of Edinburgh, Session 1877 - 78 . 
545 
This suggestion seems fully to explain all the appearances which I 
saw. It will he observed that both Sir R. Christison and Mr Buchan 
noticed the peculiar brightness of the clouds near the sun, so that it 
is probable that this explanation applies to the phenomenon as seen 
by them also. The peculiarities noticed in the position of the spuri- 
ous bows (when seen) are of course dependent on the actual size, as 
well as the greater or less uniformity of size, of the drops which pro- 
duced the rainbow ; and these may well have been exceedingly vari- 
able as regards both time, locality, and height in the atmosphere. 
[Added, April 8.] 
I find that this nearly colourless rainbow is very easily reproduced 
in my class-room, when the sunlight employed to form a rainbow 
in fine spray is made to pass first through a large vessel with parallel 
glass sides, containing water and a little milk. This arrangement 
imitates very closely the circumstances of the 10th January. 
By J. Christison , Esq. 
I saw it first at Craigie Hall, five miles west of Edinburgh, about 
11.30 or thereby. At first it did not make much impression, as the 
house front runs east and west, and I was standing at the front 
door, and consequently only saw half of the bow, and took it to be 
an accidental arrangement of the light clouds that covered most of 
the sky. By and by the idea of its being a rainbow struck me, and 
a move out from the house showed the full bow. I noticed it off 
and on for about an hour. Sometimes it was indistinct, but gene- 
rally it was evident enough to attract attention at once. I did not, 
however, at any time see anything like clear definition of outline. 
There was always a sort of wavy indistinctness. 
As to colour, I tried hard to convince myself I made it out, but 
without effect, and am quite satisfied there was none at any of the 
periods I looked at the bow. One of the party at Craigie Hall 
thought he made out colour, but on his pointing out the part where 
he thought it was visible I was satisfied that it was only a break in 
the bow, with a bit of very light blue sky showing through. I did 
not notice it after 12.30 or 12.45, as I was indoors. 
It was pretty hard frost all the time. The only effect the sun 
had was to disperse a little of the hoar-frost, which was thick and 
heavy out there, and to make a few of the flat stones among the 
