iles an hour. Betsy declares that it was the most agreeable
travelling that she ever had.

Yesterday (Saturday) Caroline drove Betsy and Miss Barnes drove me to
Clay Cross to see the works at the great railroad tunnel there. Coming
from the north, the railroad passes up the Chesterfield valley close
by the town and continues up the same valley, till it is necessary for
it to enter the valley which runs the opposite way towards Buttersley:
the tunnel passes under the high ground between these two vallies: so
that it is in reality at the water-shed: it is to be I think more than
a mile long, and when finished 27 feet clear in height, so it is a
grand place. We saw the preparations for a blast, and heard it fired:
the ladies stopping their ears in due form.

1839

"Cambridge Observatory:--On Mar. 7th I went to Cambridge on the
business of the Northumberland Telescope: I was subsequently engaged
on the accounts, and on Aug. 16th I finally resigned it to
Prof. Challis, who accepted it on Aug. 19th. On Sept. 11th I
communicated its completion and the settlement of accounts to the Duke
of Northumberland. The total expense was _L1938. 9s. 2d._ + 15000
francs for the object-glass.

"At Greenwich Observatory:--On Jan. 3rd I received the last revise of
the 1837 Observations, and on Jan. 8th the first sheet for 1838.--In
July I report on selection from a long list of chronometers which had
been on trial, and on Sept. 2nd I pointed out to Capt. Beaufort that
the system of offering only one price would be ruinous to the
manufacture of chronometers, and to the character of those supplied to
the Admiralty: and that I would undertake any trouble of classifying
the chronometers tried. This letter introduced the system still in use
(1871), which has been most beneficial to the manufacture. On
Sept. 11th I proposed that all trials begin in the first week of
January: this also has been in use as an established system to the
present time.--It was pointed out to me that a certain chronometer was
affected by external magnetic power. I remedied this by placing under
it a free compass magnet: a stand was specially prepared for it. I
have never found another chronometer sensibly affected by
magnetism.--In November and December I tried my new double-image
micrometer.--Between May 16th and Oct. 13th a fireproof room was
constructed in the southern part of the quadrant room; and in November
a small shed was er