This chapter deals with four works – three shorter publications and one unpublished document – in chronological order of publication or creation: Gunn's 1790 translation of a work by Antonio Borghese (Gunn/Borghese), a translation attributed to Gunn of a German biography of the cellist Johann Christoph Schetky, Gunn's Essay (Harmony), and his Essay (Piano). The two essays are an extension of his earlier pedagogical works; the translations, though less significant in terms of their content, show Gunn at work as an editor.

❧ Gunn/Borghese

In 1785–6 the Italian composer Antonio Borghese published a work in French entitled L’art musical … traduites de l’italien par l’auteur. Gunn translated this work under the title A General System of Music. His title page is dated 1790, and the preface is dated 1 April 1790. Some confusion has existed over the claim on Gunn's title page that his English translation was made not from the French but from an Italian text by Borghese’s:

At first sight, Gunn's translation would be the only English version of a lost Italian work on music theory, and indeed it would constitute the only evidence that the Italian text even existed. This has led to some uncertainty as to the language of Borghese's original; the Gunn entry in GMO gives it as Italian, but that is contradicted by the article on Borghese. An early DNB reference seems to have created this confusion: ‘In 1790 Gunn translated from the Italian A. D. R. Borghese's “New and General System of Music” (originally published in French, 1788, Paris).’ In fact, the 1912 British Museum catalogue of printed music clarified this, saying that ‘the Italian version was never published’. For Gunn's English version Borghese adds an explanation that his book had been published in France, without success.