SCIENTIFIC SUMMARY. 
81 
too, has nothing in common with the displacement of floating bodies, and 
the phenomena of segmentation are hardly explained. The scoriae (if such 
there were) would doubtless be formed in the hottest regions ; but, on the 
contrary, they appear in the zones nearest the equator, never at the poles. 
The spots do not appear beyond the 3-5th degree of latitude, while the pro- 
tuberances (supposed to be produced by them) appear as far as the 70th. 
Lastly, consider the long and constant solar radiation. The sun, being 
simply a liquefied mass, would have been long since encrusted. If the con- 
ductibility of liquids and solids is so small that these scoriae resist the heat 
of the liquids for days, weeks, and even whole months, how are we to 
explain the enormous radiation of 1,200,000,000 calories per square metre of 
surface daily ? A state of fluidity nearly gaseous is necessary to allow the 
play of ascending and descending currents to bring heat up from the depths 
of the solar mass and supply the superficial radiation during millions of 
years, and to allow of the progressive contraction of the greater portion of 
the mass repairing, in calories, a part of the secular loss. M. Faye considers 
that the circulation of solar hydrogen arises from a more general phenomenon 
than that supposed by M. Zollner, viz. the vortical movements (with 
vertical axes) produced in the photosphere by its own special mode of 
rotation ; and then radiation is connected with a still more general pheno- 
menon, the mode of alimentation of the photosphere. 
A possible Lunar Atmosphere. — Mr. E. P. Neison has a paper in the last, 
number of the “ Monthly Notices,” in which, after going into the subject, 
with tolerable minuteness, he says that it remains to refer to the objections 
and these we give, allowing the reader to examine the paper itself for the • 
arguments in favour of this view. He states that the objections, with one 
or two exceptions, are all directed against an atmosphere usually as dense,, 
or even denser than our own ; they are valueless as directed against one only 
four-hundredths of this density. The phenomenon referred to by Mr. Proctor, 
in his work on the Moon, as preventing the occupation of a star, could only arise/ 
from a lunar atmosphere much greater than our own, even were it not pre- 
vented from the rays from the Moon after refraction being divergent and not 
Convergent, as he assumes in his illustration. It will also be apparent that 
for the density of the supposed atmosphere, no distortion of a star before 
occupation could possibly occur ; and the same applies to the occupation of 
a planet such as Jupiter or Saturn ; the maximum effect would be to increase 
the size of the planet by about one-thousandth, but in no case distort it. 
Dr. Huggins’ observation (“ Monthly Notices,” vol. xxv. p. 60) is evidently 
by no means delicate enough to detect the very slight effect capable of being 
exerted by an atmosphere of the density supposed. The effect of a lunar 
atmosphere upon an eclipse of the Sun would, if of the density assumed, be 
sensibly the same as a diminution of the semi-diameter by about one second,, 
or would be lost in the effects of irradiation. Finally, it can hardly be 
seriously urged that it could materially interfere with the observation of the 
reversal of the dark lines in the solar spectrum, considering the smallness of 
the horizontal refraction, and the extremely minute amount of scattering of 
the solar rays the supposed atmosphere could effect. No known objection 
yet raised appears to limit a possible lunar atmosphere more than the differ- 
ence between the occupation and telescopic semi-diameter. The real 
YOL. XIII. — NO. L. Gr 
