SUPPLEMENTARY REPORT ON METEOROLOGY. 14] 
off presented to the first observer nothing peculiar. The lumi- 
nous haze extended but a short way right and left, but in a ver- 
tical direction it extended through a very considerable angle, 
producing the very singular effect of a train of hazy light. The 
same effects I have seen less perfectly in other localities, but 
generally towards sunset, and only when a considerable space 
intervened between the observer and his shadow. 
309. Similar phenomena have been described by various ob- 
servers, and variously accounted for*. The vertical train of 
light which occasionally accompanies halos, has been explained 
by the reflexion from the bases of vertical crystals;; but as it 
is seen to occur in circumstances such as those mentioned in the 
last paragraph, it must evidently be independent of the existence 
of ice in the air. Fraunhofer has endeavoured to explain it on 
principles of diffraction, and I conceive that it is most likely 
to be explained on some such principle, taking into account the 
abrupt variations of temperature which often take place near 
the ground towards sunset, and which produce strata of air 
very variously charged with moisture in various degrees of con- 
densation, horizontally disposed, and partial reflexion in which 
would undoubtedly tend to produce a diifuse vertical image, such 
as we see on water slightly rippled, when looking across the 
rippled surface. The main cause, however, of this expanded 
vertical image appears to be, that by looking very obliquely 
through a thin stratum of cloudy particles, their apparent di- 
stances will be diminished by the obliquity, and their interstices 
in the same proportion. Diffraction bands will, therefore, ex- 
pand in the direction in which the particles are apparently 
compressed. I have found that such phenomena are accurately 
reproduced by suffering soap-suds to dry upon a plate of glass, 
and then looking at a flame obliquely through it: when viewed 
perpendicularly neither colour nor diffused light appears in one 
direction more than another. 
310. The occurrence of the anthelion itself, or luminous 
point opposite the sun, is not of so easy explanation as some 
writers seem to consider it ; and until it is fully understood, we 
can hardly hope to explain all its modifications. The glory 
* See the observations of Hevelius, Derham and Young, quoted in Young’s 
Lectures, ii. 303, as to the vertical train of light; more lately by Mr. Christie, 
British Association, 7th Report, Sections, p.15. [Mr. Christie’s original commu- 
nication to the Meeting at Cambridge in 1833, contained in a letter to me, 
appears to have fallen aside, and is neither published nor in my possession. ] 
¢ First by Young, also by Babinet (Comptes Rendus, iv. 640), Galle (Pogg. 
xxix. 256), and others. 
¢ Schumacher, Abhandl., iii. 82. 
