SCIENTIFIC SUMMARY. 
303 
that discoveries of importance "will he made before the end of the year, 
respecting the moot question of the solar corona. 
The Sun’s Corona . — In a paper communicated to the Royal Astronomical 
Society (see notices for March) Mr. Proctor treats of the .sun’s corona. He 
remarks that 11 The total eclipse of next December will last so short a time, 
that, if possible, no part of that time should be wasted through a misappre- 
hension of the nature of the phenomena to be dealt with; so that it would 
be a matter to be much regretted that mistaken views should be promul- 
gated, supposing it possible to form just ones.” He then considers the evi- 
dence we have against the theory lately put forward that the corona is a 
terrestrial phenomenon. In the first place, he points out that the moon is 
projected as a dark disc against the bright background of the corona. The 
theory that the corona is a terrestrial phenomenon requires that the corona 
should be a foreground, and not a background, to the moon ; and one may 
reasonably inquire how the moon, which lies beyond the earth’s atmosphere, 
should come to be apparently projected upon the supposed glare of that 
atmosphere. But when the actual position of the moon’s shadow, consi- 
dered with reference to tridimensional space, is taken into account, it appears 
that during the period of total obscuration the atmosphere in the direction 
of the corona is not illuminated at all by the sun’s rays. The whole of the 
atmosphere above the observer’s horizon-plane is in partial shadow: that 
part from which, according to Mr. Lockyer’s theory, the corona’s light 
comes, is in total shadow ; and if there is one atmospheric region of this part 
in total shadow which should appear darker than the rest, it is precisely 
that which corresponds in direction with the brightest part of the corona. 
Mr. Proctor then turns to subsidiary evidence. He remarks that atmo- 
spheric glare must undoubtedly exist before totality, and that if his views 
about the absence of glare after totality are correct (that is, if it is reason- 
able to inquire where the glare is to come from), then we might expect 
certain peculiarities to characterise the real glare which exists before totality. 
One such peculiarity is this, that the glare should cover the moon’s disc 
until a moment or two before totality, and be visible in the act of passing 
off that disc. Now, in Col. Tennant’s first photograph of the eclipse of 
August 1868, this glare is actually seen, the instantaneous slide havings 
been removed (owing to a misunderstood order) a moment before totality 
had commenced. Again, during an annular eclipse the glare ought to be 
seen trenching on the moon’s disc and leaving its central parts darker ; and 
accordingly we find that such a phenomenon has more than once been re- 
cognised. Yet again, the moon’s face ought to be visible by reflected earth- 
light, and more than once the features of the lunar surface have been thus 
seen during a total solar eclipse. Again, if the corona be a solar appendage, 
it should be visible a few seconds before and after totality : in 1860 Pr. 
Secchi saw the corona for 40 seconds after totality, and, in the total 
eclipse of 1733, M. Edstrom observed the radiations of the corona maintain 
an unchanged position as they gradually faded out of view with the increas- 
ing solar light. Mr. Proctor proceeds to adduce evidence in favour of the 
theory that the corona is but the richer portion of some appendage which 
causes the phenomenon of the zodiacal light. 
Weather to be Expected during the Approaching Eclipse. — Lieut. Brown 
