he
mine of Dolcoath near Camborne in Cornwall would be a better place for
the experiment. Dr Paris wrote to me repeatedly, and ultimately we
resolved on trying it there. In my papers on Mar. 21st are various
investigations about attractions in both mines. On Apr. 3rd I went to
London, principally to arrange about Dolcoath, and during April and
May I was engaged in correspondence with Sir H. Davy (President of
the Royal Society), Mr Herschel, and Dr Young (Secretary of the Board
of Longitude) about the loan of instruments and pendulums. On
Apr. 23rd I was practising pendulum-observations (by coincidence); and
about this time repeatedly practised transits with a small instrument
lent by Mr Sheepshanks (with whom my acquaintance must have begun no
long time before) which was erected under a tent in the Fellows'
Walks. On my quires I find various schemes for graduating thermometers
for pendulum experiments.

"I find also Notes of examination of my brother William, who had come
to College last October; and a great deal of correspondence with my
mother and sister and Mr Case, a lawyer, about a troublesome business
with Mr Cropley, an old friend of G. Biddell, to whom my father had
lent _L500_ and whose affairs were in Chancery.

"My lectures in this term were to the Junior Sophs from Apr. 10th to
May 13th: they were six in number and not very regular. On Apr. 28th I
sent to Mawman the copy of my Trigonometry for the Encyclopaedia
Metropolitana, for which I received _L42_. I received notice from the
Press Syndicate that the price of my Mathematical Tracts was fixed at
_6s. 6d._: I sold the edition to Deighton for _L70_, and it was
immediately published. About this time I have letters from Mr Herschel
and Sir H. Davy about a Paper to be presented to the Royal Society--I
suppose about the Figure of the Earth to the 2nd order of ellipticity,
which was read to the Royal Society on June 15th.

"On Saturday, May 13th, 1826, I went to London on the way to Dolcoath,
and received four chronometers from the Royal Observatory,
Greenwich. I travelled by Devonport and Falmouth to Camborne, where I
arrived on May 20th and dined at the count-house dinner at the mine. I
was accompanied by Ibbotson, who was engaged as a pupil, and intended
for an engineer. On May 24th Whewell arrived, and we took a pendulum
and clock down, and on the 30th commenced the observation of
coincidences in earnest. This work, with the changing of the
pendulums, a