6 1 
of the Sun and fixed Stars. 
This throws a mystery over their destination, which seems to 
place them in the allegorical view of tools, probably designed 
for some salutary purposes to be wrought by them ; and, whe- 
ther the restoration of what is lost to the sun by the emission 
of light, the possibility of which ,we haye been mentioning 
above, may not be one of these purposes, I shall not presume to 
determine. The motion of the comet discovered by Mr. Mes- 
sier in June, 1770; plainly indicated how much its orbit was 
liable to be changed, by the perturbations of the planets ; 
from which, and the little agreement that can be found be- 
tween the elements of the orbits of all the comets that have 
been observed, it appears clearly that they may be directed to 
carry their salutary influence to any part of the heavens. 
My hypothesis, however, as before observed, does not lay 
me under any obligation to explain how the sun can sustain 
the waste of light, nor to shew that it will sustain it for ever ; 
and I should also remark that, as in the analogy of generating 
clouds I merely allude to their production as owing to a de- 
composition of some of the elastic fluids of our atmosphere, 
that analogy, which firmly rests upon the fact, will not be less 
to my purpose to whatever cause these clouds may owe their 
origin. It is the same with the lucid clouds, if I may so call 
them, of the sun. They plainly exist, because we see them ; 
the manner, of their being generated may remain an hypothe- 
sis ; and mine, t il a ; better can be proposed, may stand good ; 
but whether it does or not, the consequences I am going to 
draw from what has been said will not be affected by it. 
Before I proceed, I shall only point out, that according to 
the above theory, a dark spot in the sun is a place in its atmo^ 
sphere which happens to be free from luminous decomposi- 
