352 KANSAS CITY REVIEW OF SCIENCE. 
ASTRONOMY. 
THE CORONA. 
EDGAR L. LARKIN. 
Of late, there seems to have been a reversal in scientific opinion regarding 
the coronal light seen around the Sun when eclipsed. Research made by Amer- 
ican astronomers stationed on Caroline Islands, South Pacific, on the total solar 
eclipse May 6, 1883, led to the change in current beliefs. The discoveries of 
Professors Hasting, Holden and Rockwell appear to decide that the corona in- 
stead of being a solar appendage, is simply a diffraction phenomenon. 
The preliminary report of Prof. Hasting in the Baltimore Sun ; the partial 
report of Prof. Holden made at American Association for the Advancement of 
Science, Minneapolis, at its recent session, and a conversation with Astronomer 
Rockwell, at Minneapolis, fully convinced me that the corona is in no way con- 
nected with the Sun. The difficulties in the way of such conclusion have always 
been formidable, for if the corona is solar, then the pressure on the Sun's surface 
would be far greater than the spectroscope shows to exist. By experimenting 
with Geissler's tubes, it was discovered that difference in pressures of gases 
wrought changes in their spectra. Geissler's tubes are made of glass, and have 
apertures through which they can be filled or emptied by a Sprengel pump. 
Each tube has a platinum wire burned through either end so that when the wires 
are attached to the poles of a battery, electric sparks pass from one wire to the 
other through the length of the tube. Suppose it is desired to watch the changes 
in hydrogen spectra developed by different pressures ; all that is needed is to force 
more hydrogen into the tube when the electric sparks are traversing the space 
between the platinum terminals. 
Then we read in Lockyer's Star-Gazing, p. 414, — " We shall find the color of 
the gas through which the spark passes, varies considerably as we increase the 
pressure of the hydrogen in the tube. The hydrogen at starting is nearly as rare 
as it can be, and if more hydrogen be let in we shall see a change of color from 
greenish white to red, the hydrogen admitted has increased the pressure and the 
•color of th,e spark is entirely changed. It is of a very brilliant red color, the color 
of the prominences round the Sun." 
From this, we see that red appears when pressure on hydrogen is no greater 
than can be resisted by a thin shell of glass ; a pressure about that exerted by the 
atmosphere of the earth. We have proof, then, that hydrogen composing the 
solar protuberances does not exist under abnormal compression, — proof derived 
from color. That is, it is not necessary that hydrogen be subjected to a greater 
