A.W. Wright— Polarization of Light from Comet b, 1881. 148 
the nucleus. The second and third of the observations of July 
1, in the list below, were made upon regions removed several 
degrees from the nucleus, but though the amount of polarization 
is somewhat less, and tends to confirm the above conclusion, 
the difference is hardly greater than would be accounted for by 
the errors of observation. Determinations of polarization at 
great distances from the nucleus were not possible, the light 
being too feeble. 
the light. 
The results of the observation are given in the following 
table. The date and local mean time for the series of each 
evening are given in column J. In column II are given the 
ten measurements. The numbers express the proportion of 
sun, referred to the nucleus or points very near it. It is 
obtained from the ephemeris of Peters,* combined with that of 
Oppenheim given in the Dun Heht Circular No. 24. The 
angles subtended at the comet by the earth’s radius vector at 
the dates of the ephemeris were obtained by a simple graphic 
process. With these a curve was constructed from which the 
atigles for the dates of the different observations were derived. 
These divided by two are the anglés of incidence. 
* Astronomische Nachrichten, No. 2381, p. 75. 
