The crater of Etna is at
most little more than a mile across. The crater of _Copernicus_ has a
diameter of at least 50 miles. Within it, the travellers could easily
discover by their glasses an immense number of terraced ridges, probably
landslips, alternating with stratifications resulting from successive
eruptions. Here and there, but particularly in the southern side, they
caught glimpses of shadows of such intense blackness, projected across
the plateau and lying there like pitch spots, that they could not tell
them from yawning chasms of incalculable depth. Outside the crater the
shadows were almost as deep, whilst on the plains all around,
particularly in the west, so many small craters could be detected that
the eye in vain attempted to count them.
"Many circular mountains of this kind," observed Barbican, "can be seen
on the lunar surface, but _Copernicus_, though not one of the greatest,
is one of the most remarkable on account of those diverging streaks of
bright light that you see radiating from its summit. By looking
steadily into its crater, you can see more cones than mortal eye ever
lit on before. They are so numerous as to render the interior plateau
quite rugged, and were formerly so many openings giving vent to fire and
volcanic matter.
Pages:
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211