KEVIEWS. 
83 
caverns of Ireland, some of which — that, for example, at Dunmore, where 
so many human beings were destroyed by the cruelty of an English officer in 
days gone by — are vastly larger than any of the English caverns. But if we 
overlook this we certainly must admire the manner in which he has given 
and illustrated his account of the caves. More than 190 woodcuts are dis- 
tributed over the book, and lend a considerable interest to what otherwise 
might prove to the general reader somewhat dry matter. The information 
in the appendix will be useful to intending cave-explorers, for it explains the 
various instruments that are of use to the cavern-hunter. More particularly 
do we think the statements on the subject of cave-rafts extremely valuable. 
The facts, too, as to the method to be pursued in the exploration of newly- 
found caverns we think very useful. One of the chapters of the work 
consists of a report of Mr. Busk’s paper on the human remains from the 
cavern at Perthi-Chwareu, and this is a most instructive communication, 
from the very careful manner in which the various measurements have been 
recorded. Altogether we must wish the book every success, for it is a very 
good summary of the labours that have been achieved by one of the most 
laborious and highly qualified of the labourers. 
T HE author of the well-known treatise on “ The Wave Theory of Light,” 
Dr. Lloyd, of Trinity College, Dublin, has now produced as im- 
portant a treatise on the subject of general and terrestrial magnetism. It 
would, of course, be entirely out of our province to criticise such a work, 
which comes from the very first authority on this subject. We have, how- 
ever, great pleasure in announcing the book, and stating that mathematical 
readers will find it discusses fully the laws of this complex branch of physics. 
THE MENTAL AND SOCIAL CONDITION OF SAVAGES. t 
SSTJBEDLY this was a difficult task to take in hand, for it involved, 
besides a wondrous amount of reading, a keen discrimination between 
what was reliable and untrustworthy, and eventually a very close power of 
reasoning to place the facts attained by the system of study in their proper 
order. In fact, the drawing up of such conclusions as Sir John Lubbock’s 
was a task which we are sure must have taken him years to accomplish. 
And however we may object to some of the determinations he has drawn, we 
must bow to the natural honesty of purpose that appears displayed through- 
* “A Treatise on Magnetism, General and Terrestrial.” By Humphrey 
Lloyd, D.D., D.C.L., Provost of Trinity College, Dublin, formerly Professor 
of Natural Philosophy in the University. London : Longmans, 1874. 
t “ The Origin of Civilisation and the Primitive Condition of Man.” By 
Sir John Lubbock, Bart., M.P., F.R.S. 3rd edition. London : Longmans, 
ON MAGNETISM.* 
1875. 
G 2 
