PHILOSOPHICAL 
TRANSACTIONS. 
VIII. Observations on the two lately discovered celestial Bodies. 
By William Herschel, LL. D. F. R. S. 
Read May 6 , 1802. 
In my early account of the moving star discovered by Mr. 
Piazzi, I have already shewn that it is of a remarkably small 
size, deviating much from that of all the primary planets * 
It was not my intention to rest satisfied with an estimation 
of the diameter of this curious object, obtained by comparing it 
with the Georgian planet, and, having now been very successful 
in the application of the lucid disk micrometer, I shall relate 
the result of my investigations. 
But the very interesting discovery of Dr. Olbers having 
introduced another moving star to our knowledge, I have 
extended my researches to the magnitude, and physical con- 
struction, of that also. Its very particular nature, which, from 
the observations I shall relate, appears to be rather cometary 
* By comparing its apparent disk with that of the Georg.ak planet, it was 
— thi “ ‘ he feal dia ‘ WtCr ° f tWs nEW Star C01!ld not amount t0 Phs of that of 
MDCCCII, 
Ff 
