248 BARNARD— SELF-LUMINOUS NIGHT HAZE. [April 21, 



they may be quite broad, they have strongly suggested the " dawn " 

 or glow that precedes a bright moonrise. Their luminosity is uni- 

 formly steady. 



The reason I speak of this matter as haze, and the reason I think 

 it is only ordinary haze made self-luminous, is because on one occa- 

 sion I watched a mass of it in the northwestern sky which was slowly 

 drifting northerly in the region of the great "dipper" of Ursa 

 Major as daylight came on. These hazy luminous strips had been 

 visible all the latter part of the night — new strips coming and going 

 slowly, sometimes several being seen at once. As daylight killed 

 them out I noticed, when the light had increased sufficiently, that 

 there were strips of ordinary haze exactly the same in form and 

 motion and occupying the same region of the sky. I am sure they 

 were the same masses that had appeared luminous on the night sky. 

 Alt impression, therefore, is that these hazy luminous strips were 

 only the ordinary haze which had for some reason become self- 

 luminous. I am specially certain that these masses are not luminous 

 as a result of any great altitude which might bring them within reach 

 of the sun's light, for they were frequently seen in such positions 

 that the sun's rays could never reach them. The sun or moon, there- 

 fore, had nothing to do with their illumination. It is also needless 

 to say that they are not related to the pulsating auroral clouds which 

 I have previousl}- mentioned. 



I have not noticed this luminous haze in former years, though it 

 may have been present, and did it not seem unreasonable, one might 

 suspect some relation between this condition of the atmosphere and 

 the possible passage of the earth through a portion of the tail of 

 Halley's comet on 1910, May 19. 



I will give here the observations which I have obtained of these 

 singular features. It seems to me that these objects should be ob- 

 served and a record made of the times of their visibility and their 

 motion, etc. It would be valuable to have records of them from 

 different stations to see if their luminosity is due to some general 

 condition of the earth's atmosphere at the time. It is not probable 

 that this luminosity is in any way due to local conditions. In the 

 records here given, it is possible that on one or two occasions an 



