dates of their first and last appearances entered
up to the present time. Areas of spots have been
measured, and the measures have been reduced to millionths
of the Sun’s visible hemisphere.—The
examination of the readings of the deep-sunk thermometers
from 1846 to 1873 has exhibited some laws which had
been sufficiently established before this time, and
some which were less known. Among the former
were the successive retardations of seasons in successive
descents, amounting to about four months at the depth
of 25 feet; and the successive diminutions of the
annual range of temperature. Among the latter
is the character of the changes from year to year,
which the great length of this series of observations
brings well to light. It is found that from year
to year the mean temperature of the surface for the
year, varying by three or four degrees of Fahrenheit,
follows in its changes the mean temperature of the
atmosphere for the year, and that the changes of annual
temperature are propagated downwards, retarded in phase
and diminishing in amount of change, in the same manner
(though probably not following the same law) as the
season changes. The inference from this is, that
changes of temperature come entirely from the exterior
and in no discoverable degree from the interior; an
inference which may be important in regard both to
solar action and to geology. —Referring
to the Transit of Venus observations: In the
astronomical part of the reductions, there has been
great labour and difficulty in the determination of
local sidereal times; some books of observations required
extensive transcription; some instrumental errors
are still uncertain; the latter determinations have
perplexed us so much that we are inclined to believe
that, in spite of the great facilities of reduction
given by the transit instrument, it would be better
to rely on the altazimuth for time-determinations....
In the photographic part, I have confined my attention
entirely to measures of the distance between the centres
of the Sun and Planet, a troublesome and complex operation.—Referring
to the progress of the Numerical Lunar Theory:
With a repetition of grant from the Treasury, I have
usually maintained four junior computers on this work.
The progress, though considerable, has not been so
great as I had hoped, by reason of the excessive personal
pressure upon me during the whole year.—I
wrote a letter of congratulation to Le Verrier on the
completion of his great work of Planetary Tables.—On
May 13th the Queen was at South Kensington, and I
attended to explain the astronomical instruments,
and shewed Her Majesty one of the Transit of Venus
photographs.”
Of private history: He returned from his Playford visit on the 18th of January.—In April there was a two-day trip to Colchester.—From June 13th to July 12th he was travelling in the North of Scotland and the Orkneys with his daughters, staying for a short time with Mr Webster, M.P., at Aberdeen, and with Mr Newall at Newcastle.—In September there was a week’s run to Birkenhead and Keswick.—In November a week’s run to Playford.—From the 13th to 15th of December he was at Cambridge, and on the 28th he went to Playford for the usual winter stay there.