428 
POPULAR SCIENCE REVIEW 
If it was not the bright nucleus of a comet it must have been a planet. It 
appears, from calculations made by Gaillot, director of the Bureau des Oalculs, 
that the observed place of the stranger agrees fairly with one of the orbits 
assigned by Leverrier to Lescarbault’s Vulcan. If it should turn out that 
the stranger really is Vulcan, this planet travels round the sun in a period 
less than that in which the sun rotates on his axis. Its period is about 24^ 
days, its synodical period about 26 days, its mean distance from the sun 
about 15,000,000 miles. Professor Watson remarks that in superior con- 
junction the star may appear of the first magnitude. But if he could detect 
no departure from the circular form (and he writes " there was no appear- 
ance of elongation such as might be expected if it were a comet ”) the planet 
could not have been far from superior conjunction. Yet Gaillot says “ that 
if the new body were Vulcan, only a very small part of the disc would have 
been illuminated.” The inference seems to be that either Gaillot’s theory of 
the new body must be erroneous, or else Watson’s failure to recognize any 
departure from circularity was inexact to a very remarkable degree. On the 
whole, while the existence of an unknown body close to the sun on July 29 
last seems very clearly made out, the identity of this body and Lescarbault’s 
Vulcan seems very far from being established. 
Magnetic and Electric Action in the Sun’s Atmosphere. — M. Cornu, from 
an investigation of his spectroscopic observations, has arrived at the conclu- 
sion that the dark lines in the solar spectrum indicate the action of an 
absorbing atmosphere similar in its constitution to volatilized meteorites. 
From this' he infers that the enormous mass of the sun’s atmosphere, con- 
taining, like the meteorites, a large proportion of the vapour of iron, exer- 
cises an appreciable action on terrestrial magnetic phenomena, so that the 
diurnal variations of the needle would on this view be due to the direct 
magnetic action of the sun. He argues that, although iron when heated to 
incandescence loses its attraction on the magnet, it has not been proved that 
the attractive force is reduced rigorously to zero, and there may be sufficient 
left to exercise a very appreciable action on the earth. M. Cornu also con- 
siders that the earth, having probably a common origin with the sun, may 
also be largely composed of iron — a supposition which would explain terres- 
trial magnetism. Considering that the solar prominences show a spectrum 
identical, in the relative brightness and sharpness of the lines, with that of 
highly rarefied hydrogen rendered incandescent by the electric discharge, 
M. Cornu thinks it probable that, appearing as they do in the neighbour- 
hood of faculse and spots, they represent masses of gas traversed by induc- 
tion currents in the neighbourhood of magnetic or electric regions in rapid 
motion, and that, as M. Fizeau has already pointed out, they are analogous 
to the terrestrial aurora. The prominences being, on this view, simply due 
to the illumination by induction currents of masses of rarefied gas, their 
rapid extension and sudden disappearance would be explained without having 
recourse to the hypothesis of jets of gas having velocities of hundreds of 
miles in a second. 
Planetary Phenomena fa)' the Quarter. — Neptune will be in opposition to 
the sun on October 31, at 10 p.m. Venus will be in superior conjunction 
with the sun on December 5, 6 p.m. Mercury will be in superior conjunc- 
tion on October 24, at 8 p.m., and at its greatest easterly elongation (20f°) 
on December 8, at 4 p.m. 
