24 On the Nebula around Tlta Arrjus. 



List of Recorded Magnitudes of JEta Argus. — (Continued.) 



>* 



S 





o 



r^ 



S 



5 



1822 



2 





Fallows 





2.7 



by Abbott) 



1826 



2 





Brisbane 



1860 



3.0 



Tebbutt 



1827- 



1 





Burchell 





(made in 



same year 



1831 



2 





Taylor 





3.3 



by Powell, and 



1832 



2 





Taylor 





3.1 



by Abbott) 





(made 



in 



same year 



1861 



3.6 



Powell 





2 



bj 



' Johnson) 





(made in 



1 same year 



1833 



2 





Taylor 





4.2 



by Abbott) 



1834 



1.4 





Herschel 



1862 



4.9 



Tebbutt 



to 











(made in 



L same year 



1837 



1.4 





Herschel 





4.9 



by Abbott) 



1838 



0.5 





Herschel 



1863 



5.1 



Tebbutt 



1842 



1 





Maclear 





(made in 



same year 



1843 



0.5 





Maclear 





6.0 



by Abbott, and 



1845 



1 





Jacob 





5.0 



by Ellery) 



1850 



1 





Gillis 



1864 



5.2 



Tebbutt 



1854 



1 





Tebbutt 



1865 



5.2 



Tebbutt 





(made 



in 



same year 



1866 



5.8 



Tebbutt 





1.2 



bj 



• Powell) 



1867 



6.0 



Tebbutt 



1856 



1.5 





Powell 



1868 



6.0 



Tebbutt 





(made 



in 



same year 



1871 



7.0 



Eussell 





1.0 



by Abbott) 









Note added, 4th Octobee, 1871. 



On the 5tli of September, 1871, I examined this nebula with 

 the spectroscope ; owing to its unfavourable position, there was 

 not sufficient light to enable me to make any measures, and the 

 bright lines could only be seen when the observing room was 

 perfectly dark : I was therefore obliged to estimate the position 

 of the lines. When the telescope was directed to the bright portion 

 of the nebula preceding r^ and divided by the line 460" north of 

 it, a bright green line, estimated to be the nitrogen line usually 

 seen in nebula, and two fainter green lines on the violet side of it 

 were seen. On the 8th of September, I again saw these lines in 

 that part of the nebula, and in all the northern parts of the 

 nebula which were bright enough to give a spectrum, the same 

 bright green line was observed. I was unable to obtain any 

 spectrum of >] Argus itself. 



H. C. E. 



