A. W. Wright—Polarization of the Zodiacal Light. 455 
ization passes through the sun, as nearly as it was possible to 
fix its direction. In no instance when the sky was clear enough 
to render the bands visible, did their position, as determined by 
the observations, fail to agree with what would be required by 
polarization in a plane throughthe sun. Not the slightest trace 
of bands was ever seen when the instrument was directed to 
other portions of the sky. 
These observations, for the most part, were made in the ten 
days preceding new moon in January and February of the 
present year. During this time there was an unusual number 
evenings in March and April also were improved in verifying 
the results previously obtained. The absence of the moon, and 
is polarized. The failure of the common apparatus to detect it 
shows that the proportion is not large, but it must be recollected 
that for a light so very faint much greater differences of inten- 
sity are imperceptible than in cases where the luminous intensity 
1s greater. The determinations were made as follows. A bundle 
of four pieces of excellent plate-glass was placed vertically at 
the center of the horizontal divided circle of a Deleuil’s 
goniometer, the telescope of which was replaced by the polar- 
ized light is passed through it, but on turning the glass plates 
bands become visible corresponding to po ] 
Plane. Theamount of the light polarized by refraction through 
ta oe lates at different incidences has been calculated by 
rof. W. 
pl } 
the table. The results given in the table correspond very well 
with those obtained by Brof Pickering,+ who verified his values 
* Monthly Notices of the Royal Ast. Soc., March 10, 1871, p. 162. 
+ This Journal, III, vol. 7, p. 102. 
