of ascertaining the Magnitude of small celestial Bodies. 59 
larger, equal to that of the equal, and larger than that of the 
smaller star. The gradual difference between the three stars 
is exceedingly small. 
“ With 496,3, and the air uncommonly pure and calm, I see 
“ so well that I am certain the disk, if it be not a spurious one, 
“ is less than one of the smallest globules I saw this morning 
“ in the tree.” 
The diameter of this globule was ,02. It subtended an angle 
of o'', 42 9, and was of sealing-wax ; had it been a silver one, 
it would have been still more visible. 
With 879,4. All comparative magnitudes of the asteroid and 
stars, remain as with 496,3. 
I see the minute double star q Ophiuchi * in high perfection, 
which proves that the air is clear, and the telescope in good 
order. 
The asteroid being now in the meridian, and the air very 
pure, I think the comparative diameter is a little larger than 
that of an equal star, and its light also differs from star-light. 
Its apparent magnitude, however, can hardly be equal to that 
of the smallest globule I saw this morning. This globule 
measured ,01358, and at the distance of 9620,4 inches sub- 
tended an angle of o",2i4. 
When I viewed the asteroid with 879,4 I found more hazi- 
ness than an equal star would have given : but this I ascribe 
to want of light. What I call an equal star, is one that in an 
achromatic finder appears of equal light. 
Oct. 7. Mr. Harding's asteroid has continued its retrograde 
motion. The weather is not clear enough to allow the use of 
high powers. 
* See Cat. of double Stars, I. 87. 
I 2 
