Sir,--Betterton's _Instructions on the Art of Playing and Public Speaking_, queried in your 5th Number, were published by the well-known dramatic critic, Charles Gildon, and form a portion of his _Life of Betterton_. As this work is little known, I shall quote the title at length:--"The Life of Mr. Thomas Betterton, the late eminent Tragedian, wherein the Action and Utterance of the Stage, Bar, and Pulpit, are distinctly considered; with the judgment of the late ingenious Monsieur de St. Evremond, upon the Italian and French Music and Operas, in a Letter to the Duke of Buckingham. To which is added, The Amorous Widow, or the Wanton Wife, a Comedy, written by Mr. Betterton, now first printed from the Original Copy. _London, Printed for Robert Gosling, at the Miter, near the Inner Temple Gate in Fleet Street_, 1710. 8vo." Gildon was intimately acquainted with Betterton, and he gives an interesting account of a visit paid to that great actor, the year before his death, at his country house at Reading. It was on this occasion that Gildon came into the possession of Betterton's manuscripts. Thirty-one years after the publication of Betterton's Life, Curll, the notorious bookseller, put forth a mutilated copy of the _Instructions on Playing_, in a work bearing the following title:--"The History of the English Stage, from the Restauration to the Present Time, Including the Lives, Character, and Amours, of the most Eminent Actors and Actresses; with Instructions for Public Speaking, wherein the Action and Utterance of the Bar, Stage, and Pulpit, are distinctly considered. By Thomas Betterton. _London, Printed for E. Curll, at Pope's Head in Rose-Street, Covent Garden_, 1741. 8vo." From this title it would appear (as indeed Curll wished it) that Betterton was the author of the entire work; but he is only accountable for the brief _Instructions for Public Speaking_, which, as before stated, were pillaged from Gildon. Reverting to Colley Cibber's _Lives_, I beg to point out a curious and rare tract in connection with them, entitled, "A Brief Supplement to Colley Cibber, Esq.; his Lives of the Late Famous Actors and Actresses. By Anthony (vulgò Tony) Aston. Printed for the Author. 8vo. pp. 24." The copy now before me, which was Isaac Reed's, sold at his sale for 2_l_. 5_s_. It is reprinted in a literary journal called _The Cabinet_, and in Bell-chambers' excellent edition of Cibber's _Apology_. Whilst on the subject of the stage, I should be glad if any of your correspondents could inform me what has become of "Dick Leveridge's History of the Stage and Actors in his own Time?" Leveridge himself informed Oldys that he had compiled such a work, and Oldys, with his usual care, noted the fact in one of his numerous memorandum books. I have been long engaged in a history of _The Life and Times of Henry Purcell_, and the said MS., if it could be recovered, would, without doubt, enlighten us much upon the subject of Purcell's career as a dramatic composer.