Venus, which we had the good fortune to view from Dunsink Observatory on
the afternoon of the 6th of December, 1882.

The morning of the eventful day appeared to be about as unfavourable
for a grand astronomical spectacle as could well be imagined. Snow, a
couple of inches thick, covered the ground, and more was falling, with
but little intermission, all the forenoon. It seemed almost hopeless
that a view of the phenomenon could be obtained from that observatory;
but it is well in such cases to bear in mind the injunction given to the
observers on a celebrated eclipse expedition. They were instructed, no
matter what the day should be like, that they were to make all their
preparations precisely as they would have done were the sun shining with
undimmed splendour. By this advice no doubt many observers have
profited; and we acted upon it with very considerable success.

There were at that time at the observatory two equatorials, one of them
an old, but tolerably good, instrument, of about six inches aperture;
the other the great South equatorial, of twelve inches aperture, already
referred to. At eleven o'clock the day looked worse than ever; but we at
once proceeded to make all ready. I stationed Mr. Rambaut at the small
equatorial, while I myself took charge of the South instrument. The snow
was still falling when the domes were opened; but, according to our
prearranged scheme, the telescopes were directed, not indeed upon the
sun, but to the place where we knew the sun was, and the clockwork was
set in motion which carried round the telescopes, still constantly
pointing towards the invisible sun. The predicted time of the transit
had not yet arrived.

The eye-piece employed on the South equatorial must also receive a brief
notice. It will, of course, be obvious that the full glare of the sun
has to be greatly mitigated before the eye can view it with impunity.
The light from the sun falls upon a piece of transparent glass inclined
at a certain angle, and the chief portion of the sun's heat, as well as
a certain amount of its light, pass through the glass and are lost. A
certain fraction of the light is, however, reflected from the glass, and
enters the eye-piece. This light is already much reduced in intensity,
but it undergoes as much further reduction as we please by an ingenious
contrivance. The glass which reflects the light does so at what is
called the polarising angle, and between the eye-piece and the eye is