ece which
would be necessary: also on spherical aberrations and Saturn's
figure. On my quires at Cambridge I was working on the effects of
separating the object-glass lenses, with the view of correcting the
secondary spectrum: and on Jan. 31st I received some numbers (indices
of refraction) from Mr Herschel, and reference to Fraunhofer's
numbers.

"About this time it was contemplated to add to the Royal Observatory
of Greenwich two assistants of superior education. Whether this
scheme was entertained by the Admiralty, the Board of Longitude, or
the Royal Society, I do not know. Somehow (I think through Mr
Peacock) a message from Mr Herschel was conveyed to me, acquainting me
of this, and suggesting that I should be an excellent person for the
principal place. To procure information, I went to London on Saturday,
Feb. 7th, sleeping at Mr South's, to be present at one of Sir Humphrey
Davy's Saturday evening soirees (they were then held every Saturday),
and to enquire of Sir H. Davy and Dr Young. When I found that
succession to the post of Astronomer Royal was not considered as
distinctly a consequence of it, I took it coolly, and returned the
next night. The whole proposal came to nothing.

"At this time I was engaged upon differential equations, mountain
barometer problem and determination of the height of the Gogmagogs and
several other points, investigations connected with Laplace's
calculus, spherical aberration in different planes, geology
(especially regarding Derbyshire, which I proposed to visit), and much
of optics. I wrote a draft of my Paper on the figure of Saturn, and on
Mar. 15th, 1824, it was read at the Philosophical Society under the
title of 'On the figure assumed by a fluid homogeneous mass, whose
particles are acted on by their mutual attraction, and by small
extraneous forces,' and is printed in their Memoirs. I also wrote a
draft of my Paper on Achromatic Eye-pieces, and on May 17th, 1824, it
was read at the Philosophical Society under the title of 'On the
Principles and Construction of the Achromatic Eye-pieces of
Telescopes, and on the Achromatism of Microscopes,' including also the
effects of separating the lenses of the object-glass. It is printed in
their Memoirs.

"Amongst miscellaneous matters I find that on Mar. 22nd of this year I
began regularly making extracts from the books of the Book Society, a
practice which I continued to March 1826. On Mar. 27th, a very rainy
day, I walked to Bu