The life & work of Roger Bacon : an introduction to the Opus majus / by H. Gordon Jones.

  • John Henry Bridges
Date:
1914
Catalogue details

Licence: In copyright

Credit: The life & work of Roger Bacon : an introduction to the Opus majus / by H. Gordon Jones. Source: Wellcome Collection.

    40/180 (page 38)
    and remarks that Paul of Middelburg, who was much occupied with the question of the Calendar, and had treated of it in his work Paulina de recta Paschae celehratione (1513), had made great use of Bacon. ‘ His great volume is more than half thereof written (though not acknowledged), by such order and method generally and particularly as our Roger Bacon laid out for the handling of the matter.’ When we remember that it was Paul of Middelburg by whom Copernicus was urged with a view to this very problem to construct more accurate astronomical tables, we shall gladly acknowledge that here, too. Bacon’s labour was not lost.^ 3. No part of Bacon’s work was more frequently transcribed than his Perspectiva. Based as it was upon the great work of Alhazen, which was itself 1 [‘ That the length of the year was wrongly given in the Julian Calendar must have been known to the small group of Arabian men of science who studied Ptolemy’s Almagest. But that the amount of the error was not matter of common knowledge half a century after the Opus Majus was written, is shown by the passage in Dante (^Paradtso, xxvii. 132-3), where the error is spoken of as being the hundredth part of a day- The difference between and is considerable to those who know Dante’s minute and precise way of dealing with such questions. The mean length of the equinoctial year is 365^, 5>*, 48“, 46®. What Bacon showed was that the Julian Calendar made the year too long by theiJ(jof a day, and therefore in the thirteenth century was ten days wrong.’—Op. Maj.., vol. i, p. 270 «.]