SSS 
ON THE COMET OF 1843. 89 
ble? Notatall. Beginning from the 27th of January, the comet appeared above 
our horizon, and rose up higher day by day. The visibility of the tail should 
have commenced still sooner, and with a splendour surpassing that which it 
assumed in the month of March, increasing daily through the month of Fe- 
bruary, crossing the meridian every evening with the stars in the constellation 
Lepus. Nothing of all this occurred. It was seen suddenly immediately after 
the perihelion in full daylight only a few degrees from the sun, five or six 
degrees in length, which probably answers to more than ten times as much 
seen in the night time. The spectators of it in tropical countries know not 
how to find words to express the greatness and magnificence of its appear- 
ance. When it unfolded itself to our eyes towards the 18th or 19th of March, 
it was already much diminished in splendour, as we find by the unanimous 
assertions of witnesses, and yet it excited general surprise in these countries. 
On the 21st of March my pupils observed the tail, already sensibly shortened 
to the naked eye, as far as n Leporis, whilst 1 could follow it in the finder 
beyond Sirius, leaving that star to the south. Thus the naked eye only saw 
a length of tail=23 the distance of the earth from the sun, whilst the 
finder showed it sia times the radius of the orbit of the earth, or 581 millions 
of English miles, being of far greater extent than the orbit of Jupiter. And 
assuredly my finder would not show the extreme limit of this phenomenon, 
which manifested on this occasion the common law of all the tails of comets, 
that of taking a direction exactly opposite to the sun, followed by the 
comet from the first day of its appearance after the perihelion. But where 
was its tail before this epoch? will be demanded at each reappearance. 
Is it always lost during the long absence from the sun, and regained by 
the reunion? Where is the force which has each time engendered a body of 
such gigantic dimensions; the:force, in a body so feeble and unshapen as the 
comet, which can project an enormous luminous mass in a short*space of time 
as far as beyond the orbit of Jupiter; to conduct it half round the sun in 
12 30™ 395 for the extreme limit perceived by the finder, a route of 1826 
millions of English miles? That is a celerity of more than a third of a million 
of English miles in a second,—a velocity which surpasses that of light by 
three-fourths! This really pronounces the impossibility of a mechanic nature 
in comets’ tails; it ranges them amongst dynamic appearances. 
However, nothing is as yet explained by this assertion. I consider even 
that only a profound study and perfect knowledge of the works of the late 
Brandes of Breslau, of M. Bessel’s calculations of Halley’s comet before the 
perihelion, and Sir John Herschel’s after this epoch (including the aspect of 
the comet of 22nd January 1836 just like a fixed star), can conduct us to a 
more or less plausible theory of this most highly interesting phenomenon. 
Nevertheless, in such a case it appears to me necessary to endeavour to 
establish a tolerably probable hypothesis, and which may explain a certain 
number of the facts according to the new principle. It will serve, not only 
to show by an example the possibility of the new conjecture, but also to guide 
us, when there is a discordance amongst the observations, to points of view 
more just and more admissible. 
It is now some time since I endeavoured to demonstrate, that, from the 
circumstance of there being no loss of intensity nor refraction from a ray of 
light passing through the volume of a comet, the law of the intensity of 
their light (which as with the planets follows that of the inverse ratio of the 
square of the distance from the sun, but in an abnormal manner that of the 
_ simple distance from the earth) leads us to regard these stars as an accumu- 
_ lation of an immense number of very small bodies, of which each one possesses 
sufficient mass to play the part of a central body, and which all move round 
