[639] Parsey also wrote _The Art of Miniature Painting on Ivory_ (1831),
_Perspective Rectified_ (1836), and _The Science of Vision_ (1840), the
third being a revision of the second.

[640] William Ritchie (1790-1837) was a physicist who had studied at Paris
under Biot and Gay-Lussac. He contributed several papers on electricity,
heat, and elasticity, and was looked upon as a good experimenter. Besides
the geometry he wrote the _Principles of the Differential and Integral
Calculus_ (1836).

[641] Alfred Day (1810-1849) was a man who was about fifty years ahead of
his time in his attempt to get at the logical foundations of geometry. It
is true that he laid himself open to criticism, but his work was by no
means bad. He also wrote _A Treatise on Harmony_ (1849, second edition
1885), _The Rotation of the Pendulum_ (1851), and several works on Greek
and Latin Grammar.

[642] Walter Forman wrote a number of controversial tracts. His first seems
to have been _A plan for improving the Revenue without adding to the
burdens of the people_, a letter to Canning in 1813. He also wrote _A New
Theory of the Tides_ (1822). His _Letter to Lord John Russell, on Lord
Brougham's most extraordinary conduct; and another to Sir J. Herschel, on
the application of Kepler's third law_ appeared in 1832.

[643] Lord John Russell (1792-1878) first Earl Russell, was one of the
strongest supporters of the reform measures of the early Victorian period.
He became prime minister in 1847, and again in 1865.

[644] Lauder seems never to have written anything else.

[645] See note 22, page 40.

[646] The names of Alphonso Cano de Molina, Yvon, and Robert Sara have no
standing in the history of the subject beyond what would be inferred from
De Morgan's remark.

[647] Claude Mydorge (1585-1647), an intimate friend of Descartes, was a
dilletante in mathematics who read much but accomplished little. His
_Recreations mathematiques_ is his chief work. Boncompagni published the
"Problemes de Mydorge" in his _Bulletino_.

[648] Claude Hardy was born towards the end of the 16th century and died at
Paris in 1678. In 1625 he edited the _Data Euclidis_, publishing the Greek
text with a Latin translation. He was a friend of Mydorge and Descartes,
but an opponent of Fermat.

[649] That is, in the _Bibliotheca Realis_ of Martin Lipen, or Lipenius
(1630-1692), which appeared in six folio volumes, at Frankfort, 1675-1685.

[650] See note 29, page 43.

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