438 Scientific Intelligence. 
then arises, how did the companion become detached from Biela. Was 
it by an internal explosion? Admitting the possibility of an explosion 
by which a cometary body might be torn into fragments, the rapid in- 
crease of size and brilliancy of the companion compared with Biela, 
from Jan. 13th to Feb. 16th, seems hardly explicable except upon the 
supposition of a continued transfer of matter from one body to the oth- 
er for an entire month. It seems then most natural to suppose that the 
cause of this continued transfer was the same as that of the first for- 
mation of the companion. If this formation appears mysterious, we 
have at least observed phenomena in the case of other comets which 
possibly may have some analogy with this. Halley’s comet at its last 
return was observed to emit streams of fiery matter, which presented 
the appearance of sectors of extreme brilliancy. The matter thus 
emitted from the head diffused itself in the direction opposite the sun, 
and formed the tail of the comet. ‘The attraction of these particles of 
matter for each other was scarcely, if at all, appreciable. Suppose 
however the existence of a feeble attraction among these particles. A 
few of these collecting together would form a nucleus to which other 
neighboring particles would be attracted, and thus the particles emitted 
rom the head would form a second nebulous body not unlike the com- 
panion of Biela. According to the rate of separation when first ob- 
served, these two bodies must have been together about the Ist of Jan- 
uary. At this time then we may suppose Biela’s comet to have com- 
menced emitting particles from its head, which uniting by feeble attrac- 
tion formed a small nebulous body. Perhaps when the repulsive force 
began to operate, it may have been for a time resisted by an envelop 
partaking somewhat of the character of a solid body; and when this 
resistance yielded, a considerable portion of the main body may have 
been at once detached by a sort of explosion. A fragment thus de- 
tached might attract to itself at least a portion of the stream of parti- 
cles-which continued to be emitted from the main body. Thus the 
companion increased at the expense of Biela until the 16th of Februa- 
ry, which was soon after its perihelion passage. At this time the dis- 
tance of the companion was such that it could no longer attract to it- 
self the matter repelled from Biela. It therefore ceased to grow, and 
indeed appeared to decline in brilliancy, perhaps from the loss of mat- 
ter which it emits in the same manner as Biela; although we have an 
example in the case of Encke’s comet of a body which habitually be- 
comes much less conspicuous after than before perihelion passage. 
3 On the whole it must be admitted that the phenomena of comets are 
toge ner anomalous. The comets of Halley, Encke and Biela, a 
