76 
POPULAE SCIENCE EEYIEW. 
one — and the Editor, by bis additions relating to consonance and dissonance, 
the undulatory theory, and polarisation, gives it a value which of course it 
would not otherwise have had. The treatment of subjects such as terres- 
trial refraction, the calculation of tlie curvature of rays, mirage and its 
explanation, etc. etc., give a particular interest to this volume. The illus- 
trations are, as usual, of a good kind, and number nearly 200. We are 
well pleased with the work as a whole, and we recommend it to our 
readers’ notice as being really worthy of their attention. 
THE OEBS ABOUND US.* 
T HIS is a volume of that popular nature which the English world is now 
almost familiar with from the pen of Mr. II. A. Proctor. It is distinctly 
a work in which the author’s power as a popular scientific wTiter is clearly 
and successfully displayed. He treats his readers to a number of dis- 
courses which originally appeared in some of our literary monthlies, and 
which are as full of interesting knowledge as they are eminently written 
in a style which is most taking to anyone who is not familiar with the 
scientific mode of study. The first paper in the volume strikes us as being 
a particularly good popular essay, and as being one which even the most 
ordinary popular reader must understand if he read it carefully. The 
author seeks to popularise the subject of spectrum analysis in so far as it 
relates to astronomical subjects. To do this he compares it to the various 
sounds that are included in the gamut; and — of course admitting the 
danger of the comparison — he succeeds in making what most persons would 
regard as a very unreadable subject an extremely popular one. Among his 
various chapters, each of which deals with a separate subject, it appears to 
us that his remarks on the Posse Telescope set to new work,” Professor 
Tyndall’s Theory of Comets,” “ What, then, is the Corona ? ” are decidedly 
the best papers in the volume. Still it must not be thought that the other 
contributions are devoid of interest ; for, in our opinion, even the slightest 
of them is not without some particular interest. 
A BUDGET OF PABADOXES.f 
T his is a reprint, with some slight modifications, of a series of contribu- 
tions to the Athenaeum,” on Paradoxes, by the late Professor De 
Morgan. These articles were written with the intention, we are told, of 
enabling persons who were puzzled at the discoveries of the successful few, 
* “ The Orbs Around Us : a series of familiar Essays on the Moon and 
Planets, Meteors and Comets, the Sun and coloured pairs of Suns. By 
Richard A. Proctor, B.A., Hon. Sec. K.A.S. London : I^ongmans. 1872. 
t “A Budget of Paradoxes.” By Augustus De Morgan, F.R.A.S. and 
C.P.S., of Trinity College, Cambridge. London : Longmans, Green, & Co. 
