Chemistry and Physies. 407 
which is also oo of turning about a vertical axis. Two other 
divided circles measure the motion in azimuth and in declination, 
and allow the polariscope to be directed in any direction, and give 
also the codrdinates of the point of observation. The method of 
observation was to obtain upon the same divided circle the sigs 
of the ae of polarization of the sun and the trace of t 
of the An ingenious method of accomplishing this is detailed 
in the pies s memoir. The conclusions reached are as follow 
and minimum during the day. This phenomenon appears to a 
connected with the variable conditions of illumination of the a 
mosphere due to the height of the sun. 
(3) The manifestation of the magnetic influence of the earth 
upon the atmosphere, to which influence can be attributed a me 
deviation of the plane of ee of the light. Bicinarsn de 
oe aes et de Physique, Jan., 1880, p. 90. J. 
Measurements and law in iar oe Optics.—Dr. Kurr eae 
oo his experi riments upon the effect of electric tension on the 
a Aare in i canker of electrostatic force, and the state 
of molecular constraint that is associated with and is essential to 
that action, are very strongly confirmed by the new facts of elec- 
tro-optics. “The dioptric action of an mgesignie charged medium 
is closely related to the care stress of the medium, the axis of 
double refraction coinciding in eve case with the line of electric 
tension, and the double tolraction varying, certainly in CS, and 
probably i in all other pe a directly and simply as the inten 
ai of the tension.”— Phil. Mag., March, 1880, p. 
11. Connection between the laws of diffusion and Pioreiinds 
namics,—BoutzMaNnn, in a valuable paper, discusses the phenom- 
e cua tiatatontiation of @ork dite to aifunio n, and the 
maximum work which can be produced me ithe diffusion of gases 
at constant temperature.— Wien. Ber., 78, 
