THE ISSUES OF THE LATE ECLIPSE. 
137 
the most important achievements of the whole eclipse opera- 
tions. The American one was taken with a six-inch object-glass 
corrected for actinic rays ; the Syracuse one with a photographic 
copying lens, four inches in diameter, of course mounted equa- 
torially. In the latter there is an extent of corona wider than 
any other photograph has shown, wider even than that in the 
corresponding American photograph. No doubt this extension is 
due to the smallness and consequent brightness of the image, for 
the exposure was only eight seconds, while the American plate 
was exposed a minute and a half.* Taken alone, Mr. Brothers’ 
picture is exceedingly valuable : upon one side, for about 120 
degrees of the moon’s circumference, it shows a spreading of 
the coronal light to two diameters of the moon ; in the south- 
east part there is the conspicuous rift alluded to as shown by 
the drawings made in Spain ; and there are two other less con- 
spicuous rifts, one about 40 degrees (measured on the moon’s 
circumference) upwards towards the east of the great one, and 
the other about 60 degrees away to the south. The bright 
leucosphere is plainly indicated, and a tendency to streaming 
rays not perfectly radial is decidedly perceptible, even in an 
enlarged and therefore depreciated copy. But the great value 
of this picture comes out when it is magnified to equal size and 
compared with the American one taken at Xeres. Then it is 
seen that in the main features, especially the conspicuous rifts, 
the two are almost identical. Slight differences can be made 
■cut in the positions of some rather indefinitely-marked portions 
of the coronal boundary, but on the whole the agreement is 
wonderfully close. Now, when it is remembered that these 
pictures were taken at points on the earth’s surface 1,100 miles 
.apart, and that one was taken in absolute time 45 minutes after 
the other, it is perfectly clear that so much of the corona as is 
common to the two photographs is cosmical and not atmo- 
spheric. This is a great point established. And yet those self- 
drawn portraits of the corona open out wide fields for specula- 
tion. What are we to infer from the wedge-shaped rifts? 
They seem to deny the possibility of the outer corona being 
anything like a cosmical cloud near to the moon, on either side, 
for in that case the moon’s motion should have affected them. 
If they were caused by the shadows of lunar mountains cast 
upon a sub-lunar mist, in accordance with Oudemans’ theory, 
the motion aforesaid ought to have modified them considerably 
* In the American picture there is some appearance of the outer coronal 
light having been cut off as by a diaphragm in the telescope. Structural 
details are reported to exist in the original negative, which, from causes 
that will be obvious to a photographer, are not reproduced in an enlarged 
copy such as that which we have before us. 
