TOTAL SOLAE ECLIPSE OF JULY 18, 1860. 
361 
Protuberance. 
Synonym. 
Part measured. 
Distance from position line D towards east, 
m degrees and decimals of a degree. 
A. 
r Cauliflower. | 
Iwheatsheaf. J 
First boxmdary, a * . 
Second boundary, a ' . 
First drawing. 
23-0 
28-0 
Second drawing. 
20-0 
24-5 
Middle .... 
25-5 
22-25 
C. 
Detached cloud. 
First point, c . . . 
58-7 
49-0 
Last point, c' . . . 
69-0 
58-5 
K. 
Mountain peak. 
First point, r' . . . 
347-0 
343-5 
In order to reduce these measures to position angles from the North towards East, it 
is necessary to add to them 2° 59', say 3°, which will give us — 
First drawing. 
Second drawing. 
Apparent angular motion 
in the interval. 
A. 
Middle .... 
28-5 
25-25 
3°25 
C. 
First point, c . 
61-7 
52-0 
9-7 
E. 
First point, r' . 
350-0 
346-5 
3-5 
As I before stated, the positions of A and E, were laid down with great care ; and it 
will be hereafter seen that their deviations from the positions given by measurements 
of the photograph are remarkably small. The measurement of all the details, however, 
do not agree so well, because the same care could not be devoted to the laying down of 
their positions. 
These drawings show that there was a decided angular shifting of the luminous pro- 
minence A, and of others, in reference to the moon’s centre ; and taking into account the 
probable interval between the two drawings, namely two minutes, the amount of angular 
motion of A is a very near approximation to the angular change which must actually 
have occurred. As mentioned above, there is in the drawings an exaggeration of the 
dimensions of the prominences, which renders them unfit for the precise determination 
of the moon’s actual progression in the line of motion during the period of totality ; 
nevertheless they afford excellent evidence that there was, in fact, a covering and an 
uncovering of prominences, which, taken in connexion with the change in the position- 
angle of the protuberance A with reference to the moon’s centre, can only be explained 
on the assumption that these extraordinary appendages belong to the sun, and not to the 
moon. 
Furthermore, it would be quite possible to make out, with considerable although not 
with absolute accuracy, from these drawings, the direction of the moon’s motion, and the 
extent to which the prominences first seen were obscured by the progress of the lunar 
disk, and others uncovered on the opposite side as the moon continued her course. For 
instance, it will be remarked on inspection, that the streak of prominences, almost 1' in 
* The letters refer to the index map, Plate XV. 
