18 CELESTIAL SPECTROSCOPY. 
tric arc, so that Rowland considers that his experiments show ‘“ very 
little evidence” of the breaking up of the terrestrial elements in the 
sun. 
Stas in a recent paper gives the final results of eleven years of re- 
search on the chemical elements in a state of purity, and on the possi- 
bility of decomposing them by the physical and chemical forces at our 
disposal. His experiments on calcium, strontium, lithium, magnesiun, 
silver, sodium, and thallium, show that these substances retain their 
individuality under all conditions, and are unalterable by any forces 
that we can bring to bear upon them. 
Prof. Rowland looks to the solar lines which are unaccounted for as 
a means of enabling him to discover such new terrestrial elements as 
Still lurk in rare minerals and earths, by confronting their spectra 
directly with that of the sun. He has already resolved yttrium spee- 
troscopically into three components, and actually into two. The com- 
parison of the results of this independent analytical method with the 
remarkable but different conclusions to which M. Lecog de Boisbaudran 
and Mr. Crookes have been led respectively, from spectroscopic obser 
vation of these bodies when glowing under molecular bombardment in 
a vacuum tube, will be awaited with much interest. It is worthy of 
remark that, as our knowledge of the spectrum of hydrogen in its com- 
plete form came to us from the stars, it is now from the sun that chem- 
istry is probably about to be enriched by the discovery of new elements. 
In a discussion in the Bakerian Lecture for 1885, of what we knew 
up to that time of the sun’s corona, [ was led to the conclusion that the 
corona is essentially a phenomenon similar in the cause of its formation 
to the tails of comets—namely, that it consists for the most part prob- 
ably of matter going from the sun under the action of a force, possibly 
electrical, which varies as the surface, and can therefore in the case of 
highly attenuated matter easily master the force of gravity even near 
the sun. Though many of the coronal particles may return to the sun, 
those which form the long rays or streamers do not return; they sepa- 
rate and soon become too diffused to be any longer visible, and may 
well go to furnish the matter of the zodiacal light, which otherwise has 
not received a satisfactory explanation. And further, if such a force 
exist at the sun, the changes of terrestrial magnetism may be due to 
direct electric action, as the earth moves ‘through lines of inductive 
force. 
These conclusions appear to be in accordance broadly with the lines 
along which thought has been directed by the results of subsequent 
eclipses. Prof. Schuster takes an essentially similar view, and suggests 
that there may be a direct electric connection between the sun and the 
planets. He asks further whether the sun may not act like a magnet 
in consequence of its revolution about its axis. Prof. Bigelow has re- 
cently treated the coronal forms by the theory of spherical harmonics, 
on the supposition that we see phenomena similar to those of free elec- 
