474 
MR. J. EVERSIIED ON THE SOEAli ECLIPSE OF 1900, MAY 28. 
velocities to the whole mass of mixed gases, and it is difficult to see why these 
shoiild not he projected to ecpial altitudes in the chromosphere, yet most of the 
metals with atomic weights between 20 and 100 stop short at from l"to 2" elevation, 
whilst the elements H, He, Ca, and Ti ascend to 8'' or 10.^' 
Tlie same lagging hehind of the elements of the lower chromosphere occurs, 
however, in the so-called “metallic” and great eruptive prominences.* In these the 
higher parts usually consist solely of H, He, Ca and probably Ti, the other elements 
only appearing at the base or stem of the prominence, or frequently only in the 
surroundiDg chromosphere. In the more violent eruptions, too, the distortions due 
to motion in the line of sight affect chiefly the hydrogen and calcium lines, the lines 
of other elements present in such out1)ursts being usually undisturbed, or but slightly 
affected, showing that these elements, although apparently mixed up with the 
hydrogen, do not share in the motion. 
Although it may he difficult at present to understand the nature of these great 
eruptions, it would seem reasonable to suppose that the entire chromosphere consists 
of miniature eruptive prominences of the same nature as the greater outbursts, the 
base of the eruptions giving the metallic lines of the flash spectrum and the higher 
parts the lines of H, He, Ca and Ti only. 
This conclusion is strengthened when it is remembered that the strongly enhanced 
lines of iron at 5317, 5269, 5018, and 4924 so prominent in the flash, are always the 
first to appear as bright lines in the metallic eruptions, other iron lines, although 
stronger than the above in the Fraunhofer spectrum, being seldom or never seen 
reversed. This is doubtless owing to the relatively high temperature of the gases in 
these eruptions com 2 :)ared with the absorbing gases, and in the lower chromosphere 
the enhanced lines indicate a similar state of things, the highly-heated ascending 
jets giving a high temperature emission spectrum more nearly resembling that of the 
spark than of the arc. 
The Flash Spectriini in High Latitudes. 
It is of interest to compare the images at different points on the limb to determine 
wliether the flash spectrum is the same in all latitudes. The limited distribution of 
the metallic })rominences, which, in the writer’s experience, are only to be found in 
the latitudes of spot formation, would perhaps lead one to anticipate some 
modification of the spectrum in high latitudes. 
At the date of the eclipse (May 28th, 19U0) the sun’s south pole was at position 
angle 164° and very nearly coincident witli the limb. Unfortunately, this point, 
and the region within 10° of it on either side, is occupied by the continuous spectrum 
* No spectroscopic distinction can be made between the metallic eruptions and the more quiescent 
forms of prominence, for the latter, when photographed at an eclipse, exhibit the same metallic lines at 
their bases as the former. 
