THE ECLIPSE OF LAST DECEMBER. 
137 
It may perhaps appear strange to speak of the confirmation of 
an already demonstrated circumstance, but the present is not 
the only occasion in the recent history of eclipses, when ob- 
servers have been invited to demonstrate the demonstrated. We 
may now assume that the important discovery in question will be 
admitted by all. Let us consider its nature. Father Secchi 
had suspected, from the circumstance that the spectrum of the 
extreme edge of the solar disc is continuous, that the atmospheric 
layer whose absorption causes the dark lines of the solar spectrum, 
must lie immediately above the photosphere, and be of relatively 
limited extent. Thus, in full daylight, the detection of this 
atmosphere by the bright lines which must in reality constitute 
its spectrum, is rendered almost impracticable * by the ex- 
tremely minute angle subtended by the apparent breadth of the 
ring it must really present. In total eclipses, however, this 
difficulty is momentarily removed when the moon just conceals 
the sun’s disc, or at the moments of second and third contact. 
The edge of the moon, at the place of contact, acts for the 
moment the part of an analysing instrument, revealing the 
shallow atmosphere but hiding the photosphere. Taking ad- 
vantage of this circumstance, Professor Young, in December 
1870, was able to see the beautiful bright line spectrum of the 
complex atmosphere, hundreds of bright lines replacing the 
solar dark lines so soon as the continuous background of the 
spectrum had disappeared. 
One of the first telegrams received from the observers of the 
recent eclipse announced the confirmation of Professor Young’s 
observations by Colonel Tennant. Captain Maclear, who was 
at Bekul, succeeded also in seeing the bright line spectrum. 
Professor Respighi (who adopted a novel method of observing) 
failed at the second contact, and was but partially successful at 
the third, being in doubt whether what he saw was a spectrum 
of bright lines, or simply a discontinuous spectrum ; but we 
shall presently see that his method of observing, though ad- 
mirably suited for the chief purposes he had in view, was not 
well adapted for the recognition of this particular phenomenon. 
Mr. Mosely at Trincomalee, and Mr. Lockyer at Bekul, did not 
recognise the bright line spectrum — a circumstance not very 
surprising, since the appearance of the lines is little more than 
momentary. It need hardly be said that the positive results 
obtained by other observers can by no means be called in ques- 
tion because in all cases the bright lines were not caught 
sight of. 
It was not expected that any fresh information would be 
* Possibly quite impracticable ; but the question is one depending on the 
telescopic aperture and defining power. 
