948 THE SOLAR ECLIPSE. 
It is impossible to establish a complete accordance between the observations 
of the different astronomers, both because no observer has noted all the pro- 
tuberances, and also because, in estimating or graphically representing the 
position-angles, the accidental errors may come out quite large, as is already 
evident from the examples cited. ‘To this may yet be added that on the west 
side of the moon, at the middle of totality, only simgle protuberances appeared ; 
while later, on this side, they extended to long mountain ridges, so as to pre- 
sent a different aspect every moment, rendering an identical reference impos- 
sible. 
The attempts made in Desierto de las Palmas and Rivabellosa to photograph 
the phenomena of the eclipse led to the satisfactory result that not only some 
success is to be obtained, (which, indeed, could scarcely be doubted after the 
attempts made in Kénigsberg in 1851,) but also that the phenomena are much 
more correctly and completely recorded than by direct observation. The posi- 
tion-angles of the protuberances obtained by photographing (very uncertainly, 
indeed, on account of the smallness and want of precision in the images) were 
given by Mr. Aguilar as follows: 
Desierto de las Palmas. | Rivabellosa. 
Pee rOtberanee-a. .o.coces os aCe hes ols ae see See aoe 282 
en U0! < es Oat cara sites Cole ORS cI clint eo etelaiere 57 Oe 
See eae 2... 4 Gis we oh Pelee k es cee 159 154 
MEME CLC teres ccc ie crocs Crake Oiele ane yelnte Sepa e Cones 194 197 
Fa 2 fo oi 8 cic ola mpc SD eR eee ica ee cle oe 231 23 
eo 00-4 n= 2 1 yal epi re A 8 Ny we! Bie 260 265 
0 Cee b) SOAR B AR anh Sega as aaa 4 276 278 
Gite HAOe acs Coie cle oa Cit TEN eal alate Brae 340 346 
The fourth protuberance was observed by Mr. Secchi (pos. 195°) and Mr. 
Aguilar, (pos. 193°;) the fifth by Mr. Secchi, (pos. 231°.)* Also, the long 
mountain ridge 6 occurs in the photographs. Moreover, the photographs show 
a considerable number of protuberances not included in the preceding list, and 
among these even very prominent ones, of which no trace was to be perceived 
by direct observation. 'Vhe explanation of this fact presents many difficulties, 
since. if we say that the light of those protuberances may act chemically with- 
out affecting the retina of the eye, we must not forget that in practice hitherto 
no example of this sort has yet been exhibited. 
The fact that the photographs obtained in Metz by Mr. Goulier, (74,) and 
sent to the Paris Academy, show a sort of corona close to the solar crescent, 
which could not be seen by direct observation, appears to be attributable to 
accidental causes, and certainly should not be considered analogous to the 
above-mentioned phenomenon. 
If we would consider more particularly the questions to be brought to test 
by the solar eclipse of the 18th of July, 1860, we find in the first rank those 
relating to the nature of the protuberances. The manifold investigations to 
which the earlier eclipses gave rise were so far from bringing a definite opinion 
with general acceptance that, even now, those who explained the protuberances 
as phenomena of interference or inflexionj and those who considered them as 
solar clouds, were about equally divided. In the above-mentioned preparatory 
memoirs both hypotheses are defended ; and, in fact, Messrs. Airy (5) and Von 
*Sivgularly, both these protuberances are wanting in the drawing made by Mr. Aguilar 
after the direct observation. 
