Juty 14, 1899. ] 
quent references to original articles are cited in 
the foot-margins. 
This is the first American text-book on purely 
physical crystallography, and, containing, asit 
does, the sum of what is at present known on 
the subject, it must commend itself to every 
student of the science. 
A. S. EAKLE. 
HARVARD UNIVERSITY. 
Algebra for Schools. By GEORGE W. EVANS, 
Instructor in Mathematics in the Euglish 
High School, Boston, Mass. New York, 
Henry Holt & Co. 1899. 
This book is a fresh treatment of the topics 
commonly found in algebras for schools. It is 
by no meansa mere compilation or reprint with 
slight alteration of texts now before the public. 
While, of course, it is not, nor pretends to be a 
contribution to knowledge, it is distinctly what 
the author has sought to make it, a real contribu- 
tion to the art of presenting knowledge to the 
beginner. Ordinary algebra is, in its elements 
at least, nothing but an extension and refine- 
ment of common sense applied to number. 
Consistently with this idea, the author’s arrange- 
ment of topics, as well as his method of attack 
—in both of which respects there is a notice- 
able departure from tradition—are well adapted 
“to preserve the pupil from the besetting sin of 
conceiving algebraic operations as a species of 
legerdemain.’ An appeal is invariably made, 
in the first instance, to the reader’s practical 
sense. Theory is not slighted ; being approached 
through concrete examples, it is, however, 
rather produced than presented, and its correct- 
ness is not so much demonstrated as its reason- 
ableness is shown. As instances of this proce- 
dure may be cited the treatment of signs, 
.imaginaries and exponents. In case of the 
latter two themes the spirit is particularly com- 
mendable. Among other specially praiseworthy 
features are the chapter on the abbreviation of 
rules by means of symbols; the prominence 
given to identities, together with the clear dis- 
tinction between the latter and equations of 
condition ; the geometric interpretation of the 
simplest equations ; the extended and accentu- 
ated treatment of factoring and of the quadratic 
equation ; the discussion of the notions of con- 
SCIENCE. 55 
' 
stant, variable and limit, and the abundance 
and variety of exercises not copied from other 
works. An easily detectable slip in logic oc- 
curs on p. 105 in justifying steps (4) and (6) by 
reference to axiom A. The proper justification 
is that such equations are satisfied if either 
factor be equated to zero. 
An adequate characterization of the book is 
impossible in so short an account. That it is 
immensely superior to the average of its rivals 
is obvious on comparison. It should be added 
that the book is written in excellent English, 
and is well printed and well bound. 
C. J. KEYSER. 
CoLUMBIA UNIVERSITY. 
The Emotion of Joy. By GEORGE VAN NEss 
DEARBORN, A.M., M.D. New York, The 
Macmillan Company. 
This monograph opens with a rather extended 
vindication of parallelism, but the writer cannot 
keep to this point of view, e. g. pages §, 13, 
14,16. But at any rate parallelism at present 
is metaphysical, exact coincidence of external 
expression and internal emotion is yet to be 
shown experimentally, and, as assumption, it is 
obscurrantist in breaking up the universal 
causal nexus, which is the basis of science, and 
putting a bare dualism for rational coordina- 
tion. Of course the difficulty of experiment 
seems insurmountable, since the agent can only 
indicate to us the moment of his emotion by an 
expression. After outlining the general paral- 
lelistic doctrine of emotion, Mr. Dearborn pre- 
sents some experiments which are so hypothet- 
ical as to be only of the slightest value in 
revealing the opinions of fourteen persons as 
to how they would feel. and act if given sums of 
money from ten to ten thousand dollars. Much 
the most interesting and valuable part of this 
paper is that which reports researches on the 
effects which pleasantness and unpleasantness 
have upon the involuntary muscular move- 
ments. Itis particularly interesting to notice 
that ‘‘the left hand appears much more sensi- 
tive to involuntary reaction than the right, and 
this was to be expected, perhaps, most of the 
subjects being right-handed and, therefore, with 
their right hand ‘ civilized,’ so to say, away from 
the origina] biological habits of emotional con- 
