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The Earth
Its Origin, H i s t o r y and Physical Constitution
Harold Jeffreys
(4th edition, 1959, pp. 420+Ni, Cambridge University Press)
All geophysicists will be grateful that Sir Harold Jeffreys has found opportunity
to revise his classic work. Those hitherto unfamiliar with T h Emth will discover
with delight Sir Harold's elegant and powerful command of the English language
and of mathematical exposition. They will join the many readers who have been
convinced by the arguments, amused by the chapter headings, roused by the
polemics, and thrilled by the triumphs of scientific method as the author's story is
unfolded.
Those to whom the earlier editions are familiar will be most concerned to see
what changes have been made in the Fourth Edition compared with the Third.
In plan and paragraph numbering there is almost no alteration, but Sir Harold
has added material from the research of the years 1950-58, including his own, on
travel-times of earthquakes, and on the modified Lomnitz law of creep, with its
implications for studies of the departure of the Earth's mantle from purely elastic
behaviour. There are also new considerations on polar wandering, the Moon's
surface features, and the Earth's thermal history. The bibliography has been
considerably augmented, and includes about 700 references, in general running as
far as 1956.
Readers will not be surprised to find that on the whole Sir Harold continues to
hold, and to defend with vigorous and lively argument, his well-known views on
the constitution of the Earth's crust, mountain formation, continental drift, and
the Earth's thermal history.
It is easier to mention topics omitted than to list all those included. This
book does not discuss the information on geophysical problems which has lately
been derived from nuclear explosions and the motion of artificial satellites, nor
recent work on continental and oceanic structure as deduced from widespread
and accurate observations of surface waves. But in spite of the great range of
modem developments in geophysics, there is still very little which cannot be found
treated with insight in this book. The reader cannot fail to be impressed by the
scope of Sir Harold's enquiries and the extent of his information.
The arguments are close-knit, and the mathematics, never included for its own
sake, is usually advanced and sometimes severe. But the text is so written that
the argument can be understood when the mathematical details are taken for
granted.
The first edition of The Emth was published in 1924. In the second, published in 1929,a great deal of new material was included. The third edition, in
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1950, incorporated the results of rapid advances in all branches of geophysics,
and again differed greatly from its predecessor. But the fourth edition, changed
mainly in details from the third, shows that the accepted body of theory and
experimental data is now large. To that body Jeffreys’s 120 original papers and
books have made a major contribution.
Sir Harold‘s close association with the development of geophysics over
forty-five years has given to his writing, with its flair for highlighting key historical
discoveries, something of the excitement of a first-class detective story. He must
be a dull reader who does not catch from it some of the exhilaration of the intellectual search-and struggle which Sir Harold describes with enthusiasm, and in
which he has engaged with such outstanding success.
E.R.L.
Physics of the Earth’s Interior
Beno Gutenberg
(International Geophysics Series Vol.
I,
pp. 240, Academic Press)
Professor Gutenberg, whose death recently occurred, spent a lifetime studying
the Earth, and as a seismologist was eminently qualified to write a book on the
Earth’s interior. This book makes an admirable start to a new series on geophysics
and should make a good textbook for graduate students.
The study of the Earth’s interior relies most heavily on the results of seismological research but, to a lesser extent, draws on a host of other subjects. In these
days, when the effort expended on geophysical research is so enormous, no one
person can expect to have more than a nodding acquaintance with a few of these
fields. Hence, there arises the need for a book which will contain all the important
information from a variety of subjects and which supplies enough references to
make the consultation of the original papers a relatively easy matter. In these
respects, this book is very good. It is, generally speaking, well up to date with
references to papers published during 1959. Perhaps it was expecting too much to
see references to the new data on the figure of the Earth obtained from Earth
satellites, but such subjects as radiative heat transfer, phase changes and the
palaeomagnetic data collected during the past few years are discussed.
A consistent feature of the book is the emphasis given to the physical problems involved, with mathematics reduced to the minimum necessary for exposition. Separate chapters are devoted to the crust, mantle and core and other chapters are concerned with the physical conditions and rheological properties of the
various regions. Where the author feels less than expert, he is content to quote,
sometimes with a healthy scepticism, extracts from original papers. This attitude
is particularly evident in the first few pages of the book on methods of investigation and the accuracy of results. He draws attention to the dangers of using the
results of investigations without a proper appreciation of their limitations. So
often have the “facts” about the Earth’s interior been shown to be without foundation. For this section alone, the book deserves a place on the shelves of geophysicists.
D.C.T.