SCIENTIFIC SUMMARY. 
ASTRONOMY. 
f^HE Solar Erominences . — One of the most interesting- discoyeries ever 
effected by astronomers has recently rewarded Mr. J. Norman Lockyer’s 
spectroscopic researches. On a reference to our Summary of Astronomy for 
January 1867 (No, 22), it will be seen that more than two years ago Mr. 
Lockyer applied the spectroscope to the analysis of the solar spots, and that 
with such success as to enable him to refute the views which M. Faye had 
expressed respecting the nature of the spots, and to establish on a sufficiently 
firm and stable basis those which had been held by Messrs. De la Rue, Balfour 
Stewart, and Loewy. In the paper in which these results were presented to 
the Royal Society, Mr. Lockyer suggested the possibility that the spectro- 
scope might be applied to search for the spectra of the prominences. As 
the bright lines due to the burning hydrogen around the star T Coronse 
were rendered visible to our spectroscopists, he held that if the prominences 
are due to any similar cause we ought to be able to detect their bright lines 
by the same means. With the instrument he then made use of, however, 
Mr. Lockyer was unable to detect any trace of the spectra of the red pro- 
minences. Mr. Huggins also, with his 8-inch equatorial and the powerful 
spectroscopic apparatus made use of in his physical researches, could detect 
no sign of the prominences, nor could Mr. Stone with the great equatorial 
of the Greenwich Observatory. An instrument was being prepared for Mr. 
Lockyer, by Mr. Browning, the optician, which was to be specially adapted 
to the search for the spectrum of the prominences. Before this instrument 
had been rendered available, however, news came from India that the true 
nature of the prominences had been detected. These objects, as we men- 
tioned in our last summary, were proved to be gaseous. Accordingly, it 
became clear that there was a possibility of seeing the spectrum by full 
daylight. Let us consider lohy this is so : There is a little difficulty about 
the subject, as will be shown by the fact that at a recent meeting of the 
Astronomical Society, the Astronomer-Royal expressed his inability to see 
why the spectroscope can render the light of the prominence-spectra visible 
in the neighbourhood of the strong solar spectrum. We know that no 
means which have yet been devised have rendered the prominences visible. 
If we darken the sun we blot them out ,* if we hide the body of the sun by 
any artificial means, we still leave the illuminated atmosphere, and this is 
quite sufficient to obliterate the prominences. Now, since the reduction of 
