THE SOLAR ECLIPSE. 253 
Mr. Goulier (74) brings out in a short notice the circumstance that, in the 
photographs obtained by Mr. Lamey in Metz,.the solar crescent appears sur- 
rounded on all sides by a bright light, of which the direct observations have 
shown no trace. 
The results of Mr. Chacornac, (24,) as well as the apparatus used by him, are 
materially different from the rest. The telescope employed, made by Foucault, 
had a silvered mirror of 0.4 metre (15 Paris inches) [aperture,| and was mounted 
equatorially. The investigation related exclusively to the protuberance d, whose 
position he gives as 50° (30°?) eastward from the north point. While other 
observers compared the protuberance to mountain-tops, mountain-chains, or to 
clouds, Mr. Chacornac declares this comparison wholly inaccurate, and finds in 
the appearance great similarity to numerous gas-flames, or, better yet, to 
a burning pile of straw, or of loose combustible material, on which a current of 
air is acting in such a manner as to bend the many flames into different diree- 
tions. The protuberance consisted of two separate parts: a larger part, where 
it seemed as though the burning had just commenced; and a smaller, where 
apparently the fire had already penetrated through the material, and the burning 
was quietly going on. From the circumstance that some parts appeared very 
distinct, while others seemed to be in a manner wrapped in cloud, we shouid 
infer, says Mr. Chacornac, that some were nearer, and others at a greater dis- 
tance, an idea which Mr. Secchi has also brought forward. Although Mr. 
Chacornac directed his especial attention to only one point, he neveriheless 
swept repeatedly with his telescope over the whole circumference of the moon, 
and so had opportunity to convince himself that all the protuberances presented 
a similar aspect. It is known that Mr. Arago considered the luminous envelope 
of the sun as burning gas, and Mr. Chacornac seems to have had this idea in 
his mind while describing the protuberances. 
_ The different memoirs of Mr. Secehi (60) (61) (62) are of especial interest, 
partly on aécount of the observations which he himself made, and partly by 
reason of the connexion into which he has brought his own observations with 
those of others. He considers the protuberances as portions of the luminous 
"envelope of clouds by which the sun is surrounded, and holds accordingly that 
the solar atmosphere is less extended in the polar regions than toward the 
equator, and that also the agitation of the atmosphere is less at the poles. His 
remark (not fully carried out in all respects) that the photographs obtained by 
himself and Mr. de la Rue are identical is especially noteworthy, as also his 
explanation of the circumstance that protuberances appear in the photographs 
which could not be perceived by direct observation with the telescope. The 
changes of solar heat during the progress of the eclipse were determined by 
Mr. Secchi by means of a thermo-multiplier of Melloni; also magnetic and me- 
teorologic observations were noted down. 
Mr. Prazmowski (51) gave himself to the problem of investigating the polar- 
ization of the corona and of the protuberances, for which purpose he had 
constructed two different instruments. The first, consisting of a telescope mag- 
nifying 22 times, with a quartz plate in the focus, and a Nicol’s prism between 
the first and second eye-lens, showed a strong polarization of the light of the 
corona in which the polarizing plane was perpendicular to the moon’s limb—a 
result which entirely agrees with previous determinations, and with the above- 
mentioned observation of Mr. Seechi. The second instrument, a telescope of 
the same kind as the preceding, but with double the power, had a scale of quartz 
between the first and second lenses, and before the eye-piece a double-refracting 
prism, with a small refracting angle, so that the two images of a protuberance 
appeared near together, (the distance was only 14 minute,) while the two images 
of the corona projected themselves upon each other, and formed a white ground. 
In this way it became)possible to decide the hitherto unsettled question respect- 
ing the polarization of the protuberances by ascertaining that their light is not 
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