to the cause, nor recollect that we had now passed
through ten or twelve thousand feet of gross vapour, that blunts and
confuses every ray before it reaches the surface of the earth. We were
amazed at the distinctness of vision, and exclaimed together, 'What a
glorious situation for an observatory! had Empedocles had the eyes of
Galileo, what discoveries must he not have made!' We regretted that
Jupiter was not visible, as I am persuaded we might have discovered some
of his satellites with the naked eye, or at least with a small glass
which I had in my pocket."

Brydone wrote a hundred years ago, but his idea of erecting an
observatory on Mount Etna was only revived last year, when Prof.
Tacchini the Astronomer Royal at Palermo, communicated a paper to the
Accademia Gioenia, entitled "_Della Convenienza ed utilita di erigere
sull' Etna una Stazione Astronomico-Meteorologico_." Tacchini mentions
the extraordinary blueness of the sky as seen from Etna, and the
appearance of the sun, which is "whiter and more tranquil" than when
seen from below. Moreover, the spectroscopic lines are defined with
wonderful distinctness. In the evening at 10 o'clock, Sirius appeared to
rival Venus, the peculiarities of the ring of Saturn were seen far
better than at Palermo; and Venus emitted a light sufficiently powerful
to cast shadows; it also scintillated. When the chromosphere of the sun
was examined the next morning by the spectroscope, the inversion of the
magnesium line, and of the line 1474 was immediately apparent, although
it was impossible to obtain this effect at Palermo. Tacchini proposes
that an observatory should be established at the Casa Inglesi, in
connection with the University of Catania, and that it be provided with
a good six-inch refracting telescope, and with meteorological
instruments. In this observatory, constant observations should be made
from the beginning of June to the end of September, and the telescope
should then be transported to Catania, where a duplicate mounting might
be provided for it, and observations continued for the rest of the year.
There seems to be every probability that this scheme will be carried out
in the course of next year.

During this digression we have been toiling along the slopes of the
_Regione Deserta_ and looking at the sky; at length we reach the _Piano
del Lago_ or Plain of the Lake, so called because a lake produced by the
melting of the snows existed here till 1607, when it