distances. To an observer upon a high hill, a plain below
him appears to become more distant. Although what has been called the
descent of the clouds (that is to say their appearance of growing
proximity) is most manifest immediately before the totality, yet a sense
of growing nearness may sometimes be noticed a very considerable time
before the total phase is reached.

Whilst on the subject of clouds, it may be mentioned that although there
is in the vault of heaven generally during the total phase an
appreciable sensation of black darkness, more or less absolute, that is
to say, either blackish or greyish, yet in certain regions of the sky,
(generally in the direction of the horizon) the clouds, when there are
any, often exhibit colours in strata, orange hue below and red above,
with indigo or grey or black higher up still, right away to the Sun's
place. The cause of these differences is to be found in the fact that
the lower part of the atmosphere within the area of the Moon's shadow
is, under the circumstances in question, illuminated by light which
having passed through many miles of atmosphere near to the Earth's
surface, has lost much from the violet end of its spectrum, leaving an
undue proportion of the red end.

On certain occasions iridescent or rainbow-tinted clouds may be seen in
the vicinity of the Sun, either before, or during, or after totality,
depending on circumstances unknown. Such clouds have been observed at
all these three stages of a total eclipse. The effects of course are
atmospheric, and have no physical connection with either Sun or Moon.

THE DARKNESS OF TOTALITY.

With respect to the general darkness which prevails during totality,
great discrepancies appear in the accounts, not only as between
different eclipses, but in respect of the same eclipse observed by
different people at different places. Perhaps the commonest test applied
by most observers is that of the facility or difficulty of reading the
faces of chronometers or watches. Sometimes this is done readily, at
other times with difficulty. In India in 1868, one observer stated that
it was impossible to recognise a person's face three yards off, and
lamplight was needed for reading his chronometer. On the other hand in
Spain in 1860, it was noted that a thermometer, as well as the finest
hand-writing, could be read easily. The foregoing remarks apply to the
state of things in the open air. In 1860, it was