TOTAL SOLAE ECLIPSE OE JULY 18, 1860. 
403 
their action undisturbed during the remainder of the time of exposure : this picture is 
the one which includes those images of the several prominences depicted furthest to the 
right in each case, Plate IX. fig. 2. During the exposure of the plate in its third period 
there was a slight irregularity in the motion of the driving-apparatus, which to a very 
small extent enlarged the prominences in the direction of right ascension. 
In making a representation of the state of the phenomena at the end of totality, it 
was only necessary to paint out the two impressions of each of the several prominences 
belonging to the two other periods depicted on the photograph, and to correct the slight 
exaggeration caused by the irregularity of the driving-apparatus. In this way was pro- 
duced the touched photograph y, represented in Plate XII., which faithfully shows the 
state of matters about a second, or less, before the reappearance of the sun. It has 
been possible to make out, from photograph 26, three corrected pictures, showing the 
appearance of the prominences at three difierent epochs of that period of totality during 
which it was in the heliograph ; but only one of the resulting pictures has been engraved, 
namely, that shown in Plate XII. 
The irregularity of many of the protuberances on the concave side adjacent to the 
lunar disk is very striking, and appeared to me, while observing the eclipse with the 
achromatic, to be greater than could be attributable to the indentation which would be 
caused by any amount of irregularity on the lunar periphery. The extent of this irre- 
gularity could be readily estimated during the other phases of the eclipse with the tele- 
scope, and is also depicted clearly on the several photographs, which afibrd a permanent 
record of the moon’s profile. In Plate XVI., which was produced by etching an enlarged 
positive copy of photograph 22 and electrotyping from it, is shown the profile of the 
moon’s limb between the position-angles 44°'5 and 191°; in Plate XVII., produced in a 
like manner from photograph 28, the moon’s profile is depicted between the position- 
angles 228° and 9° ; altogether the plates exhibit 287° of the moon’s outline, with which 
the concave edge of the luminous prominences shown in Plates XIII. and XIV. may be 
compared. As the moon moved onwards, the great amount of indentation of the con- 
cave side of the protuberances appeared to me to become less on the eastern side and 
greater on the western side. Some of the ii’regularity on the concave side is undoubtedly 
due to the periphery of the lunar disk, but all of it cannot be so accounted for. We may 
assume that some prominences are not in absolute contact with the sun’s photosphere, 
but, on the contrary, are supported at a distance from it, as in the case of the float- 
ing cloud D. Notably, in that part of the prominence G between the position-angles 
112° and 124° the irregularity of the concave boundary cannot be accounted for by the 
form of the moon’s limb ; on the other hand, in support of the position that in certain 
cases the irregularity must be due to the profile of the moon’s disk, we have good 
evidence in the second totality-photograph, Plate IX. fig. 2, where part of the luminous 
prominence Q is depicted at two epochs, namely, just as it became visible, and at the 
end of totality. It will be seen that the part ^ has the same amount of indentation 
at both epochs. In most cases the irregularity of the contour of the prominences 
