SELF-LUMINOUS NIGHT HAZE. 



By E. E. BARNARD. 

 (Read April 25, 1919.) 



In the Proceedings of the American PhilosopJiical Societv, Vol. 

 50 (1911), p. 246, a paper was contributed by the present writer on 

 the subject of "Self-Luminous Night Haze," where observations 

 were given of a kind of luminous, streaky haze seen at night in 1910 

 and 191 1 which seemed to have no connection with the ordinary 

 aurora. Apparently this is a little-known phenomenon. It is well 

 worthy, however, of record and study. The only reference to it 

 that I have found, and it was not known to me at the time of my 

 previous paper, is an account of what was probably the same phe- 

 nomenon by T. W. Backhouse, who gives occasional records of it 

 in a long paper on the aurora, under the name of " irregular au- 

 roras," as far back as December 13, 1862. I will quote his entire 

 reference to the phenomena as given in No. II, p. 109, Publications 

 of West Hendon House Observatory, Sunderland, England. " * irr.' 

 means a night when the aurora was only an irregular one, not per- 

 ceptibly of a magnetic character; I do not know whether these are 

 true auroras or not. They consist of bands and patches of light, 

 the positions and direction of which have no particular relation to 

 either the magnetic decHnation or dip; they appear to lie in a hori- 

 zontal stratum, but differ from clouds in being self-luminous and 

 transparent, and also not exactly like any kind of cloud in appear- 

 ance, and I should think they are at a greater height. They do not 

 appear specially in the north. As auroras of this class are always 

 faint, their spectrum proves little ; but I have never made out that 

 it was more than a continuous one. An examination of this table, 

 however, shows that these irregular auroras are more frequent about 

 the time of the maximum of sun-spots than at the minimum, which 

 goes towards proving that they are of the same magnetic nature as 

 the ordinary auroras." Air. Backhouse did not seem to notice that 



223 



