



Oct. 8. Occupation of A Aqua- <Immer. 5 31 00"6 } , T _,. . t. , 



rius by the moon. . . ?Emer. 6 27 51-8 J Mean Tlme at B^ey 

 Oct.* 13. Occupation of Atlas Pleiadum by the moon, Immersion 9 : ' 2' It"; 

 Emersion 9 h 59' 11"; Mean Time at Bushey. 

 Occultation of Pleione Pleiadum by the moon, Immersion 9 h 2' 56": 

 Emersion 9 h 49' 41"; Mean Time at Bushey. 



* Not having had a map of the Pleiades before me, I may have mistaken the names. 



