©. A. Young—sSpectroscopic Observations upon the Comet. 185 
Three photographs of the comet’s spectrum have been taken 
with this arrangement with exposures of 180 minutes, 196 
seen while the photography was in progress. It will take 
some time to reduce and discuss these photographs and pre- 
pare the auxiliary photographs which will be necessary for 
their interpretation. For the present it will suffice to say tha; 
the most striking feature is a heavy band above H which is 
divisible into lines, and in addition two faint bands, one be- 
tween G and / and another between / and was very 
careful to stop these exposures before dawn, fearing that the 
spectrum of daylight might. become superposed on the cometary 
spectrum. 
It would seem that these photographs aac ae the hypoth. 
esis of the presence of carbon in comets; but a series of com- 
parisons will be necessary, and it is not searubakte that a part 
of the spectrum may be due to other elements. 
271 Madison Avenue, New York. 
ArT. XXV. ol eae Observations ae the Comet b, 1881 ; 
by Professor C. A. You 
WHILE the Comet was brightest the weather at Princeton 
was very tantalizing. From June 25 to July 3, the comet was 
seen and observed on every night except June 30, and on none 
of them, except July 2, more than an hour at a time, the work 
being invariably interrupted by clouds or fog. 
or the spectroscopic observations I have “used both the one- 
prism instrument, by the Clarks, which belongs with the Equa- 
torial, and the solar spectroscope by Gr ubb—the latter with 
di laps hark powers varying, according to occasion, from two to six 
dense glass prisms. e telescope was the 94 inch Equatorial. 
The following are the principal facts made out so far: 
— oo spectrum of the nucleus was found to cad We nie 
t simply continuous; but on several occasions, esp 
salty Tage 25, July 1, and July 12, it showed siatinee bande 
coinciding with those of the spectrum of the coma. When 
brightest the spectrum could easily be followed from the neigh- 
borhood of B to a. point well above G; and in the lower por- 
tion it showed color stron 
2.) The spectrum of one ‘of the jets which issue from the 
nucleus was isolated on June 29th and found to be continuous. 
I think this was usually the case with the jets, but it is seldom 
possible to separate the spectrum of a jet from that of the nu- 
cleus sufficiently to be perfectly sure 
Am. Joor. nia” _ Vou. XX, No. 128,—Aueust, 1881. 
