2 1 I 2 1 2

Preliminary Note on the Spectrum of the Orion Nebula. By W. W. Campbell.

It has heretofore been assumed that the visible spec- trum of the Orion Nebula exhibits an essential and funda- mental sameness. This. view differs so radically from the results of my observations that I desire to present the following preliminary note on the subject.

The relative intensities of the three principal lines vary within wide limits for the different parts of the nebula. In the dense region adjacent to the Trapezium the in- tensities of the lines (wave lengths 501 , 496 and 486) are represented approximately by the ratios 4 : I : I . For many regions of medium intensity the lines at 501 and 486 are about equally bright. Many of the faint portions on the south and west borders of the nebula give a spectrum in which the third line (H@ 486) is brighter than the first (501). In particular, the isolated portion north-east of the Trapezium (surrounding the star Bond No. 734) gives a

spectrum in which the third line is at least five times as intense as the first.

The relative intensities of the first and third lines change rapidly as the slit is moved over the nebula. It often happens that of two adjacent parts in the short slit at the same time, one gives a spectrum in which the first line is stronger than the third, and the other a spectrum in which the third is stronger than the first.

The ratio of the intensities of the first and second lines remains practically constant at 4 : I . In nearly the whole nebula the second line is fainter than the third.

In general, the hydrogen line (486) is relatively very strong In the faint outlying regions. I t is relatively stronger in the Orion Nebula than in any other nebula I have examined, except the planetary nebula SD. - I 201 I 7 2 .*)

Mt. Hamilton, 1893 Oct. 18. w. W. CamQbeZZ.

*) This nebula wns discovered and the skong He line noticed by Mn. M. Fleming on the Harvard College plates. See A. N. 3049.

Mittheilungen iiber einen neuen veranderlichen Stern in Caseiopeja (1855.0 : ~3~ srnz7= c 5 8 " 53:8).

New variable Star in Caseiopeja. On the night

of the gth instant and again last night I estimated its magnitude as 8.3 . It does not appear in Dr. Chandler's list. Its approximate mean place for 1894.0 is

The star BD. +5802560, whose magnitude according to the BD. is 9.5, is apparently variable.

Rh. = ~3~ 7"'6f9 Decl. = +59"6:5.

Edinburgh, 2 1 East Claremont Street, 1893 Dec. 10. Thomas D. Anderson.

BD. +5802560, regarding which I wrote to you on the xoth instant, was last night only gmi. It was as nearly as possible equal to BD. +59?2663 (Helsingfors 13815) . This is a .very great decline from its magnitude on the 8th instant, when I could see it with my field-glass. I t was then of the same magnitude as BD. +58?2563 (Helsing- fors 1 3 8 5 1 ) ~ which I estimate as 8m3.

This rapid diminution in brightness would seem to indicate that this star has only been in a state of temporary activity and is not to be regarded as ordinarily variable.

Edinburgh, 2 1 East Claremont Street, 1893 Dec. 29. Thomas D. Anahson.

Zneatz.

~ + 5 8 ? 2 5 6 0 ist von Krueger am Cometensucher beobachtet :

Herr Prof. F. Kiishrer theilt aus den Originalen der BD. d. d. Bonn 1893 Dec. 18 folgendes uber den Stern mit:

Zone 1344, 1857 Aug. 30 Grosse 9.5 Luft gut. Zone 1352, 1851 Sept.16 9.5

ausserdem ist tiber diese Stelle gegangen die gleichfalls von Krueger beobachtete

Zone 1336, 1857 Aug. 26 hier fehlt der Stern, desgleichen aber auch der Nachbarstern +58?2559, der in den anderen beiden Zonen gleich wie jener als 9.5 beob. ist.6

K Y .