508 
and as the solutions approach high concentra- 
tion, there is again a falling off showing the ex- 
istence of maximum points on the curves. So- 
lutions of calcium salt contain so little normal 
carbonate when in equilibrium with air, that 
practically they may be considered as contain- 
ing only the hydrogen carbonate. With rise of 
temperature in all cases, there is an increase in 
the proportion of normal carbonate in the solu- 
tion, and at 100° C. all the base is combined as 
normal carbonate for practically all concentra- 
tions. A theoretical discussion accompanied 
the paper, and practical applications of the re- 
sults were pointed out. 
L. 8. Munson, 
Secretary. 
PHILOSOPHICAL SOCIETY OF WASHINGTON. 
THE 531st meeting was held March 2, 1901. 
Under the head of informal communications 
Mr. Farquhar stated that eye observations on the 
Nova and Perseus showed considerable fluctua- 
tions in brillianey from night to night. Mr. 
Bauer stated that the Toronto magnetic ob- 
servations at the time of the Solar eclipse 
showed a slight disturbance coincident with the 
passage of the sun’s shadow. Analysis shows 
that this is due to causes outside the earth’s 
crust, and probably due to changes in the upper 
atmosphere caused by the passage of the 
shadow. 
The first regular paper was a report by 
Father Hagen on ‘Progress in Astronomical 
Photometry.’ It grouped the facts into four 
classes : 
1. Photometric Catalogues with regard to 
brightness and color of stars. Special mention 
was made of the Harvard Photometry and of 
Osthoff’s catalogue of star colors. 
2. Original Observations of Variable Stars were 
mentioned, in particular those published lately 
by Peck, Knott and Pickering. 
3. The Physical Explanation of the light varia- 
tions is advanced by the discovery of coinci- 
dence between the light curves and velocity 
curves in the three variable stars: 5 Cephei, 
7 Aquilae and ¢ Geminorum. 
4, Various Charts for Variable Stars, dis- 
tributed or published for the convenience of ob- 
servers, were mentioned, with special reference 
SCIENCE. 
[N. S. Von. XIII. No. 326. 
to Pogson’s charts. This part of the report 
was illustrated by lantern slides. 
The next paper was a report by Mr. Radel- 
finger, on ‘Progress in Pure Mathematics in 
1900.’ This dealt first with important books, © 
referring to the great Mathematical Encyclo- 
pedia now in course of publication, and to For- 
syth’s ‘Differential Equations’ in two vol- 
umes. A brief historical account of the treat- 
ment of the ordinary differential equation from 
the time of Briot and Bouquet introduced an 
outline of Painlevé’s very recent and success- 
ful attack on the equation of the second order : 
he had discovered three new uniform functions, 
and completely solved the problem of determin- 
ing all equations of the second order whose 
integrals are uniform functions. Painlevé’s 
method promises important results from its 
application to equations of higher orders. 
Professor See’s report on the ‘ Progress of 
Astronomy in 1900’ dealt very briefly with the 
publication of the results of the observations 
on the Transit of Venus; the observations on 
Eros, in which about 50 observatories are en- 
gaged ; the discovery of several hundred double 
stars, and the publication of double-star cata- 
logues; The observations at the Naval Observa- 
tory of planetary diameters with a color-screen ; 
and Rees’s new determination of the con- 
stant of observation, which he finds to be 
20/7.464. 
CHARLES K. WEAD, 
Secretary. 
GEOLOGICAL SOCIETY OF WASHINGTON. 
Art the 111th meeting, held on February 27, 
1901, at the Cosmos Club, the following papers 
were presented : 
Memorial of Thomas Benton Brooks: Mr. BAt- 
LEY WILLIS. (Published in ScrencE March 
22.) 
Morphogeny of Southern Alaska: Mr. G. K. GIL- 
BERT. 
Mountain Structure in the Trans-Pecos Province 
of Texas: Mr. Roperr T. HILL. 
The last two papers were illustrated by lan- 
tern slides. 
F. L. RANSOME, 
DAvID WHITE, 
Secretaries. 
