34 Optical Phenomena of the Atmosphere. [January, 
III. OBSERVATIONS ON THE OPTICAL 
PHENOMENA OF THE ATMOSPHERE. 
By S. BARBER, F.M.S.. 
qs) URING the first quarter of the year 1872, many 
d— remarkable optical phenomena were observed in the 
neighbourhood of Liverpool; and as I have on 
previous occasions published remarks bearing on the 
prognostic value of these appearances,* it seemed advisable 
to colleét and compare such notes as may bear upon the 
prediction of weather, and help to elucidate the questions 
that have been raised as to the origin, and varieties of halos 
and parhelia. The subject, certainly, is one of the highest 
interest, both in relation to the various crystalline forms of 
water and the constituent particles of the various forms of 
cloud. A beam of light passing through the upper atmo- 
sphere may reveal to us, by the laws of refraction, the 
degree of congelation of vapour floating ten or twenty miles 
away. The investigation of the cirrus and cirro-cumulus 
being admittedly of the highest importance in relation to 
the movements of the great atmospheric currents, it seems 
surprising that the optical laws and phenomena bearing on 
their constitution should not have received more attention 
at the hands of meteorologists. 
Before passing on to the proper subject of this paper— 
viz., halos and parhelia—I may remark that the rainbow, 
which appears to have been so thoroughly investigated, 
exhibits at times more variety, both in form and colouring, 
than most writers seem to be aware of. ‘These varieties 
will be found—like those of the halo—to have a relation to 
the general atmospheric conditions of the time. For example, 
I have frequently noticed that the tendency to an irregular 
outline, and the appearance of double bows, &c., are mostly 
connected with stormy and squally weather. A dark day in 
autumn, with low-flying nimbo-cumulus, and driving rain, 
will sometimes exhibit, in its transient gleams of sunshine, 
most curious and unexpected forms. On such occasions, 
though the outlines are more remarkable, the colouring is 
not so brilliant and decided as in calmer weather. 
In the last “Quarterly Journal of the Meteorological 
Society,” Mr. Scott gives notes of a double rainbow, with 
reversed colours; and Mr. Lecky adds an account of a 
* Quarterly Journal of Science, No. 26. 
