“a 
a a 
= 
half as large as in A, oligostachyus. ) 
= _. On the Formation of the Tails of Comets. 
is Miiciopseitas aplindoides, | Muhl. ) 
C4 46. Arberopagon papillosus fer t -culmis. cecapiiicis ine 
ac, foliis lanceolato-linearibus planis margine et ad nervun 
smiesdiaibeath infra supraque ex papillis serrato-ciliatis; spicis 1 
subterminalibus biserialibus unilateralibus eanlusote; glumi 
papilloso-hispidis ; valva corolle perfectz exteriore ‘ifidas valvé 
eorollz neutrius brevissima hyalina ex basi triaristata. 
Sandy soil, Beardstown, Il]l—Very near Av iizestachaal 
Nutt., and resembling it closely, but distinct by the broader and 
hispid (not setaceous and smooth) leaves, the hispid (not pubes: 
cent) glumes, and the hyaline glume of the abortive floret Ss 
~ 147. Andr ogon scoparius, Michx. » 
ss. Poa Irsuta, Tichx.: 
“449, @ pectir inacea, Mié 
449, b: “Hordeum pusilfum, ‘Natt. ee - i 
P60. Woedsia Perriniana, Hook. ‘ ‘a om 
Art. XIV.—On. the Mode of Formation of the Tails of Comets 
by: Witttam A. Norton, Professor of Mathematics and Natura 
Philosophy in Delaware College. 
Ir is not my design, in’ \the present atflele, to furnish’a onli 
theory of the process by which the tails of ‘comets are forme 
from their heads.. This‘cannot be attempted, it is presumed 
with any reasonable hope of success, until more facts relative tt 
the structure and phenomena of comets have been accumulated 
But little more will now be: undertaken, than to disprove tht 
commonly received notion that the tail and head ofa‘ comet fort 
one connected mass, revolving as one body, and to establish tht 
opposing doctrine, that the tail is made up Of particles of matte! 
continually in the act of flowing away from the head. To do 
this intelligibly and effectually, however, it wilh first be necessal y 
to treat t briefly of the eg 
Physical oitituti of Cémets. . fs ef a 
‘What I have to offer upon this preliminary topic, mag Sals 4 
eniently arranged under o o— headey : viz. vd! The 
/ 
k 
