11EVIEWS. 
299 
a genuine and interesting record of observations made by one who not only 
understands but wbo loves the particular line of research he has undertaken. 
Mr. Jewitt has here given us an account, accompanied by nearly five hundred 
capital woodcuts, of the grave-mounds u of the three great divisions of our 
history — the Celtic, the Romano-British, and the Anglo-Saxon.” The 
author’s treatment of his subject has no relation to geological doctrine, and 
has not much to do with Early English history ; it is essentially a matter of 
fact account based on very extensive original investigation. To the general 
reader, it seems to us that the author’s observations on the Celtic mounds will 
prove the most interesting, as they are the least familiar, and the author’s 
excellent sketches of the half-opened graves with the skeletons in situ give 
such an excellent idea of the methods practised,- that, even without the text, 
they form in themselves a very succinct history. The other periods, having 
been less or more treated upon in other essays, are less new to the reader, 
though much that Mr. Jewitt has to say about them is novel. We com- 
mend this work highly ; it is a book sui generis , and both the author and 
publisher have done their parts well. 
THE LAWS OF MAGNETISM.* 
P ROFESSOR TYNDALL’S last great treatise has so recently come 
into our hands, and is so vast a work and deals with such a multitude 
of the most important and least known phenomena of magnetism, that we 
can do no more than give a very brief outline of the nature of its contents. 
In the first place we may state that the book — which is a large octavo, 
including over 350 pages — is, in great measure, the reproduction of the 
papers which the author has contributed to purely scientific journals 
during the last eighteen years. It deals with the great question of the re- 
lation of magnetic force to the external world — animate and inanimate — 
and from these developes those great laws which the painstaking research of 
Faraday first revealed. Hence it has an interest, not only for the physicist, 
who must study it with the closest attention, but also for the general 
reader, and not less for the medical man, who, interested in electro-physio- 
logy, may gather from it something to indicate the origin of the curious 
effects which powerful magnets appear to have upon the human frame. It 
would be quite useless for us to attempt, even in the most popular form, an 
analysis of the author’s opinions — the views of one who has devoted a life- 
time of research to their formation — so we will close our notice with the 
titles of the several sections into which the treatise is divided : — Magneto- 
optic Properties of Crystals and Relation of Magnetism and Diamagnetism 
to Molecular Arrangement; Diamagnetism and Magne-Crystallic Action; 
Polarity of the Diamagnetic Force ; On the Polarity of Bismuth, including 
an Examination of the Magnetic Field ; The Nature of the Force by which 
Bodies are Repelled by the Pole of a Magnet; Further Researches on the 
* u Diamagnetism and Magne-Crystallic Action, including the question of 
Diamagnetic Polarity.” By John Tyndall, LL.D., F.R.S. London: Long- 
mans, 1870. 
