130 3 W. Huggins—Photographing the Solar Corona. 
the same in the eclipse plates as they are in my plates taken 
might be desired. It may be that by a somewhat greater re- 
striction of the range of refrangibility of the light which is 
allowed to reach the plate, a still better result may be obtained. 
Plates might be prepared sensitive to a limited range of 
light, but the rapid falling off of the coronal light about H 
would make it undesirable to endeavor to do without an ab- 
sorptive screen. Lenses properly corrected might be employed, 
but my experience shows that excessive caution would have to 
be taken in respect of absolute cleanness of the surfaces and 
of some other points). There might be some advantage In 
intercepting the direct light of the sun itself by placing an 
opaque disk of the sun’s image upon the front surface of the 
absorptive screen. I regret that the very few occasions on 
which it bas been possible to observe the sun has put it out of 
my power to make further experiments in these and some 
other obvious directions. 
—Dee. 15, 1882.]} 
