See ee ae 
ee Pe ee, De a ee ee ee eee ee ee 
Researches on Solar Physics. 179 
which the reader is referred. The main object of the present 
article is to place before those American readers of this Journal, 
who may not have access to foreign Journals, such views an 
important geological facts as Profs. Marcou and Capellini ob- 
tained in their field investigations, as well as those of Prof. Heer 
from the study of the fossil plants. 
University of Pennsylvania, Philadelphia, Jan. 8th, 1867. 
Art. XTX.—Researches on Solar Physics ;* by WARREN DE LA 
RUvE, Esq., Pres, R.A.S., BaLrour Stewart, Esq., Superin- 
tendent of the Kew Observatory, and Bensamin Loewy, 
sq., Observer and Computer to the Kew Observatory. 
First Series——On the Nature of Sun-spots. 
2. There are two methods of accom patie this. (1.) Bye 
observations of the sun’s surface may be made by means of a 
* From a memoir printed for private distribution. 
