304 Proceedings of Societies. 
through the valleys on the moon’s limb, that all parts of the edge could 
produce the same identical figure. 
It would be therefore seen that, besides measuring the increase and 
decrease of luminous prominences in the path of the moon, it was im- 
portant also to ascertain if any prominence changed its angular position 
with respect to the moon’s centre. The Astronomer-Royal stated, that 
-in order to do so he had had certain lines ruled on one face of the reflect- 
ing prism, which was placed in the focus of his telescope, which was a 
refractor four.inches aperture, mounted on a sort of altazimuth stand of 
a very portable kind; this was exhibited to the audience. Mr De la 
Rue had used somewhat similar means, and being very skilful in making 
hand-drawings of heavenly bodies, in which he had great practice, he 
completed two drawings, which were exhibited on the diagrams in con- 
nection with the nicrometer lines he had employed ; one of these draw- 
ings was made towards the commencement, the other towards the end of 
the totality. Now it was perfectly obvious, on looking at these drawings, 
that the prominence and red cloud situated at the top of the sun, and 
nearly at right angles to the path of the moon, had shifted their angular 
position during the period of the eclipse. Dr Bruhn, of Leipsic, who 
went to the east of Spain, not being provided with any means of measur- 
ing the angular position of a protuberance, profited by the circumstance 
that one of the prominences became visible before the totality, and 
remained so for several minutes afterwards, to make measurements of 
the distance of the protuberance from the cusps. Now the position of 
the cusps could be calculated to the utmost degree of accuracy for any 
particular time, and Dr Bruhn found that, if the prominence belonged 
to the moor, the cusp must have shifted 26° from its first position on the 
moon’s limb; but that if it belonged to the sun, the cusp had not shifted 
1° during the time he was observing. This was most conclusive evidence 
that the prominence belonged to the sun. 
The Astronomer-Royal then pointed out other drawings of the promi- 
nences, particularly a very beautiful one by Mr Fearnley, of Sweden, 
which, as far as it went, confirmed Mr De la Rue’s drawings of the pro- 
- minences, He then went on to say, that, in 1851, M. Busch took a 
daguerreotype of the corona and prominences, but it was not a very 
successful attempt. Since that period photography had made great pro- 
gress, and it occurred to Mr De la Rue and others that it would be 
extremely desirable to get photographs of the eclipse. Mr De la Rue 
took with him the Kew photoheliograph, and obtained two large photo- 
graphs of the totality. Father Secchi, of the Collegio Romano, had 
obtained five small photographs, and through the kindness of Sefior 
Aguilar he had obtained photographic copies of them. The photographs 
of Mr De la Rue and Father Secchi, though made at widely different 
localities, agreed very closely. In both, the changes in the angular posi- 
tion of the prominences had been measured, and they agreed entirely 
with the supposition that they were connected with the sun. 
Father Secchi had explained, in striking language, his reason for pre- 
ferring photographs to eye-observations. And he had shown that certain 
observations, on which M. Plantamour had founded an idea that the 
changes of magnitude of the prominences were not explained by the 
moon’s motion, were entirely disproved by the photographs. 
Some British officers stationed on the western coast of America observed 
the totality from Puget Sound, when the sun was only 2° above the hori- 
zon ; and he had received some excellent drawings from Captain Richards 
and Captain Parsons. On comparing the drawings of the prominences 
made on the west coast of America with those made in Spain, he was 
unable to reconcile one with the other,—but there was an interval of two 
