Reviews—Reynolds’s Geological Atlas. 523 
historical problem, and M. Fouqué adheres to the original explana- 
tion of Mallet. He seems (p. 55) to doubt the real existence of 
vorticose shocks, whereas it is evident, as was shown some years 
ago in this Macazinz (Vol. IX. 1882, pp. 257-265), that such shocks 
in the neighbourhood of the epicentrum are a necessary consequence 
of a large seismic focus, and may be one of the causes of the rotatory 
movement so frequently observed. The cause suggested by Mr. 
Gray is probably, however, that which acts most widely in producing 
this effect. 
It would be difficult, within reasonable limits, to point out the 
many excellences of Prof. Fouqué’s book. But as, in this country, 
it will probably be read chiefly as a supplement to that written by 
our leader in seismology, Prof. Milne, it may be well to note the 
passages that, in this view, will best repay perusal. First and fore- 
most is the admirable treatment of the relations between earthquakes 
and geological structure, the evolutionary aspect of the science 
(pp. 9-80, 189-201). Here we have discussed and summarized the 
work of Suess, Héfer, von Lasaulx, Hoernes and others, as well as 
some of the earlier results obtained by the Swiss Seismological 
Commission. The subject of seismic periodicity is considered with 
great fullness in Chapter x. The useful list of questions drawn up 
by Prof. Heim for aid in the study of earthquakes is reprinted in 
Chapter viii. The velocity of earth-waves occupies a long and 
interesting chapter, and includes an account of the valuable experi- 
ments made by the author in conjunction with M. Lévy. Lastly, 
the second part of the book (pp. 249-326) contains a description of 
a few of the more important earthquakes that have happened between 
1854 and 1887. 
The illustrations, with one or two exceptions, are good; and 
among them may specially be noticed the maps of the Swiss earth- 
quakes of Nov. 1879—Dec. 1880, and of July 22, 1881, the Charles- 
ton earthquake of August 31, 1886, and the Andalusian earthquake 
of Dec. 25, 1884. 
C. Davison. 
V.—Reynotps’s Gronocican Arias or Great Brirarn. Com- 
prising a series of County Maps geologically coloured from 
the best authorities.! Second Edition, 1889. 
Aas book which calls for a new edition, by reason of its intrinsic 
IG value, is worthy of notice. A new edition of the well- 
known Geological Atlas of Great Britain, published by Messrs. 
Reynolds & Sons, 174 Strand, has just been issued. ‘This atlas 
comprises 82 county maps geologically coloured and arranged 
alphabetically, the colours depicting the varied geological features 
of each county are mainly those used on the published maps of 
the Geological Survey. 
Every county is carefully coloured, and the colours numbered 
1 Published by James Reynolds & Sons, 174 Strand, 1889. 
