A few posts back, I mentioned the first essay in Hart & Khovacs' TREE OF TALES: TOLKIEN, LITERATURE, AND THEOLOGY --i.e., Rachel Hart's "Tolkien, St. Andrews, and Dragons"-- in the course of which I made reference to
"Tolkien's 1947 St. Andrews lecture which became 'On Fairy-Stories'"
However, the next day in the Comments David said
"Oh, I do hope they didn't say Tolkien gave the lecture in 1947."
In fact, no, she doesn't. That mistake was entirely my own, absent-mindedly typing in the date of the facsimile letter she reproduces, which Tolkien sent to Professor T. Malcolm Knox with a presentation copy of ESSAYS PRESENTED TO CHARLES WILLIAMS on 17 December 1947. Hart gives behind-the-scenes background on the Andrew Lang lecture series, including the date Tolkien delivered his own lecture (Wednesday, 8th March, 1939), the information that JRRT was one of three potential speakers that year (the first two of whom turned St Andrews down*), how much Tolkien's honorarium was (thirty pounds), and the date upon which he was issued the invitation. Since the latter date does not appear in the Scull-Hammond chronology, which merely notes "There seems to be no record of when the invitation to lecture was sent to Tolkien" (Scull-Hammond, THE J.R.R.TOLKIEN COMPANION & GUIDE, Vol. II: READER'S GUIDE, pages 686-687), here's the date for those (like me) who'll pencil it into their copy: 8th October 1938.
It shd go on page 222 of Vol. I: CHRONOLOGY --or, rather, the entry that currently appears on page 211 shd be moved to page 222 instead under this specific date.
*These were Sir Gilbert Murray, who would eventually deliver the next lecture in 1947, the series having fallen into abeyance during the war years, and Lord Hugh Macmillan, who delivered the 1948 lecture.