1874.] Optical Phenomena of the Atmosphere. 35 
triple one produced by reflection from the surface of water— 
seen of course in calm weather. I may add to these an 
observation of a bow, which was almost devoid of colouring, 
and divided into separate rings, four or five in number, 
concentric, and decreasing in width towards the centre,* so 
that the innermost was almost invisible. These rings were 
near together; and the originating cloud seemed of low 
altitude. 
On another occasion I have observed a bow in which the 
outline was decidedly broken and unsymmetrical. This was 
also in the cumulus cloud, and in stormy weather. 
I now pass on to the forms of halo and mock sun: two 
of the latter were seen during the winter and spring of 1872. 
The first was imperfect in definition, as seen from Aigburth, 
about 434 miles south of Liverpool. This, though not a 
brilliant form, is worthy of record from the fact of its 
having been seen at stations widely distant from each other. 
It was described in the ‘‘ Times,” as seen at Meath, in Ireland. 
On comparing notes, I found that this description agreed in 
several points with the observation made by myself. The 
mock sun as it appeared near Liverpool was of an oval 
‘form, and situated vertically over the real sun. It lay 
at the point of contact of two arcs of halos tangent to each 
other. There was no cloud in the sky, only a slight haze, 
such as occurs after heavy dew and hoar-frost. This 
occurred about g.10 on the morning of Jan. 22. There 
had been a slight frost during the night. 
The phenomenon having been observed at several places 
some hundreds of miles apart, the originating crystals must 
have been of unusual altitude and extent. In passing, I 
may remark that the height of mock suns is probably very 
inconstant. ‘Thus, in the cold weather of spring (1871), I 
was fortunate enough to take an observation of the sudden 
formation of a well defined ball of prismatic light, which 
owed its existence to the passage of a rapidly moving 
cumulus cloud. This could scarcely have been higher than 
5 or 6 miles at the most. The mock sun was very similar, 
both in form and position, to that described by me in the 
““People’s Magazine” (February, 1872)—and it appeared 
and disappeared with the cumulus cloud. The weather 
changed to heavy rain on the day following the mock sun 
oF jan, 22, 1872. 
The next instance, of which I took more careful notice, 
* The outer ring was about half the width of an ordinary rainbow, and 
the inner ones became narrower by a fixed proportion. 
