south and its longitude 50 deg.
west.

For away to the north, on the borders of the _Mare Frigoris_, or Icy Sea, is seen the small _Mare Humboldtianum_, or Humboldt Sea, with a surface of about 10 thousand square miles.

Corresponding to this in the southern hemisphere lies the _Mare Australe_, or South Sea, whose surface, as it extends along the western rim, is rather difficult to calculate.

Finally, right in the centre of the lunar disc, where the equator intersects the first meridian, can be seen _Sinus Medii_, the Central Gulf, the common property therefore of all the hemispheres, the northern and southern, as well as of the eastern and western.
Into these great divisions the surface of our satellite resolved itself before the eyes of Barbican and M'Nicholl.

Adding up the various measurements, they found that the surface of her visible hemisphere was about 7-1/2 millions of square miles, of which about the two thirds comprised the volcanoes, the mountain chains, the rings, the islands--in short, the land portion of the lunar surface; the other third comprised the "seas," the "lakes," the "marshes," the "bays" or "gulfs," and the other divisions usually assigned to water.
To all this deeply interesting information, though the fruit of observation the closest, aided and confirmed by calculation the profoundest, Ardan listened with the utmost indifference.