Note 13 — THE LEARDO MAP OF THE WORLD 1452 OR 1453

On the basis of certain of the figures given by Leardo for the lengths of the days at about the times of the solstices, I have estimated that this table was worked out for about lat. 42° 45′ N, which is more nearly the latitude of Orvieto than that of Venice (45° 30′). (This calculation was made with the Smithsonian Meteorological Tables, 4th edit. (constituting Smithsonian Misc. Colls., Vol. 69, No. 1), Washington, 1918: Table 87, “Duration of Sunshine at Different Latitudes,” and Table 88, “Declination of the Sun for the Year 1899.” The difference in the declination of the sun for 1452 and 1899 is negligible.) Dom Bévenot writes: “I fancy day lengths were reckoned roughly for degrees. Here in Weingarten about 1490 they used tables drawn up for lat. 45° N, though the place is actually 47° 40′.”