158 

NATURE 
[| Fune 29, 1871 

from the glacial sea, its present contour was more pro- 
minently determined, and it has been subsequently further 
modified and enlarged by the older river and its tributaries. 
There is even some reason for believing that its present 
outflow was not its former one, but that, acording to Mr. 
S. V. Wood, jun. (whose researches are so well known) 
the river probably drained southward into the Weald, being 
barred in by a ridge of lofty land zow cut through by the 
Thames river. 
- The deposits of the ancient river afford memorials 
of considerable interest, for they tell us that along its 
forest-clad margins lived numerous mammalia, most of 
which have become extinct in the British area, although 
some of the genera are now restricted to the Europeo- 
Asiatic continent. Thus we find remains of the rhino- 
ceros, elephant, hippopotamus, bear, and lion entombed 
in the valley deposits, affording a proof that at that period 
or previously England was joined to the Continent, over 
which land these animals probably migrated, so that the 
insular position of England is but of comparatively modern 
date. A further study of these remains yields to us the 
important evidence that in this area there were repre- 
sentatives of a northern and southern fauna,—the com- 
mingling of which, as the reindeer and musk ox with the 
hippopotamus and rhinoceros, may have arisen from the 
Thames area having been on the borders of two distinct 
zoological provinces. While, however, the majority of 
the Mammalia belong to extinct species, the Mollusca 
with which they are associated are, with two or three 
exceptions, still found in Britain; one shell, however, the 
Cyrena fluminalis, is at present restricted to the Nile; 
this assemblage in the old brick-earth deposits of the 
Thames valley indicating a greater tenacity of life in the 
molluscan than in the mammalian fauna. 

WEINHOLDS EXPERIMENTAL PHYSICS 
Vorschule der Experimental phystk. Von Adolf F. Wein- 
hold, Professor an der KGnigl. héheren Gewerbschule 
zu Chemnitz. Erster Theil. (Leipzig, 1871. London: 
Williams and Norgate. Pp. 208.) 
HIS is by far the best school-book of Physics we 
have ever seen. Its leading characteristic will be 
understood by many readers from the statement that it is 
intended to be for Physics what Stéckhardt’s well-known 
“Vorschule der Chemie” is for Chemistry. The author 
endeavours, as far as possible, to bring the reader into 
personal contact with physical experiments and pheno- 
mena. He does this by describing in detail, not only how 
to produce the phenomena and make the experiments of 
which he speaks, but also, in most cases, how to make the 
necessary apparatus with such materials as are to be 
got in almost any country-town. The result is that we 
cannot imagine a boy who possesses, in any degree, what 
is called a “ mechanical turn” reading this book, without 
wanting to set to work at oncetomake experiments for him- 
self. One of the main objects of the book is, in fact, to give 
a definite and useful direction to the “taste for making all 
sorts of things,” which, as the author says, is so common 
amongst boys. With this intention he has made a careful 
choice of such experiments as, “‘ by their pleasing nature, 
are adapted to awaken an interest in physical studies, but 
has avoided, as far as possible, the introduction of mere 


playthings, and has altogether excluded everything like 
conjuring tricks.” With regard to the expenditure re- 
quired for making the experiments described, the author 
estimates it at about fifty thalers (7/ 10s.) or a little more, 
but points out to those who are unwilling or unable to 
incur the gradual outlay of this sum, how much may be 
done for far less, A hammer and pair of pliers, “a small 
vice, a hand-vice, a few files, some sheet brass and wire, 
a spirit-lamp, a stock of glass tubing, and one or two 
retort-stands, suffice for a great deal, and should be pro- 
vided before everything else.” 
We are glad to think that there are nowadays in this 
country a considerable and increasing number of school- 
masters whoare anxious to introduce Experimental Physics 
as a regular part of school work, but who aredeterred partly 
by the expense of the apparatus commonly thought neces- 
sary, and partly from the want of clear and full instructions 
as to howit should be used when they have got it. To any 
such we can do no greater service than to recommend 
them immediately to obtain Prof. Weinhold’s book, and to 
follow implicitly the directions he gives. 
We must not, however, leave it to be supposed that 
this work is simply a collection of practical instructions 
for making apparatus and experiments. Although each 
subject, even in the part now before us (which includes 
the general properties of bodies, statics, dynamics, hydro- 
statics, and hydrodynamics) is discussed from the point 
of view afforded by the particular experiments which it is 
intended that the reader should make for himself, the 
general conclusions to which the results of these experi- 
ments lead are always clearly and carefully pointed out ; 
and a student who would work patiently through the 
book would lay a broad and sound foundation for a more 
special study of Physics, and would certainly know far 
more of the subject than the majority of those who have 
gone through in the ordinary way books of much greater 
pretensions. Above all, he could not fail to acquire one in- 
dispensable qualification for further progress, namely, the 
faculty of thinking about physical phenomena as of things 
which actually exist, and are just as fit subjects for the 
exercise of common sense as any of the facts of everyday 
life. This we consider is in itself no small excellence ; 
for whoever has had any experience in teaching the ele- 
mentary parts of Physics, must have become aware that 
very often the chief result of the @ Arzorz method, adopted 
in nearly all English books on the subject, is to make 
students think that the forces and motions of which 
Natural Philosophers talk are, if not fictions invented on 
purpose to puzzle them, at least so unlike anything that 
is ever met with in common experience, that it is useless 
to try to understand anything about them. In fact we 
believe that, except for students whose previous training 
has accustomed them to recognise the special cases that 
are included under general mathematical expression, the 
majority of English treatises on the fundamental parts of 
Physics are rather a hindrance than a help to a clear 
conception of the ideas they profess to explain. The 
true method of teaching Physics, at least to beginners, 
we believe to be the one adopted in this book, whereby 
the learner is made to acquire an actual personal acquain- 
| tance with all the most important facts of the science, 
through the observations which establish them having 
been brought within the range of his personal experience. 
