[323] Thomas Weddle (1817-1853) was, at the time of publishing this paper, a teacher in a private school. In 1851 he became professor of mathematics at Sandhurst. He contributed several papers to the _Cambridge and Dublin Mathematical Journal_, chiefly on geometry. [324] See Vol. II, page 109, note 205. [325] See Vol. II, page 66, note 143. [326] See Vol. II, page 151, note 268. [327] George Barrett (1752-1821) worked from 1786 to 1811 on a set of life insurance and annuity tables. He invented a plan known as the "columnar method" for the construction of such tables, and as De Morgan states, this was published by Francis Baily, appearing in the appendix to his work on annuities, in the edition of 1813. Some of his tables were used in Babbage's _Comparative View of the various Institutions for the Assurance of Lives_ (1826). [328] See Vol. I, page 309, note 2 {670}. [329] This was his _Practical short and direct Method of Calculating the Logarithm of any given Number, and the Number corresponding to any given Logarithm_ (1849). [330] This is William Neile (1637-1670), grandson of Richard Neile (not Neal), Archbishop of York. At the age of 19, in 1657, he gave the first rectification of the semicubical parabola. Although he communicated it to Brouncker, Wren, and others, it was not published until 1639, when it appeared in John Wallis's _De Cycloide_. [331] I myself "was a considerable part." [332] He also wrote _A Glance at the Universe_ ("2d thousand" in 1862), and _The Resurrection Body_ (1869). [333] See Vol. I, page 63, note 1 {74}. [334] As Swift gave it in his _Poetry. A Rhapsody_, it is as follows: "So, naturalists observe, a flea Has smaller fleas that on him prey; And these have smaller still to bite 'em. And so proceed _ad infinitum_." [335] Perhaps 1,600,000,000 years, if Boltwood's recent computations based on radium disintegration stand the test. This would mean, according to MacCurdy's estimate, 60,000,000 years since life first appeared on the earth. [336] De Morgan wrote better than he knew, for this work, the _Allgemeine Encyclopaedie der Wissenschaften und Kuenste_, begun at Leipsic in 1818, is still (1913) unfinished. Section I, A-G, consists of 99 parts in 56 volumes; Section II, H-N, consists of 43 volumes and is not yet completed; and Section III, O-Z, consists of 25 volumes thus far, with most of the work still to be done. Johann Samuel Ersch (1766-1828), the founder, was head librarian at Halle. Johann Gottfried Gruber (1774-1851), his associate, was professor of philosophy at the same university. [337] William Howitt (1792-1879) was a poet, a spiritualist, and a miscellaneous writer. He and his wife became spiritualists about 1850. He wrote numerous popular works on travel, nature and history. [338] See Vol. II, page 55, note 108. [339] As will be inferred from the text, C. D. was Mrs. De Morgan, and A. B. was De Morgan.