1. The date of Faujas's visit to Datchet is not stated directly and requires some inference. Although it is commonly acknowledged that the year of Faujas's tour was 1784, he does not actually mention the year anywhere in the narrative. However, shortly before he visited the Herschels Faujas attended a meeting of the Royal Society of London, at which the Elector Palatine of Bavaria was admitted as a member; see Voyage (ref. 1), i, 60–63; Travels (ref. 2), i, 52–54. According to The record of the Royal Society of London for the Promotion of Natural Knowledge (4th edn, London, 1940), 431, this election occurred on 12 August 1784. Faujas subsequently visited the country house of Joseph BanksSir “on the 15th of August” (one of the few dates Faujas explicitly provides). After dining with Banks, “at seven in the evening … I took leave of Sir Joseph, and set off to meet William Herschel, who expected me…. The house in which Mr. Herschel makes his observations … is about twenty miles distant from the house of Joseph BanksSir. … I arrived at Mr. Herschel's about ten o'clock” (Voyage (ref. 1), i, 69–71, 74; Travels (ref. 2), i, 59–60, 63). So we can say with some certainty that Faujas arrived at Datchet on 15 August 1784 and observed into the morning of 16 August. Unfortunately the Herschels' Visitors Book, currently on loan to the William Herschel Museum at Bath, was not yet in full use at this early date.
2. “On the Power of Penetrating into Space”: The Telescopes of William Herschel