144 A.W. Wright— Polarization of Light from Comet b, 1881. 
I. I. il. ae 8 ee 
June 29, 15 to 25, A. M. 23°8 eas 60°°5 
June 30, 1" to 2h, a.m. 17°6 178 58° 
2 
July 1, 11 to 12" 30™ p, M. 20°1 19°3 54°°5 
17 
July 2, 10" 30™ to 11" p.m. 
l 
July 3, 10" 30™ to 12" p.m. —-18°0 18°3 51° 
; 18 
July 21, 115 30™ p.m. to 1, 
July 22, 118 30” p.m. to 14. 
angles of incidence it is seen that they decrease together. No 
definite maximum was made out, but the existence of one near 
or beyond 60° is perhaps indicated by the fact that polarization 
was less easily observed on the evenings previous to June 29, 
and by the more rapid variation in the percentages on this and 
the two succeeding evenings. At first sight the large percent- 
ages obtained in the earlier observations appeared to indicate 
reflection from a gaseous substance, but the numbers foun 
later, and especially the relation of all the values to the angles 
of incidence, render an inference as to the character of the 
reflecting material more difficult. It is not improbable that 
the constitution and physical condition of the matter composing 
the tail were variable, and this circumstance would introduce 
changes in the proportion of polarized light, in addition to 
those produced by the alteration in the angle of the reflected 
rays. The fact of polarization shows that a large part, probably 
the greater part, of the light coming from the tail is reflected 
sunlig 
Yale College, July 25, 1881. 
