This comet, since known as Encke’s, in consequence of that great astronomer having determined its periodicity in 1819 and predicted its triennial return, was discovered, independently, four several times before its identity was recognized, Miss Herschel’s observation of it in 1795 being the second in order of time. Additional interest has since attached to it, in consequence of its gradually diminishing period and the views hence suggested on the economy of the solar system. Footnote 15: The Rev. S. Vince, a mathematician and natural philosopher. Footnote 16: Sir William Watson, M.D., Knight, F.R.S. from 1770 to 1800, when he resigned. He was one of the first members of the Astronomical Society at its foundation in 1821 under the Presidency of William Herschel. His father, also M.D. and Knight, was the eminent botanist and naturalist. He lived much at Dawlish, where the Herschel family frequently went to stay with him. Footnote 17: Alexander Wilson, M.D., professor of practical astronomy in the University of Glasgow, and first propounder of that theory as to the cause and nature of the spots on the sun, which was afterwards fully corroborated and worked out by Sir W. Herschel. Footnote 18: The Prince’s questions were sometimes of a very remarkable kind. On a previous occasion when he “stept in” with a view to having them answered, and was not so fortunate as to find anyone at home, he left the following memorandum: “The Prince of Orange has been at Slough to call at Mr. Herschel’s and to ask him, or if he was not at home to Miss Herschel, if it is true that Mr. Herschel has discovered a new star, whose light was not as that of the common stars, but with swallow tails, as stars in embroidery. He has seen this reported in the newspapers, and wishes to know if there is any foundation to that report.—Slough, the _8th_ of _August_, 1798.—W. Prince of Orange.” Footnote 19: James Lind, M.D., was a Scotchman, who devoted a considerable amount of his time to astronomical observations. Footnote 20: The only child of Dr. Herschel. He afterwards became Sir John Herschel. Miss Herschel was very proud as well as fond of him. He is “my nephew.” Dr. Herschel is usually called “my brother,” in distinction from all the rest of the family. Footnote 21: Mrs. Beckedorff was “the sweet little girl of ten or eleven years old” with whom Miss Herschel had exchanged pleasant greetings when they were both taking lessons in dressmaking from Madame Küster, in Hanover, thirty-five years before. (See p. 22.) Footnote 22: Probably Professor Wales, mathematical master at Christ’s Hospital, author of a mathematical paper published in the “Phil. Trans.,” 1781. Footnote 23: