61 



glo\v. On tliese occasions the halo was extended and had a 

 tawny hue. 



There are others who haA'e observed the surrounding about 

 the sun. Bozuard says : — " On November 28 an attenuated 

 white vapour extended 30° or 40° from the sun." A number 

 of others observed a similar phenomenon, and from their 

 observations conclude that it was due to ice spiculsc. Mr. 

 Kershaw, in Knowledge, describes the halo as a kind of rosy 

 glow with its inner edge about 5° from the sun and outer 

 boundary from 20° to 25°, and says ice spicules would account 

 for its appearance within 20° to 30°, but its appearance within 

 this puzzles him. Mr. Talbot, of the Transvaal, has forwarded 

 news of appearances round the sun, and has also noticed that 

 the halo is most extended towards the horizon, and has noticed 

 several points in the changes of this halo similar to the changes 

 seen here. 



Although many have imputed the formation of this halo to- 

 the light refracted through ice crystals, I can find no record of 

 any one having made an extended scrutin}^ during the greater- 

 portion of the glow period. Now, my experience shows that 

 this halo or corona, whichever it may be called, is continually 

 changing ; that the space between its limb and the sun is con- 

 tinually changing ; that this space is rarely blue ; that it gene- 

 rally approaches to white. The space varies in extent from the 

 sun' from about 18° to 25° to 3° or 4°. The breadth of the 

 limb frequently amounts to quite 15°, and is often so as tO' 

 not to admit of measurement. But the halos round the 

 moon, when presumably due to ice, rarely exceed in the- 

 breadth of their limb 2° or 3°. The solar halo has existed right 

 on for a number of days, and the moon has been visible also 

 during that period. If the halo be due to ice, the halo should 

 also have been observable during night round the moon. My 

 notes show that it has only been observable to me once when 

 there has been a glow, and then it occurred late in the evening,, 

 whilst on the following morning there was scarcely any glow, 

 the colour of halo during the day not being red, clouds being 

 present more or less. 



On the other hand, the moon has (according to my notes)- 

 been visible when the glow was prominent, and has frequently 

 been enveloped in mist, as also some of the brighter stars and 

 planets, whilst on all occasions when a halo round the moon 

 has been visible it has evidently been due to matter that took 

 the form of clouds, though not always exactly the same. On 

 all these occasions (about 15) there was no glow. 



There is evidence to show that vapour tints are ]iot dependent 

 on a definite angle so precisely as ice tints are. In support of 

 this I quote authority. Herschel, in his meteorology, describes- 



