DECEMBER 10, 1897.] 
affected by the influence of environment, I can- 
not acknowledge that any proof of the trans- 
formation of the fundamental features of types 
exists. 
In our inyestigations on the early history of 
mankind three methods are available, each di- 
rected to a certain series of phenomena—phys- 
ical type, language, customs. These are not 
transmitted and do not develop in the same 
manner. The one persists when the other 
changes, but all may be made to contribute to 
the solution of the general problem. The study 
of the distribution of languages permits us to 
make nicer divisions and to follow historical 
‘changes in greater detail than that of the dis- 
tribution of physical types. But often the lat- 
ter give evidence in regard to phenomena 
which cannot be approached by linguistic 
methods. The distribution of the Alpine type 
of man in Hurope, or that of the Sonoran type 
in North America, may be mentioned as in- 
stances of this kind. It would be absurd to 
state that in these cases similarity of type does 
not prove blood-relationship, because there is 
no linguistic evidence to support it. On the 
contrary, the physical investigation supplies 
evidence that cannot be gained by linguistic 
facts. The three methods mentioned above are 
all equally valuable, but since they do not refer 
to the same classes of facts it must not be ex- 
pected that they will clear up the same inci- 
dents in the early history of mankind, but all 
may be utilized with equal advantage in the 
study of this subject. 
In regard to the affinities of the American 
race to other races Dr. Ehrenreich seems to be 
inclined to consider it as equally closely related 
to the Asiatic and to the European races. He 
lays particular stress upon the proportions of 
the body and the form of the hair as distin- 
guishing the Americans from the Asiaties. In 
this opinion he agrees to a certain extent with 
Brinton. It would seem to me that in determ- 
ining the position of a race we should be guided 
by the morphology of its most generalized forms, 
namely of women and children. The far-reach- 
ing similarity between American and Asiatic 
children and women is very striking. They 
have in common the wide and rather low nose, 
the form of the eye and of the maxilla. The 
SCIENCE. 
883 
physiognomie similarity is so great that it 
would seem to be of greater weight than the 
variable proportions of the body which are 
much more subject to influences of environ- 
ment. FRANZ BOoAs. 
The Alternating-Ourrent Circuit: An Introduc- 
tory and Non-mathematical Book for Begin- 
ners and Students. By W. PERREN MAy- 
cock. London, Whittaker & Co. 1897. 
16mo. Pp. 97. Price, $1.00. 
It is the author’s purpose to convey some 
idea of single-phase alternating currents to the 
minds of those new to the subject, by means of 
plainly worded and non-mathematical language. 
In his preface (April, 1897) he states that the 
book forms the substance of a chapter in the 
forthcoming Volume II. of ‘ Electrical Light- 
ing and Power Distribution.’ With a thorough 
revision it would make an admirable chapter 
for such a book. Although the book is small, 
the reviewer appreciates the amount of labor 
that has been spent upon it in arranging the 
more important alternating current phenomena 
and discussing them in a manner suitable for 
non-mathematical beginners. The author has 
attempted to make his style simple and clear, 
successfully in the main, but with many start- 
ling lapses. What idea is conveyed to a reader 
(and he need not be a non-mathematical begin- 
ner) from the statement (p. 8), ‘‘The current 
in a given circuit is thus proportional to the 
distance traversed at each alternation by any 
given coulomb, C, multiplied by the number of 
alternations per second ; so that if the current is 
kept constant, when the frequency is doubled, 
the path traversed by any given coulomb will 
be halved, and vice versa.”’ 
We note error as well as confusion ; for ex- 
ample, on page 64 we are‘told that reactance 
varies directly as the inductance and the mutual 
induction. Asa matter of fact, mutual induc- 
tion in a case of a transformer diminishes the 
reactance ; for the primary circuit of a trans- 
former has less reactance when the secondary 
is loaded than when it is on open circuit. 
Again, it is stated (pages 64 and 85) that react- 
ance depends directly upon the inductance and 
the frequency, and inversely upon the capacity. 
This is true when the current lags behind the 
