The western hemisphere, dedicated to the ladies, according to Ardan, and therefore naturally more capricious, was remarkable for "seas" of smaller dimensions, but much more numerous. These were principally: _Mare Serenitatis_, the Sea of Serenity, 25 deg. north and 20 deg. west, comprising a surface of about 130 thousand square miles; _Mare Crisium_, the Sea of Crises, a round, well defined, dark depression towards the northwestern edge, 17 deg. north 55 deg. west, embracing a surface of 60 thousand square miles, a regular Caspian Sea in fact, only that the plateau in which it lies buried is surrounded by a girdle of much higher mountains. Then towards the equator, with a latitude of 5 deg. north and a longitude of 25 deg. west, appears _Mare Tranquillitatis_, the Sea of Tranquillity, occupying about 180 thousand square miles. This communicates on the south with _Mare Nectaris_, the Sea of Nectar, embracing an extent of about 42 thousand square miles, with a mean latitude of 15 deg. south and a longitude of 35 deg. west. Southwest from _Mare Tranquillitatis_, lies _Mare Fecunditatis_, the Sea of Fertility, the greatest in this hemisphere, as it occupies an extent of more than 300 thousand square miles, its latitude being 3 deg. 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. In fact, even his French politeness could not suppress two or three decided yawns, which of course the mathematicians were too absorbed to notice.