Regras de acompanhar para cravo, ou orgaõ, e ainde tambem para qualquer outro instrumento de vozes, reduzidas a breve methodo, e fácil percepçaõ.Lisbon, Francisco Luís Ameno, 1758. 4to (21 x 15 cm). With 12 pages of engraved music printed from 12 copper plates on both sides of 6 inserted leaves (mostly polyphonic music with 4 double staves - G and F clef - per page). Further with a full-page engraved dial showing the 12 intervals in all major and minor keys, including diminished and augmented intervals (lacking the inner rotating dial with the twelve notes: photocopy supplied), a woodcut ornament on the title-page, 2 woodcut decorated initials (from 2 different series) and 2 woodcut head pieces. Contemporary, richly gold-tooled red goatskin morocco.

[8], “39” [= 47] [pp. 45-47 numbered as 37-39], [1 blank], [2], [2 blank] pp.First and only edition of an educational work with rules and a method for accompaniment for harpsichord, organ or other vocal instruments. It was written and composed to be short and easy to understand, for the use of beginners. The illustrations of musical notation were added to clarify the text and to put the theory into practice. Alberto José Gomes da Silva (ca. 1713?-1795) was a Portuguese classical organist and composer. He is known not especially for the present work, published in Lisbon in 1758, but also for several operas, sonatas for piano, and other musical works. One of his operas was staged in a public theatre ("Teatro da Rua dos Condes") in Lisbon in 1775.The present work stands out in relation to other 18th century works on music theory, as the only known Portuguese publication exclusively devoted to the basso continuo and also as the first work printed in Portugal, to present all major and minor scales of the complete chromatic octave. The rotating inner dial (lacking in the present copy, but supplied in a photocopy) shows the twelve notes of the chromatic scale. So one can turn the inner dial to align any chosen note with the fundamental/octave, and the dial will indicate all notes of the scale for its major and minor keys, for example as an aid to transposition. When one note has two different names depending on the scale, it is labelled with both (for example A flat and G sharp). Very slight signs of wear, without affecting the integrity of the binding. Lacking the rotating inner dial for the engraved dial with the musical keys, with a small ink stain on the title-page, a small hole in pp. 5-6, slight browning of the full-page plates, otherwise in very good condition. The binding shows slight signs of wear but is also generally very good. The first 18th-century Portuguese music book on the basso continuo, in a lovely contemporary binding.l Dicionáro Biográfico Caravelas, "SILVA, Alberto José Gomes da"; Inocêncio, I, p. 24 and VIII, p. 23; Joaquim de Vasconcelos (Músicos), II, p. 167.