Joao de Souza Freire de Araujo Borges Da Veiga, 1766

BORGES DA VEIGA, Joao de Souza Freire de Araujo and BORGES DA VEIGA, Joze de Araujo Souza Freire. Manuscript, "Dialogo epistolar astronomico sobre o cometa apparecido em Lamego as da Abril e observado aze o dia 9. dao anno de 1766." n.p., 9 April 1766.

In Portuguese. 11 pages, 345 x 228mm. pen and ink drawing of a comet on the title page (mild dust-soiling). Stitched and sewn. Housed, but not bound, in contemporary marbled boards.

An unpublished Portuguese treatise on the 1766 Comet (D/1766 G1 Helfenzrieder), which appeared in April of that year and was discovered on 1 April by Helfenzrieder, and independently by Messier, Cassini de Thury, and others. This treatise gives a detailed account of the observations made by the authors from their observatory set up on the mountain of Queimada near Lamego in Portugal. The authors also present a chronological catalogue of previous observations of comets from 1500 on, and cite numerous authors, including Apianus, Kepler, Gassendi, Cassini, Hevelius, Halley, Newton, Clairaut, and members of the Académie Royal des Sciences. The title bears the initials of the authors, who have signed and dated the manuscript in full at the end, and dedicated it to an unidentified noble recipient. The authors were pioneer climatologists as well as being accomplished astronomers. "To the best of our knowledge, the earliest [meteorological] records undertaken in continental Portugal were carried out by Joao de Sousa Freire de Araujo Borges da Veiga … in Lamego, from 1770 until 1784." (M.J. Alcofornado et al, "Early Portuguese meteorological measurements (18th century). Climate of the Past 8 (2012), p. 358.