Aveust 18, 1899. ] 
tational, E is constant along the same stream 
line (filet) defined by the equations 
dx dy dz 
iy OD oy wae 
where uw, v, w, are the component velocities of 
the particle ; 8d, when the motion is steady 
but rotational, EF is also constant along the 
same vortex line, defined by the equations 
where p, q, 7 are the component spins. 
Then follow a proof of the theorem of Helm- 
holtz, above cited, and of the theorem that in 
the case of a liquid filling a recipient the ve- 
locity components u, v, w are determinate if 
the spins p, g, r are known at any instant. 
Several very instructive special cases of vortex 
motion are also considered; and the chapter 
closes with an exposition of the problem of the 
motion of a solid in a liquid, application being 
made especially to the case of pulsating spheres 
studied by Bjerknes. R. 5S. W. 
The Elements of Vital Statistics. By ARTHUR 
NEWsHOLME, M. D. Third Edition. Lon- 
don, T. Swan Sonnenschein & Co., and New 
York, The Macmillan Company. 1899. Pp. 
xii + 353. 
That a third edition of this book has been 
demanded within ten years of its first appear- 
ance is gratifying evidence of a growing public 
interest in Vital Statistics and an appreciation 
of sound and careful work. Vital Statistics, 
interpreting that phrase in a somewhat larger 
sense than is done by this writer, is probably 
the best avenue along which to approach the 
general field of statistics. It is the oldest, 
most developed and most systematized branch 
of the subject, and, if properly handled, can be 
made of great interest even to beginners. For 
these reasons I have long felt that the book of 
Dr. Newsholme was, perhaps, as good an intro- 
duction to statistics as anything in the English 
language. There is no American book to be 
compared with it, for the articles by Dr. J. 8. 
Billings and Dr. Roger S. Tracy are buried in 
pages of other matter, one in a medical journal 
and the other in an encyclopedia, and neither 
vies in simplicity or fullness of treatment with 
the present work. This third edition is almost 
SCIENCE. 217 
a new book, embracing fewer tables, more 
graphic illustrations, more references to results 
obtained in foreign countries and many new 
subjects. From the American standpoint it 
may be criticised as confined somewhat too 
closely to topics which especially interest Eng- 
lish sanitary and medical statisticians. But as 
England is facile princeps in this field and the 
United States as a whole is inferior, not merely 
to those countries of Europe with which we 
naturally compare ourselves, but even to 
Russia, Greece, Spain and the colonies of Aus- 
tralia, the objection is not a serious one. Dur- 
ing years of critical use of Dr. Newsholme’s 
book I have never found in it a serious error 
of statement and the argumentative parts are 
sound, temperate and convincing. It is a typ- 
ically English book, caring little for theory or 
refinements of analysis unless they have a clear 
bearing on the results, but strong in all such 
practical discussions as statistical evidence for 
the utility of vaccination, causes of infant mor- 
tality, or the fallacies to which statistical argu- 
ments are exposed. WALTER F. WILLCOX. 
CENSUS OFFICE. 
BOOKS RECEIVED. 
Anatomie des Frosches. A. ECKERT and R. WIEDER- 
SHEIM. Revision by Dr. ERNEST GAUPP. 2d 
Edition. Braunschweig, Friedrich Vieweg und 
Sohn. 1899. 2d Part. Pp. 237-548 + xii. 
Praxis und Theorie der Zellen-und Befruchtungslehre. 
VALENTIN HACKER. Jena, Gustav Fischer. 
1899. Pp. viii+ 260. Mark 7. 
Fizirung, Farbung und Bau des Protoplasmas. ALFRED 
FISCHER. Jena, Gustav Fischer. 1899. Pp. 
x+362. Mark 11. 
Folk-lore in Borneo. WILLIAM HENRY FURNESS. 
Wallingford, Pa., Privately Printed. 1899. Pp. 30. 
Sewage Analysis. J. ALFRED WANKLYN and WIL- 
LIAM JOHN COOPER. London, Kegan, Paul, 
Trench, Treiibner & Co., Ltd.; Philadelphia, J. B. 
Lippincott Company. 1899. Pp. xvi+220. $2.00. 
New Plane and Solid Geometry. WOOSTER WOODRUFF 
BemMAN and DAvip EvuGene Situ. Boston, 
Ginn & Company. 1899. Pp. ix+382. 
SOCIETIES AND ACADEMIES. 
AMERICAN ASSOCIATION FOR THE ADVANCEMENT 
OF SCIENCE—PRELIMINARY PROGRAMS. 
SECTION A, MATHEMATICS AND ASTRONOMY. 
‘REPORT on Progress in Non-Eulidean Geom- 
etry,’ George Bruce Halsted, University of 
Texas, Austin, Texas. 
