126 =W. Huggins—Photographing the Solar Corona. 
Art. XIIL—On a Method of Photographing the Solar Corona 
without an Eclipse ;* by WitutAM Huaeatns, D.C.L., LL.D., 
F.R.S. 
PROBLEMS of the highest interest in the physics of our sun 
are connected, doubtless, with the varying forms which the 
coronal light is known to assume, but these would seem to ad- 
mit of solution only on the condition of its being possible to 
study the corona continuously, and so to be able to confront its 
% ? 
which are hidden by the glare of our atmosphere, the progress 
of our knowledge must be very siow, for the corona is visible 
only about eight days in a century, in the aggregate, and then 
only over narrow stripes on the earth’s surface, and but from 
p 
In the years 1866-68 I tried screens of colored glasses and 
other absorptive media, by which I was able to isolate certain 
portions of the spectrum, with the hope of seeing directly, with- 
out the use of the prism, the solar prominences.¢ I was unsuc- 
cessful, for the reason that I was not able by any glasses or 
other media to isolate so very restricted a portion of the spec- 
trum as is represented by a bright line. This cause of unsuit- 
ableness of this method for the prominences which give bright 
lines only, recommends it as very promising for the corona. 
f by screens of colored glass or other absorptive media the 
region of the spectrum between G and H could be isolated, then 
the coronal light which is here very strong would have to con- 
tend only with a similar range of refrangibility of the light scat- 
* Nature, Dec. 29. Communicated in proof for this Journal, by the author. 
+ “The Sun,” p. 239. 
¢ “Monthly Notices,” vol. xxviii, p. 88, and vol, xxix, p. 4. 
