410 
PHILOSOPHICAL SOCIETY OF WASHINGTON. 
563d Meeting. February 14, 1903. 
President Gore in the chair. 
Twenty-seven persons present. 
Mr. J. G. Hagen spoke bn A peculiar type of temporary stars, 
the variation of which is of so short duration that it cannot be 
confirmed by an independent second observer. Five instances 
are known, reported by authorities of the highest standing, one 
of the observations being made by Scheiner in 1612, but never 
understood till recently. [Published in The Astrophysical Jour¬ 
nal, vol. xvii, Eo. 4, May, 1903.] 
The paper was discussed by Messrs. Marvin, Wead, Hayford, 
Day, and Gore. 
Mr. C. W. Waidner discussed the practical Methods of meas¬ 
uring temperatures and the accuracy attainable by them. He 
spoke of the present condition of mercurial thermometry from 
—35° to +550° 0. and the development of suitable kinds of 
glass for thermometric purposes; of some applications of plat¬ 
inum-thermometers, thermo-electric and specific-heat pyrometers; 
and of the estimation of temperatures beyond the range of these 
methods by extrapolation, using Stefan’s or Wien’s radiation- 
laws: thus, the temperature of the arc lamp is estimated at 
3700° 4200° C. [Published in Proc. Engineers Soc. of West¬ 
ern Pennsylvania, Sept., 1904.] 
Messrs. Green, Abbot, and Day took part in the discussion. 
564th Meeting. February 28, 1903. 
President Gore in the chair. 
Mr. Abbot presented an elaborate approximate method for the 
quadrature of the circle, recently described by a correspondent of 
the Smithsonian Institution. 
Mr. C. F. Marvin then spoke on The Seismograph. The early 
instruments were crude and ineffective; but the earthquake in 
Japan in 1880 led to the formation of a Seismological Society 
and the development there of the modern type of instruments; 
in this development two men who have since been members of 
