“The grinding of specula used to be performed by the hand, no machinery having been deemed sufficiently exact. The tool on which they were shaped having been turned to the required form, and covered with coarse emery and water, they were ground on it to the necessary figure, and afterwards polished by means of putty or oxide of tin, or pitch spread as a covering to the same tool in the place of the emery. To grind a speculum of six or eight inches in diameter was a work of no ordinary labour; and such a one used to be considered of great size.”—“_Lord Rosse’s Telescopes_,” 1844. Footnote 7: He was elected a Fellow of the Royal Society, Dec. 6, 1781. Footnote 8: “About the latter end of this month [December, 1779] I happened to be engaged in a series of observations on the lunar mountains, and the moon being in front of my house, late in the evening I brought my seven-feet reflector into the street, and directed it to the object of my observations. Whilst I was looking into the telescope, a gentleman coming by the place where I was stationed, stopped to look at the instrument. When I took my eye off the telescope, he very politely asked if he might be permitted to look in, and this being immediately conceded, he expressed great satisfaction at the view. Next morning the gentleman, who proved to be Dr. Watson, jun. (now Sir William), called at my house to thank me for my civility in showing him the moon, and told me that there was a Literary Society then forming at Bath, and invited me to become a member of it, to which I readily consented.”—_Sir W. Herschel’s Journal._ This occurred at a house in River Street, which was soon changed for 19, New King Street. Footnote 9: George Griesbach, who with the rest of the family settled in England, where they all did well, their musical talents and connections bringing them a good deal under the notice of the Court. Mr. G. Griesbach’s youngest daughter, Elizabeth, became the wife of Mr. Waterhouse, of the British Museum. She died in 1874. Footnote 10: This eminent astronomer made inquiries after Miss Herschel long years afterwards, as is related in the correspondence. See letter from Sir J. Herschel, dated Catania, 1824, p. 174. Footnote 11: This is the last time that the name of Jacob Herschel appears. Footnote 12: Dr. Herschel married Mary, only child of Mr. James Baldwin, a merchant of the City of London, and widow of John Pitt, Esq., by whom she had one son, who died in early youth. She was a lady of singular amiability and gentleness of character. The jointure which she brought enabled Dr. Herschel to pursue his scientific career without any anxiety about money matters. Footnote 13: M. De la Lande’s name was _Jerome Le Français dit de la Lande_; it is to himself, therefore, that he here refers. The letter is addressed “Mlle. Caroline Herschel, Astronome Célèbre, Slough.” Footnote 14: