me in full daylight, and without a total eclipse. This method, which
has given such an immense impetus to the study of the sun, was the
outcome of independent and simultaneous investigation on the part of the
French astronomer, the late M. Janssen, and the English astronomer,
Professor (now Sir Norman) Lockyer, a circumstance strangely reminiscent
of the discovery of Neptune. The principles on which the method was
founded seem, however, to have occurred to Dr. (now Sir William) Huggins
some time previously.

The eclipse of December 22, 1870, was total for a little more than two
minutes, and its track passed across the Mediterranean. M. Janssen, of
whom mention has just been made, escaped in a balloon from then besieged
Paris, taking his instruments with him, and made his way to Oran, in
Algeria, in order to observe it; but his expectations were disappointed
by cloudy weather. The expedition sent out from England had the
misfortune to be shipwrecked off the coast of Sicily. But the occasion
was redeemed by a memorable observation made by the American astronomer,
the late Professor Young, which revealed the existence of what is now
known as the "Reversing Layer." This is a shallow layer of gases which
lies immediately beneath the chromosphere. An illustration of the
corona, as it was seen during the above eclipse, will be found on Plate
VII. (A), p. 142.

In the eclipse of December 12, 1871, total across Southern India, the
photographs of the corona obtained by Mr. Davis, assistant to Lord
Lindsay (now the Earl of Crawford), displayed a wealth of detail
hitherto unapproached.

The eclipse of July 29, 1878, total across the western states of North
America, was a remarkable success, and a magnificent view of the corona
was obtained by the well-known American astronomer and physicist, the
late Professor Langley, from the summit of Pike's Peak, Colorado, over
14,000 feet above the level of the sea. The coronal streamers were seen
to extend to a much greater distance at this altitude than at points
less elevated, and the corona itself remained visible during more than
four minutes after the end of totality. It was, however, not entirely a
question of altitude; the coronal streamers were actually very much
longer on this occasion than in most of the eclipses which had
previously been observed.

The eclipse of May 17, 1882, observed in Upper Egypt, is notable from
the fact that, in one of the photographs taken by Dr. Schuste