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the calcium lines MH and K, was first described by DEsLANDRES in 
1894, then by Jewett in 1896, and has recently been investigated 
very carefully on Mount Wilson by CrarLes B. Sr. JonN *), and at 
Meudon by DesLANDRES*). The main character of these phenomena 
is, that in the spectrum cf the central parts of the solar disk the 
narrow dark lines H, and K, are displaced toward the red, the 
wider, bright lines 7, and K, toward the violet; that these displace- 
ments decrease as we approach the limb, and that, on the other 
hand, the width of those lines increases from the centre to the limb. 
For further particulars we refer to the paper by Sr. JOHN. 
The peculiarities of the phenomenon cannot possibly be explained 
when pressure or magnetic forces are supposed to be the effective 
cause. St. Jonn, who takes no notice of anomalous dispersion as a 
possible cause, is therefore so absolutely convinced of the radial- 
motion nature of the phenomenon (and so are DESLANDRES and JEWELL), 
that he describes the results of his excellent observations under the 
title: “The general circulation of the mean- and high-level calcium 
vapor in tbe solar atmosphere”. 
We are going to show in the following pages, however, that all 
of the properties of the lines M and K, described by DksLANDREs 
and Sr. Jorn, can be interpreted as consequences of anomalous 
dispersion. Thus, fortunately, one is released from the necessity of 
assuming, that in the solar atmosphere two opposite vertical currents 
of calcium vapour are continually kept up, meeting or- perhaps 
passing or penetrating each other with velocities 30 or 60 times 
greater than the velocity of the most violent terrestrial blasts — 
and, marvellously, leaving the hydrogen-and the other gases of the 
chromosphere unaffected! The explanation on the basis of anomalous 
dispersion does not involve such difficult physical notions, and offers 
the advantage, that it easily fits a theory, already connecting a great 
many other phenomena. 
§ 3. The influence of anomalous scattering on the distribution of light. 
The light coming from the lower strata of the sun, and having 
to traverse an extensive absorbing atmosphere, loses intensity not 
only by absorption, but also by scattering. It is true that radiant 
energy, when scattered, only alters its direction of propagation, not 
its nature (whereas, when absorbed, it suffers a change); so the 
scattered energy must finally quit the celestial body in the original 
form. But because part of it always returns to the source, we may 
1) Cuartes KE. Sr. Jonny, Astrophysical Journal, 32, 86—82, (1910). 
2) H. Destanpres, C. R. 152, 233 —259, (1911). 
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