28 
NATURE 
| May 14, 1885 
the cable ; further, the construction of telegraphic signal 
apparatuses able to utilise the first weak beginnings of the 
current arriving at the other end of the cable. These 
ultimately led to the invention of the siphon-recorder—a 
writing apparatus in which the tube containing the ink 
does not come into immediate contact with the strips of 
paper on which it has to write, and is therefore not 
hindered by friction from moving even under the least 
electro-magnetic impulse. By electric charges it is 
brought about that the ink spurts over the paper ina 
series of fine points. 
The conclusion of the second volume is formed by the 
Bakerian Lecture for 1856, which gathers up the results 
of the author’s investigations into the qualities of metals 
as displayed under the conduction of electric currents, 
and under magnetisation, and the changes they undergo 
in consequence of mechanical, thermal, and magnetic 
influences. 
Let us hope for an early continuation of this interesting 
collection. There are still nearly thirty years of scientific 
activity on the part of the author to be accounted for. 
When we think of that we cannot fail to be astonished at 
the fruitfulness and unweariedness of his intellect. 
HERMANN L., F. HELMHOLTZ 
OUR BOOK SHELF 
Paradise Found. The Cradle of the Human Race at the 
North Pole. A Study of the Prehistoric World. By 
William F. Warren, S.T.D., LL.D., President of Boston 
University, &c. (London: Sampson Low and Co.) 
It has come to be an understood thing that when geolo- 
gists or biologists propound theories as to past stages of 
life on the earth, and these theories attain to a certain 
popularity, some theologian shall twist the words of the 
Book of Genesis into a new interpretation, to show that 
this was what the inspired author meant all the time. A 
fresh musician has set Moses to dance to a new scientific 
tune. Since the publication of well-known modern views 
as to the diffusion of plants and animals from the Polar 
Region, it was to be expected that we should have a book 
proving that man was created in an Arctic Paradise with 
the Tree of Life at the North Pole; and here the book is. 
Other ancient cosmologies, such as the Greek and Indian, 
are made to bear their not always willing testimony. 
Those who take up the book should notice that the com- 
mendatory letters published from Professors Sayce, Tiele, 
and Whitney do not at all imply that these eminent 
scholars countenance the Polar Paradise doctrine. The 
President of Boston University seems to have sent them 
a paper some years ago on “Ancient Cosmology and 
Mythical Geography,” their acknowledgments of which 
they are now perhaps hardly delighted to find figuring as 
certificates in a “ Paradise Found.” 
Epping Forest. By Edward North Buxton, Verderer. 
(London: Stanford, 1885.) 
THE public generally, and especially the people of 
London, and those who take some interest in natural 
history, are to be congratulated on the acquisition of so 
charmingly complete a little itinerary of Epping Forest 
as that now issued in a cheaper form by one of the 
Committee of Conservators, who is a resident on the 
borders, and an enthusiast as to the attractions of the 
Forest. It is, as thé author observes in his preface, 
“hardly a desirable dtate of things” that so small a 
percentage of the summer visitors to the Forest “ever 
venture far from the point at which they are set down by 
train or vehicle;” and, with the choice of a score of 
beautiful walks, described in Mr. Buxton’s book, and the 
guidance of his six carefully prepared maps, five of which 
are on the scale of three inches to the mile, there is no 
longer any reason for their not venturing into those 
depths of the Forest in which its chief beauties are to be 
seen. The chapter on the history of the Forest which 
the author has wisely prefixed to the itinerary, that 
visitors may be reminded of the events which secured 
this magnificent playground for their enjoyment, is 
most complete, though it is to be regretted that the late 
City Solicitor, Sir Thomas Nelson, is not mentioned dy 
name on p.22. The practical character of the book may 
be gauged from the inclusion of railway time-tables, the 
fact that the distinctive letters of each route have been 
cut on trees at some points, and from such suggestions 
as that an east wind is, in Epping Forest, the best for 
views, because not smoke-laden. Personal experience 
has convinced the present writer of the skill with which 
the routes have been selected; the “objects of interest 
within and around the Forest,” and their historical asso- 
ciations, are fully described and illustrated by some 
excellent drawings, the latter by Mr. Heywood Sumner ; 
but what must render the work peculiarly gratifying to all 
lovers of nature, is the ample space—more than half the 
volume—devoted to the fauna and flora of the Forest. 
The mammals, reptiles, birds; the chief moths and 
butterflies ; the trees, flowering plants, ferns, fungi, and 
mosses, are all enumerated, with general, ze. not too 
specific, localities; and the notes on the mammals and 
birds will be of interest to naturalists in other districts. 
Such lists can, fortunately, never be complete ; insects 
marked as “rare” are notoriously liable at any time to 
prove common: even since the publication of this work 
evidence has been produced suggesting the addition of 
Sparganium neglectum to the list of flowers, and each 
year’s cryptogamic meeting of the Essex Field Club has 
as yet added several species to the catalogues of the 
lower plants. There may yet be room for a more pre- 
tentious monograph of Epping Forest, and, of course, 
from the naturalist’s stand-point, so rich a collecting- 
ground affords material for a library of expository litera- 
ture—the freshwater alge, for example, call for recogni- 
tion ;—but, for its purpose, the present work could hardly 
have been executed in a manner more creditable both to 
author and publisher. G. S. BOULGER 
Traité de Minéralogie appliquée aux Arts, a [ Industrie, 
au Commerce et & V Agriculture, &c. Par Raoul 
Jagnaux. Avec 468 figures dans le texte. (Paris: 
Octave Doin, Editeur, 1885.) 
THIS work of 883 pages, as is stated in a title-page of 
corresponding length, is intended for the use of French 
students in their preparation for a degree in the subjects 
of engineering, chemistry, metallurgy, &c. We do not 
think that in its purely scientific contents it is likely to be 
of advantage to English students. The first part, devoted 
to the subject of crystallography, is rather incomplete and 
unsatisfactory, even if regard be had to the main purpose 
of the work. As usual, in the figure of Wollaston’s 
goniometer the crystal is represented as adjusted in a way 
that every. practical student is immediately taught to° 
avoid. Nor will the chemical formule meet with the. 
favour of English students: though the atomic weights of 
oxygen and silicon are given as 16 and 28 respectively, 
silica appears throughout as SiOg, water is still HO, while 
to nitre is assigned the formula KO.AzO;. Further, the 
ordinary symbols for the atoms are occasionally, as in the’ 
forty-nine formule of pp. 423-5, used to signify equivalent 
proportions of the oxides; olivine, for instance, being 
given as (Mg.fe)Si. The classification is likewise 
ancient ; in the description of the species alum stone 
immediately follows the oriental chrysolite, a precious. 
stone, merely because both substances contain alumina. 
In its explanation of the uses which have been discovered 
