SOO Astronomical Ohservafions at Hackney Wick. [April, 



tion being mixed with muriate of barytes, gave 4G grains of 

 suiphate of barytes.* The reddish grey powder which separated 

 from the saline ley was treated in the same manner as the residue 

 of die English graphite. The constituents obtained by this 

 treatment from 200 grains of Spanish graphite were as follows : 



Black oxide of iron (derived from the pyrites) . . . 14*2 gr. 



Siiiia 3-0 



Alumina , 2*4 



Oxide of copper 1*0 



Oxide of titanium 3*1 



23-7 



Greenwich Time. 



8h 36' 13" 18'^' 

 7 52 54 18 



8 08 18 18 



12 25 42 18 



Article VIII. 

 Astronomical Ohservatmu at Hackney Wick, By Col. Beaufoy. 



Latitude Si-^ 32' 40" North. Longitude West in Time 6'82" 

 1813. 



Hackney Wick. 



Feb. 24, emeisson of Jupjter's 1st satellite.. 8h 36' 20'^ 



March 5, j-mersion ot ditto 2d ditto 7 53 01 



Marci* 6, inizneision of Coeti per moon. .. . 8 50 17 



March 6, emersion of ditto 9 43 17 



ftia cii 7, emersion of Jupiter's 3d satellite.. 8 08 25 



M.:iCK 8, iuaiiers'on o i Aldebaran,, not oh-} 



servp'1 , ) 



Marc*? 8, emersion of ditto 7 29 47 



11th Oitfo, Civil time (I, emersion of Ju-> 



piier's Isl sateili e 



Met eh 12, emerMon or ditto, 1st ditto 6 55 07 6 55 GO 18 



March 12, erne, sion of ditto, 2d ditto 10 30 06 10 29 £9 18 



These observations are set down in mean time, and were made 

 under favourable circumstances, with one of Doilond's five feet 

 refracting telescopes, with a magnifying power of about 80 

 times. 



Ihe moon's age being five days, and the non-illuminated 

 part of her disc extremely well defined, particular attention was 

 paid to ascertain if at the immersion of ( oeti the star had its 

 liglit ditnini^hed, but no such eflect took place. 



Uain, beivv een noon the 1st of February and the 1st March^ 

 2-200 inches. 



* 1 burnt 100 grains of compact pyrites from Katharine, in Raschau, with 

 an excess of saltpetre, and obtained from the residue 206*6 grains of sulphate 

 of barytes. 



22^1- of pyrites. 



