110 
now rise and fall each in its own place; they 
pose, therefore, in the film and impress their 
form upon it, the largest movement giving the 
largest impression, and where the movement is 
naught the impression is naught.”’ 
Part II., by Mr. Tallent, is devoted to three- 
color photography. It opens with an element- 
ary treatment of spectrum work as applied to 
the study of color and color mixtures. Follow- 
ing this comes a very complete account of color 
curves, and the reproduction of various colors 
by the synthesis of three primary spectrum 
colors. Ives’s beautiful method is again de- 
scribed, together with fuller details regarding 
the preparation of color records, the preparation 
and use of color filters and other details. The 
various other modifications of the three-color 
scheme are treated, closing with a chapter on 
Wood’s diffraction process. It seems a pity 
that fuller working details of some of the 
methods of producing colored transparencies 
by the superposition of dyed films, are not 
given. However, there are hints enough to en- 
able one to experiment along these lines if so 
inclined. 
Part III., by Mr. Senior, is a dozen or so 
pages on the Lippmann process, with formule 
for the preparation of the emulsion. There is 
a good deal of repetition in the book, as is 
usually the case in symposia of this sort. It 
will, however, be found very useful as a refer- 
ence book by those desirous of experimenting 
with any of the processes. 
BOOKS RECEIVED. 
Lectures on the Lunar Theory. JoHN CoucH ADAMS. 
Edited by R. A. SAmMpson. New York, The Mac- 
millan Company ; London, Cambridge, University 
Press. 1900. Pp. 88. $1.25. 
Knowledge, Belief and Certitude. FREDERICK STORRS 
TURNER. New York, The Macmillan Company ; 
London, Swan, Sonnenschein & Company. 1900. 
Pp. vili+484. $2.25. 
Engineering Chemistry. THoMAS B. STILLMAN. East- 
on, Pa., The Chemical Publishing Company. 1900. 
Vol. IL., pp. xxii+503. $4.50. 
Elementary Organic Analysis. 
pict. Easton, Pa., The 
Company. 1900. 
FRANCIS GANO BENE- 
Chemical Publishing 
Pp. vi+86. $1.00. 
SCLENCE. 
[N.S. Vou. XIII. No. 316. 
A Text-book of Urine Analysis. Joun H. Lone. 
Easton, Pa., The Chemical Publishing Company. 
1900. Pp. iv+249. $1.50. 
Evolution of the Thermometer. HENRY CARRINGTON 
Botton. Easton, Pa., The Chemical Publishing 
Company. 1900. Pp. 98. $1.00. - 
The Chemists’? Pocket Manual. Richard K. M®ADE. 
Easton, Pa., The Chemical Publishing Company. 
1900. Pp. vii+-204. $2.00. 
Handbook of Practical Hygiene. D. H. Brerany. 
Easton, Pa., The Chemical, Publishing Company. 
1899. Pp. 164. $1.50. 
Coneretions from the Champlain Clays of the Connecticut 
Valley. J. M. ARMS SHELDON. Boston. 1900. 
Pp. 45. Plate xiv. 
Annual Report of the State Geologist of New Jersey for 
the Year 1899: Forests. Trenton, N. J.,MacCrel- 
lish & Quigley. 1900. Pp. xvi+327. 
Nature’s Miracles: Electricity and Magnetism. Eut- 
SHA GRAY. New York, Fords, Howard & Hul- 
bert. 1900. Pp. vi+248. §$.60. 
SCIENTIFIC JOURNALS AND ARTICLES. 
THE January American Journal of Physiology, 
the concluding number of Vol. IV., records in 
the initial paper further interesting results ob- 
tained by Loeb in his study of artificial parthen- 
ogenesis. Loeb has caused the eggs of Cheetop- 
terus, an annelid, to develop into free swimming 
larvee by simply placing the eggs in various 
solutions which cause them to lose water. Po- 
tassium ions, however, have peculiar power 
over these eggs which grow to the trochophore 
stage ina KCl solution with an osmotic pressure 
coasiderably lower than that of sea water. A 
slight addition of HCl to the sea water also 
causes the eggs to develop. Loeb carefully 
observed the morphological changes in the 
eggs during their development, and found 
that although the artificially produced trocho- 
phores may be indistinguishable from those 
arising from fertilized eggs, yet the processes of 
segmentation varied so greatly that these proc- 
esses must be regarded as distinctly a function 
of the constitution of thesea water. These ob- 
servations, together with those on the formation 
of giant embryos by the fusion of two or more 
eggs, have an important bearing on develop- 
mental mechanics and cell lineage. Loeb con- 
cludes with a consideration of the relation 
