Supplement to “ Nature,’ March 14, 1907 Vv 
that usually results from two years of the most con- 
scientious teaching of inorganic chemistry, no matter 
how, by whom, or to whom the teaching be adminis- 
tered. The bool is condensed, but it is not dull; 
there is, in fact, a sort of grip about it which is 
decidedly sustaining. Many subjects of difficulty, such 
as the complex cyanides and the amines, are treated 
with much clearness and perspicuity, and most new 
things in inorganic chemistry are well elucidated. It 
is really a work on systematic chemistry, a study of 
chemical compounds per se, detached from all the arts 
of man, a sort of comparative anatomy based on the 
periodic law. Judged from this point of view, and 
not as a work that purports to contain all that a 
degree student should know of inorganic chemistry, it 
seems to the present writer as good as any work that 
has been written with the same object, and a great 
deal better than most of them. 
Very few mistakes have been noticed in reading 
the book, but the expression (p. 8), ‘‘ the modified 
form of Gay-Lussac’s law is Avogadro’s law,’’ would 
shock the author of the first book under notice, and 
it is certainly not felicitous. On p. 44 the hydrides 
of sodium and potassium are (in view of Moissan’s 
work) unfairly denied the character of definite com- 
pounds; and on p. 202 nitrogen trioxide is said to 
dissociate completely into nitric oxide and nitrogen 
peroxide on evaporating. The authors propose and 
use the terms basigenic and oxygenic respectively for 
base-producing and acid-producing, and there seems 
to be some need for such words; it is certainly 
confusing to speak of the basic properties of oxygen 
and the basic properties of caustic soda. 
ARTHUR SMITHELLS. 
GEOGRAPHY FOR SCHOOLS. 
A Progressive Course of Comparative Geography on 
the Concentric System. By P. H. L’Estrange. 
Pp. xii+148. (London: Geo. Philip and Son, 
Ltd., 1906.) Price 6s. net- 
Philips’ Progressive Atlas of Comparative Geography. 
Edited by P. H. L’Estrange. Pp. 148. (London: 
Geo. Philip and Son, Ltd., n.d.) Price 3s. 6d. 
net. 
Stanford’s Octavo Atlas of Modern Geography. Third 
edition. Pp. 104+50 maps. (London: Edward 
Stanford, 1906.) Price 25s. 
A Pye very title of Mr. L’Estrange’s book expresses 
an admirable idea. The graduation of geo- 
graphical teaching in such a way as to adapt the 
matter to boys and girls of different ages, and yet 
to make it educational at every stage, and hence to 
present at successive stages tasks of gradually 
advancing difficulty, is admittedly one of the hardest 
and at the same time one of the most important 
problems which the teacher has to face. In his 
attempt to accomplish this task Mr. L’Estrange has 
produced a work on which a very great amount of 
thought and pains have been bestowed, with such a 
wealth of instructive maps extremely useful for 
teaching purposes, and of equally instructive pictorial 
illustrations, and with a text possessing so many 
NO. 1950, VOL. 75} 
valuable features, that it may be unhesitatingly and 
cordially recommended to every teacher of geography. 
It is to be regretted, however, that one cannot feel 
the same confidence in recommending the bool for 
the use of the pupils. Notwithstanding all that Mr. 
L’Estrange has succeeded in doing, notwithstanding 
the fact that he has made important contributions to 
the solution of the problem that he has set himself, 
it can scarcely be admitted that he has been quite 
successful in so mastering the store of information 
he has amassed as to lead the learner securely on- 
wards in the manner he has designed. This results 
partly, it would seem, from the fact that he has 
never formed any clear conception of the function of 
geography as distinguished from geology. He gives 
us no definition of the subject, but opens at once 
with an account of the structure of the earth’s crust 
such as is given by the geologist. The greater part 
of this account is, no doubt, also of geographical 
interest, but if Mr. L’Estrange had recognised the 
fact that geography and geology differ in their points 
of view, he would probably have given less import- 
ance to some and greater importance to other parts 
of his physical geography. 
The main feature of Mr. L’Estrange’s work is an 
attempt to graduate the subject in three stages, A, 
B, and C, the A stage suitable to the lower section 
of a school in which a boy may spend two years, the 
others to the higher sections. The boy is intended 
in each successive stage to go over the same ground, 
to gain additional knowledge and to exercise his 
thoughts on more difficult problems in the higher 
stages, but “all without overlapping or illordered 
acquisition of knowledge.’? This plan is followed 
both in the text and the maps, and the manner in 
which it is carried out in the maps is one of the 
most important contributions the author has made 
to the accomplishment of his task. 
The plan is in a large measure sound, but probably 
most teachers will be disposed to think that he has 
pushed the idea of covering the same ground at every 
stage too far. They will question whether some of 
the subjects dealt with are suited for the A stage at 
all; for instance, that of map projections, which is 
distributed in a very unsatisfactory manner over 
stages A, B, and C. This fault, however, can be 
remedied by the teacher himself reserving the entire 
subject for the C stage. It is a more serious defect 
where we find that a reference to a higher stage is 
necessary to the complete understanding of a lower 
one, or ideas suited only to a more advanced stage are 
introduced in the treatment of subjects quite proper to 
a less advanced stage. Thus on p. 12, after the con- 
sideration of the whole subject of running water, we 
are suddenly introduced in stage A to the conception 
of alluvial valleys, explained as ‘‘ flat plains of rich 
soil deposited by rivers in their lower courses ’’; yet 
in the general treatment of running water in the A 
stage there is no account of the formation of such 
plains, to understand which one has to consider an 
action (of a quite simple character) reserved for the 
C stage, while in the A stage of the general matter 
we are introduced to the very difficult conception of 
