THE 
AMERICAN 
JOURNAL OF SCIENCE AND ARTS. 
[THIRD SERIES] 
rs 
> 
Art. XXI.—Coggia’s Comet—its Physical Condition and Struc- 
ture. Physical Theory of Comets; by Prof. W. A. Norton. 
ments of the pa ted by M. 
Schulhof (Astr. Nachr., No. 2003). T=1874, July 885664, 
G. M. T., 7=271° 6 195, O=118° 44’ 25’°3, 1=66° 20’ 
58’6, log. g=9°829826, which gives, per. dist. g=0-67581. 
Motion direct. ° 
Nature and Condition of the Cometic Matter.—The following 
are the general results of. the observations made with the spec- 
troscope and polariscope* with the view of ascertaining the 
nature and condition of the matter of the comet; in the nucleus . 
and coma or envelopes, and as more widely diffused in the tail. 
(1.) The light of the tail and coma was partially polarized in 
a plane through the axis of the tail. 
(2.) The spectrum of the comet consisted of three or more 
bright bands on a continuous spectrum. This continuous spec- 
trum was faint on July 7, but became much brighter by July 
14. The three bright bands were identical with those obtained 
by passing a spark from an induction coil through gaseous 
* Month. Not. . Soc., 187 489 to 491; 1874-5, p. 83. 
Aatz. Nachr,, No. 2018 9p. 181082 
Am, Jour. Scr.—Tarrp Senet. Vou. XV, No. 87.—Maxcu, 1878, 
