REVIEWS. 
189 
by a woodcut. The author says, 11 The blowpipe is a tube bent at right 
angles, and drawn to a point at one end. Through the fine opening of the 
pipe, air is forced by the mouth or bellows while the pipe is in the centre 
of the flame.” Now we should like to know what idea a student would 
gather from such an account P We also observe that the author is fond of 
a popular ” descriptions, which, as in the case of hairs, which he says, “ are 
tubes,” are generally incorrect. The want of illustrations is an obvious 
defect in a book like the present, intended exclusively for the young. Still 
we must not be too severe, for the book is, on the whole, a good one. 
New Theory of the Figure of the Earth , considered as a Solid of Revolution ] 
founded on the direct employment of the centrifugal force, instead of the 
common principles of attraction and variable density, by W. Ogilby, M.A., 
F.G.S. London : Longmans, 1872. — Leaders must really judge for them- 
selves of the 'value of such a work as the present. For ourselves, we 
prefer to conceal our opinion of the book, as it would not be complimentary 
to the author were we to express really what we think about it. Mr. 
Ogilby says, that u the principles of the method here proposed for treating 
the problem of the figure of the earth are extremely simple. I make no 
hypothesis of any description, nor require any other data than those which 
are furnished by observation and experience. Starting from the admitted 
phenomenon that the earth is a heterogeneous solid whose mean density, 
magnitude, and periodic rotation are known quantities, I thence proceed to 
examine the action of the centrifugal force in producing its present figure, 
determining the law of gravity at its surface, the variation of curvature, 
the length of the terrestrial axis, and the change of local ellipticity at every 
point on the surface ; with other phenomena relating to its present and 
original structure and condition. This mode of treatment furnishes definite 
results without doctoring the process either by the introduction of extem- 
porised assumptions, or the rejection of unmanageable quantities.” 
Reports on Observations of the Total Solar Eclipse of December 22, 1870, 
conducted under the direction of Rear-Admiral B. F. Sands, U.S.N. Wash- 
ington Government Printing Office, 1871. — Of very different material to the 
above-mentioned volume is the able series of essays contained in the work 
now under notice. It is the combined series of reports of the different 
American astronomers who witnessed the eclipse of December 1870. First 
is the report of the editor of the volume ; then those of Professor Simon 
Newcomb, on observations at Gibraltar ; of Professor Asaph Hall, of Pro- 
fessor William Harkness, and of Professor J. T. R. Eastman, of their several 
observations at Syracuse, in Sicily. The volume is accompanied by a couple 
of excellent coloured plates of the solar eclipse one by Captain Tupman, 
of the entire phase of the eclipse, and the second by Professor J. R. East- 
man, of the corona and protuberances on the western limb of the sun, 
near the end of the total phase of the same eclipse. These accounts are 
all capital and very full, some being possessed of details absent from 
the others, some have descriptions of the minute details of the spectrum 
examination, others having to do more with the meterology of the obser- 
vations. All are most exact and comprehensive, and tout entier , they form 
a volume which no modern astronomer should be without. 
