they fought in the
dark, "_in tenebris densis_"; and it is a nice problem to shave off a nose
in the dark, without any other harm.--A. De M.

Was this T. B. Laurus Joannes Baptista Laurus or Giovanni Battista Lauro
(1581-1621), the poet and writer?

[780] See note 117, page 76.

[781] Referring to Kepler's celebrated law of planetary motion. He had
previously wasted his time on analogies between the planetary orbits and
the polyhedrons.--A. De M.

[782] See note 117, page 76.

[783] "It does move though."

[784] As great a lie as ever was told: but in 1800 a compliment to Newton
without a fling at Descartes would have been held a lopsided structure.--A.
De M.

[785] Jean-le-Rond D'Alembert (1717-1783), the foundling who was left on
the steps of Jean-le-Rond in Paris, and who became one of the greatest
mathematical physicists and astronomers of his century.

[786] Leonhard Euler (1707-1783), friend of the Bernoullis, the greatest of
Swiss mathematicians, prominent in the theory of numbers, and known for
discoveries in all lines of mathematics as then studied.

[787] See notes 478, 479, page 219.

[788] See note 621, page 288.

[789] See note 584, page 255.

[790] The _siderial_ day is about four minutes short of the solar; there
are 366 sidereal days in the year.--A. De M.

[791] The founding of the London Mathematical Society is discussed by Mrs.
De Morgan in her _Memoir_ (p. 281). The idea came from a conversation
between her brilliant son, George Campbell De Morgan, and his friend Arthur
Cowper Ranyard in 1864. The meeting of organization was held on Nov. 7,
1864, with Professor De Morgan in the chair, and the first regular meeting
on January 16, 1865.

[792] See note 33, page 43.

[793] See note 119, page 80.

[794] John Russell Hind (b. 1823), the astronomer. Between 1847 and 1854 he
discovered ten planetoids.

[795] Sir Roderick Impey Murchison (1792-1871), the great geologist. He was
knighted in 1846 and devoted the latter part of his life to the work of the
Royal Geographical Society and to the geology of Scotland.

[796] Friedrich Wilhelm Bessel (1784-1846), the astronomer and physicist.
He was professor of astronomy at Koenigsberg.

[797] This was the _Reduction of the Observations of Planets made ... from
1750 to 1830: computed ... under the superintendence of George Biddell
Airy_ (1848). See note 129, page 85.

[798] The expense of this magnificent work was defrayed by Government
gr