1872. ] Notices of Books. 253 
or terrestrial phenomenon. The extract given by the editor 
from the Report of the Council of the Astronomical Society 
appears to us, we must admit, to be scarcely more satisfactory, 
since it speaks of theories as admissible which could not at the 
time be possibly entertained in the presence of evidence already 
available. Of course after the results of the recent eclipse all 
the doubts thus expressed must be regarded as definitely disposed 
of ; the reality of the corona, even to its utmost visible limits, as 
Fic. 20. 
Gould’s Drawing of the Corona, August 7, 1869. (5h.) 
a solar appendage of wonderful extent and complexity, being now 
admitted by all. But it is worthy of notice in this place how 
feeble had been the evidence on account of which the true theory 
of the corona was so long disputed. The difficulty of delineating 
an object so delicate, and the consequent differences between 
pictures taken by different observers:at different places, and under 
different atmospheric conditions,—changes supposed to have 
been recognised by one and the same observer,—and imagined 
differences between photographic pictures really resembling each 
