108 
OUR BOOKSHELF. 
An Introductory Course of Continuous-current 
Engineering. By Dr. Alfred Hay. Pp. xii+ 
360. Second edition, revised. (London: Con- 
stable & Co., Ltd., 1916.) Price 6s. 6d. net. 
Like all Dr. Hay’s books, the present work will 
well repay the elementary student for the time 
spent on its study. It first treats of the ele- 
mentary laws of electromagnetics, then proceeds 
to deal with instruments, machines, secondary 
cells, electric lamps, switchgear, and conductors. 
In places it lacks depth, whilst such things as 
definitions, fundamental ideas, and the distinction 
between E.M.F. and P.D. are not quite so clear 
as they might be. 
The chapter on armature windings could be 
improved. The statements made regarding wave- 
windings have the ordinary two-circuit four-pole 
winding in view, and one at least of them is not 
even universally true for this. It is a mistake to 
hide from the student that many other wave- 
windings are possible, especially as some of them 
have practical advantages which will lead to their 
more extended use in future. 
The chapter on storage cells ought to have at 
least one illustration showing a complete cell or 
battery, and the diagrams showing the construc- 
tion of the plates might have been of a more 
modern type. The really useful primary cells 
should surely have found a place in “ Continuous- 
current Engineering.”’ 
The chapter on switchgear is to be especially 
commended, as it gives much more information 
than is usually found in a small general text-book. 
Although we have criticised several details, we 
are pleased with the book on the whole, and can 
recommend it to those requiring an elementary 
book on the subject. Davip ROBERTSON. 
My Yoruba Alphabet. By R. E. Dennett. Pp. 
xi+4s5. (London: Macmillan and Co., Ltd., 
1916.) Price 1s. 6d. net. 
TuoseE who have been accustomed to depend upon 
the classical work of Col. Ellis on the Yoruba 
people may be surprised at Mr. Dennett’s specu- 
lations. Ellis, a careful, competent writer, tells 
us that they worship a pantheon of nature deities, 
like Olorun, the sky-god, and phallic gods of 
fertility, like Elegba, to whom human sacrifices 
in a brutal form were, or are, offered. Of their 
higher spirituality he gives little or no evidence. 
Mr. Dennett, a competent philologist, starting 
from his own “firm conviction that all the works 
of the Great Creator of the Universe . . . con- 
form to one definite universal order, and that the 
spirit, or inner consciousness of man, moves in 
conformity to this universal order so long as that 
consciousness works in obedience to the dictates of 
its Great Author,” finds beliefs of a similar type 
among the Yorubas, who “are by nature deeply 
religious.” Their alphabet, as interpreted by 
him, expresses eight ‘Elemental Factors,” such 
as Authority, Morality, Potentiality, and so on. 
He claims that the summary of his results “should 
NO. 2450, VOL. 98] 
NATURE 
[OcToBER 12, 1916 
establish decisively and conclusively the syste- 
matic conformity of the construction of Yoruba 
words—especially the Yoruba primitive verbs— 
with the eight elemental factors of the Great 
Universal Order.” Whether*the hypothesis meet 
with acceptance or not, Mr. Dennett’s book wilh 
be useful to students of the Yoruba speech, and, 
in particular, the system of transliteration now 
proposed deserves careful consideration. 
Bacon’s War Maps. Europe, embracing all the 
Countries Involved. (London: G. W. Bacon 
and Co., Ltd., n.d.) Price 6d. net. 
Tuis folding war-map includes the greater part 
of Europe and is on a scale of 1: 4,000,000. It is 
politically coloured, fairly clear, and has a large 
number of names, but the only attempts to show 
relief is by a few stray caterpillar heights. In 
elevated areas like the Alps and the Carpathians 
these serve some purpose on a small-scale map 
like this, but in a lower region, such as the Allies’ 
western front, the few heights that are shown 
are more misleading than useful. In the Balkans 
the map fails to reveal the significance of the 
Vardar valley. Nor is there any attempt to show 
marsh lands, the military importance of which has 
been demonstrated on more than one front. In 
the matter of names there is some scope for eriti- 
cism. Halicz is not marked and Gorizia appears 
in the unusual form of Gorz. The map leaves 
scope for many improvements, which mieht have 
been carried out at the exnense of the somewhat 
glaring political colouring if cost was a first con- 
sideration. j 
LETTERS TO THE EDITOR. 
[The Editor does not hold himself responsible for 
opinions expressed by his correspondents, Neither 
can he undertake to return, or to correspond with 
the writers of, rejected manuscripts intended for 
this or any other part of Nature. No notice is 
taken of anonymous communications. ] 
Science in Education. 
Permir me to suggest that the science of man is 
scarcely ‘‘a vicious circle of introspective examina- 
tions,” but is itself ‘‘one of the realities of external 
Nature,” to use Prof. Soddy’s definitions (NATURE, 
October 5, p. 90). The science of man, as a biological 
phenomenon ethat changes the aspect of the inanimate 
world and interferes with most branches of living 
matter—as an organism the groups of which have a 
definite life-history of growth and decay of ability, 
sometimes called cycles of civilisation—or producing 
collective average mentality, which results in rapid 
expansion of ability combined with great destructive- 
ness—in all these ways the science of man appears 
to stand, like geology or astronomy, apart from all 
introspection. The purely scientific study by compari- 
son of these phenomena in mass-action, apart from 
individual movement, is as scientific as the study of 
mass-action of matter, physical and chemical, apart 
from tracing the movement of single atoms. The 
understanding of this seems to be academically needed 
if we are to escape from British narrowness, and see 
the world whole. F.R.S. > Bape 
