n6 Dr. Herschel’s Observations of a Comet , 
its densest light there was an extremely small bright point, 
entirely distinct from the surrounding glare. I examined this 
point with my 20 feet, large 10 feet, common 10 feet, and 
also with a 7 feet .telescope ; and with every one of these in- 
struments I ascertained the reality of its existence. 
At the very first sight of it, I judged it to be much smaller 
than the little planetary disk in the head of the comet of the 
year 1807; but as we are well assured that if any solidity 
resembling that of the planets be contained in the comet, it 
must be looked for in this bright point; I have called it the 
planetary body ; in order to distinguish it from what to the 
naked eye or in small telescopes appeared to be a nucleus, 
but which in fact was this little body with its surrounding light 
or head seen together as one object. 
With a new 10 feet mirror of extraordinary distinctness, I 
examined the bright point every fine evening, and found that 
although its contour was certainly not otherwise than round, 
I could but very seldom perceive it definedly to be so. 
As hitherto I had only used moderate magnifiers from 100 
to 160, because they gave a considerable brightness to the 
point, it occurred to me that higher powers might be required 
to increase its apparent magnitude ; accordingly the 19th of 
October, having prepared magnifiers of 1 69, 240, 300, 400, 
and 6 00, I viewed the bright point successively with these 
powers. 
With 169 it appeared to be about the size of a globule which 
in the morning I had seen in the same telescope and with the 
same magnifier, and which by geometrical calculation sub- 
tended an angle of i",39- 
I suspected that this apparent size of the bright point was 
