370 Notices of Books. (July, 
and that their fluidity is attributable to a certain extent to the 
presence of interstitial water. The difference of barometric 
pressure is adduced as one cause among others of the variation 
of eruptive activity, since the boiling-point of water, which takes 
such a large share in these phenomena, is in this way changed. 
There appears to be no evidence in favour of greater activity of 
volcanos in former ages than at present, though their action at 
no time has been regular, rhythmical, or capable of being reduced 
to an average. Our author therefore sides rather with the 
Uniformitarians than with the Evolutionists, and he even goes 
so far as to see no geological reason that would point to a gradual 
cooling down of the planet. 
Reports on Observations of the Total Solar Eclipse of December 22, 
1870. Conducted under the Direction of Rear-Admiral B. F. 
Sanps, U.S.N., &c. Washington: Government Printing 
Office. 1871. 
WE may without offence hope that the United States Navy may 
never be worse employed than it was in the case of the expedition 
of which the Report is now before us. The claims of hospitality 
to the scientific men from the other side of the Atlantic, for 
which several of the writers in this volume make grateful 
acknowledgments, we shall ever be willing to liquidate: these 
claims can never be so great that we shall not be anxious to 
repay them with interest. 
In the present volume we have the reports of the observations 
of Professor Simon Newcombe, at Gibraltar; and Professors 
Asaph Hall, Wiliam Harkness, and J. R. Eastman, at Syracuse; 
and a letter from Capt. Tupman, of the Royal Marine Artillery, 
accompanied by sketches. Professor Newcombe made his 
observations from Buena Vista, a point about midway between 
Europa Point and the town of Gibraltar, and about twenty miles 
from the line of central eclipse. He enjoyed a fairly clear sky 
during the period of totality, but was disappointed in the 
brilliancy of the corona. 
Professor Hall was on one of the bastians of the town of 
Syracuse. He paid most attention to the corona, and though, 
as in the former case, previously the clouds had impeded the 
view during totality, he was able to make the required obser- 
vations. An adjoining spot was occupied by Professor Harkness, 
whose observations were principally with the polariscope, and 
with the assistance of Capt. Tupman he also used the spectroscope 
to the corona. Professor Eastman was about forty yards from 
the former party. With the assistance of his wife he intended 
to make observations with a clinometer polariscope (on moon, 
sky, and corona) and photometer; he was, however, unsuccessful 
with the latter. 
