864 
sides brief articles, including a note on a fossil 
flower related to Hydrangea. Thesupplement, 
devoted to ‘The Families of Flowering Plants,’ 
by Charles Louis Pollard, treats of the Sarrace- 
niales and Rosales. 
AN editorial article in the Observatory accuses 
the Astrophysical Journal of reprinting without 
credit an article on the ‘Siderostat’ by M. 
Cornu. As the Bulletin astronomique, in which 
the French copy of the article appeared, was 
published in February, 1901, and the number 
of the Astrophysical Journal in March, 1901, 
the editor of the Observatory must appreciate 
the promptness of American methods. As a 
matter of fact important European articles on 
astrophysics are published by the authors simul- 
taneously in the Astrophysical Journal. This 
makes the concluding sentence in the editorial 
in the Observatory interesting : ‘‘ they print the 
same paper in several journals, so that it may 
be widely read, whereas in Hurope we have 
made it a point not to reprint.’’ 
SOCIETIES AND ACADEMIES. 
SECTION OF ANTHROPOLOGY AND PSYCHOLOGY 
OF THE NEW YORK ACADEMY OF SCIENCES. 
A REGULAR meeting of the Section was held 
on April 22d, with Professor Farrand in the 
chair. Professor Eberhardt Fraas, of Stuttgart, 
a corresponding member of the Academy, was 
introduced by Professor Osborn, and briefly ad- 
dressed the meeting. 
Mr, A. L. Kroeber presented some ‘ Notes on 
the Arapahoe Indians.’ In this paper the social 
and ceremonial organization of these Indians 
was compared with that of other Plains Indians. 
On superficial examination various tribes ap- 
pear to be organized according to identical 
principles, but fuller knowledge generally re- 
veals differences among the similarities. From 
this it was concluded that such terms as gens, 
band, age-fraternity and dance-society have no 
stable or exact meaning and hence little de- 
scriptive value, detailed information being the 
great desideratum. : 
Professor C. H. Judd reported an experi- 
mental study on ‘Practice in Visual Percep- 
tion.’ It is a generally recognized fact that 
an illusion grows weaker as the observer be- 
SCIENCE. 
[N.S. Von. XIII. No. 335, 
comes more familiar with it. A quantitative 
determination of the disappearance of the illu- 
sion seen in the Muller-Lyer figure was the sub- 
ject of the paper. ‘Two series of results were 
reported, one from an observer who looked for- 
ward to the disappearance of the illusion, the 
other from an observer who did not know that 
the illusion would disappear and did not dis- 
cover that it was disappearing. In both cases 
the illusion disappeared in about 1,000 obserya- 
tions. The curves of practice differ in form and 
show many details of effects of pauses. In the 
case of the first observer the effects of the prac- 
tice gained in the first series was easily marked 
in all the additional series which were per- 
formed with other figures and with other posi- 
tions of the first figure. In the case of the 
second observer the effect of the practice was 
in some cases positive, but in one case it was so 
decidedly negative that it exaggerated the illu- 
sion and prevented any disappearance of it 
through a series of 1,500 observations. 
Professor EH. L. Thorndike, in a paper dis- 
cussing the ‘Origin of Human Intellect,’ pro- 
posed as a working hypothesis that the devel- 
opment of ideation and rational thinking in the 
human species was but an extension of the 
typical animal form of intellect. He defended 
this hypothesis by showing that mere increase 
in the number, delicacy and complexity of as- 
sociations between sense-impressions and im- 
pulses might give concepts, feelings of relation- 
ship and association by similarity as secondary 
results, that in the human infant this seemed 
to occur and that down through the vertebrate 
phylum a clear evolution of the associative 
processes along these lines could be traced. 
The last report of the evening was by Dr. R. 
S. Woodworth, on the ‘ Voluntary Control of 
the Force of Movement.’ By recording simul- 
taneously the force of a blow struck by. the 
hand and the extent of the movement prelimi- 
nary to the blow, it is possible to see how far 
the force is dependent on the extent. The re- 
sults showed a certain degree of correlation be- 
tween the two, but comparatively a slight de- 
gree. The inference was that the force of the 
movement was only partially and loosely de- 
pendent on the extent, and that the control and 
perception of the force of a movement were in 
