41.

About Byzantium the longest day consists of fifteen and a quarter equinoctial hours; the proportion borne by the gnomon to the shadow at the summer solstice, is as 120 to 42, minus one-fifth. These places are distant967 from the middle of Rhodes about 4900 stadia, and 30,300 from the equator. Sailing into the Euxine and advancing 1400 stadia to the north, the longest day is found to consist of fifteen and a half equinoctial hours. These places are equi-distant between the pole and equatorial circle; the arctic circle is at their zenith, the star in the neck of Cassiopeia is within this circle, the star forming the right elbow of Perseus being a little more to the north.