366 De la fue and Celestial Photography. [July, 
being taken during the totality, on which are depicted the luminous 
prominences with a precision as to contour and position impossible 
of attainment by eye observations.” ‘Thus was achieved a most 
important end ; and we have secured a record of some peculiar solar 
energy, or its effects, which will greatly aid us in determining the 
physical condition of the solar mass, and its enveloping gaseous 
spheres. For a full and detailed account of the apparatus used, and 
of the methods adopted, as well as for a graphic description of the 
eclipse itself, we must refer our readers to the Bakerian lecture 
already quoted. 
In that paper the methods used in measuring the photographs 
are also fully set forth, and the results discussed at length. It is 
there shown, by measurement of the positions of the luminous 
prominences in the totality of pictures obtaimed at two epochs, one 
immediately after the disappearance, and the other just before the 
re-appearance of the sun, that the angular change of position of the 
luminous prominences with respect to the moon corresponds to the 
theory of their fixature to the sun ;—That the “flames” change only 
apparently, not really, by the moon’s motion over them—that is, 
as the moon covers one portion and discloses another—and do not 
otherwise undergo any alteration ; so that when the clock, by which 
the telescope was moved, was adjusted to the sun’s motion, the “red 
flames” stood still. Moreover, it is therein shown by a comparison 
of the photographic pictures with the optical observations made by 
Mr. De la Rue at the same time, that luminous prominences 
invisible to the human eye are depicted in the photographs; thus 
pointing out and exemplifying by a new experiment the difference 
which has been frequently shown to exist between the solar, 
chemical, and luminous radiations. 
A curious question arises from the consideration of the chemical 
power evidently possessed by these prominences, be they flames or 
clouds. We never, as we have already stated, under ordinary 
circumstances obtain an impressed image of the sun without finding 
the indications of a protected circle—that is, one which proves a 
paucity of chemical power—surrounding the photographic disc. 
Yet, when the light of the solar disc is interrupted by the body of 
the moon, the radiations proceeding from the edge, or rather, 
perhaps, from beyond it, have a strong photographic power. What 
is the cause of this most remarkable difference? The question can 
only be answered satisfactorily by waiting for the evidence of future 
experiments. Those prominences become visible to the eye during 
an eclipse, because the eye is protected by the moon from the 
intense glare of solar light. ‘They evidently belong to the sun. 
This was yet further proved by a careful examination of the photo- 
graphs of the same eclipse obtained by Padre Secchi. The 
luminous prominences, due allowance bemg made for parallax, were 
e 
