543 
of Edinburgh) Session 1877 - 78 . 
the smoky veil without the slightest definition of its disc, white 
nevertheless, hut so shorn of its brightness that I could easily look 
it in the face. I was unable to detect anywhere the slightest 
appearance of a shower or rain-cloud. The sun, my place of obser- 
vation, and the summit of the arch, were in the same vertical plane. 
The summit of the arch reached about half-way to the zenith. 
The northern sky on which it was formed was somewhat hazy and 
grey in its lower region, but blue-grey, and tolerably clear in the 
region of the upper two-thirds of the arch. 
In form the arch was identical with that of an ordinary rainbow, 
except that I thought it considerably broader ; and its edges were 
in many places somewhat broken, so that it had exactly the appear- 
ance as if the sun had gathered in an arch a number of little woolly 
cloudlets. On minute search I could not detect any trace of colour 
from end to end. I asked the opinion on this point of two gentle- 
men whom I met at the lowest part of the road, at the wall between 
the road and the river, and one of them thought he could detect a 
very faint trace of colour over a small space at the extremity of the 
western limb. As the absence of colour, however, was the main 
phenomenon, I scanned the whole curve again and again with great 
attention, but could see no coloration anywhere. 
At this lowest point of the road the edges of the bow were seen 
much more defined and sharp than when I first noticed it. As I 
advanced up the gentle slope from Warriston bridge towards the 
Botanic Garden, the summit of the arch began to break up, and to 
present the appearance of irregular flimsy cloudlets ascending in the 
sky above it. But before reaching the Garden gate the whole arch 
again formed an unbroken bow, and with both edges sharply defined 
like those of a common rainbow. At the same time a similar 
secondary arch had begun to form below the principal one, only 
half its width, and much closer to its neighbour than I remember 
to have seen in a double rainbow of the ordinarv kind. 
«/ 
On returning homeward, about fifteen minutes later, I still 
observed, on issuing from the Garden, a sharply-defined colourless 
principal bow, and now a complete secondary one under every part 
of the bow visible from the roadway. As I proceeded southward 
every now and then the upper region of the bow seemed to be 
breaking up, and this appearance was very marked when I reached 
