372 A. W. Wright—Polariscopic Observations of Comet c, 1881. 
the San Pedro bce at these beds are fossiliferous, though not 
to the same extent as the ore-beds. e presence of marine 
fossils was not ascertained until just before leaving the place, 
and but a few minutes remained in which to collect. The 
specimens therefore are such only as could be broken hastily 
from the weathered surface of the beds, and in most cases suf- 
fice jor merely generic Sie Gee pate The list as determined 
b R hitfield is as follow 
Outre rea gla br ra ; Adonis: Corbula, 3 species; Camptonectes ? ; 
Tellina ?, arid a fragment of some gasteropod. 
ART. Ss occa hei Observations a oe c, 1881; by 
ARTHUR W. Wri 
THE path of this comet in the sky did not bring it into posi- 
tions the most favorable for observation, but while near Pog 
vented the attainment of anything li omplete series of 
observations, it was found possible to establish the fact of 
polarization, and even to secure some measurements. wing 
to the extreme faintness of the light, these oa re obtained with 
some difficulty, and were limited to a small n 
The first successful observation was made on A aaiet 16, 
from 9" to 10" Pp. M., local time. With a double-image prism, 
placed before the eye- piece of a Cinidtaeker having an aper- 
ture of three inches, and a apocrine power of about eight 
diameters, the light was easily seen to be polarized in a plane 
passing through the sun. That fates sai be no doubt upon 
this point, two other persons were requested to view the images 
as they appeared in the instrument. Both found one of them 
fainter in certain positions of the prism, and in every case 
correctly designated that one which accorded with polarization 
in the direction above described, and this without any intima- 
tion as to the result to be expected, The light was just suffi- 
cient, when the polarimeter was applied, to enable the bands to 
be seen with great difficulty, but measurements were impossible. 
A few evenings later some polarimetric determinations were 
obtained, the results of which are brought together in the 
annexed table. The instrument and method employed were 
the same as described in the account of observations upon 
comet &.* Column I gives the date and local time; in column 
* This Journal, vol. xxii, Aug., 1881, p. 142; Copernicus, No. 8, p. 157; The 
Observatory, No. 53, p. 253. 
