40 Dr. Herscitel’s Experiments on the Means 
The weather being as favourable as possible, I saw with 
415,7 the globule No. 10 round at first sight; the magnified 
angle is i' 51", 2. I can see No. 12 steadily round; the angle 
is o",ij2. It is however a mere point, and divisions of it cannot 
be made. 
With a new 10-feet reflector, power 540, the globule No. 10 
is beautifully well defined, and \ of it may be estimated ; the 
angle is o" ,268 ; \ of it is o",i34- 
With the old reflector, and 502,6, I see No. 12 steadily 
round. No. 7, 11, and 13, have met with an accident, and 
could not be observed. 
6 th Experiment zvith illuminated Globules. 
The night being very dark, 8 silver globules, from ,0291 
to ,00596 in diameter were placed on the post, and illuminated 
by a lantern held up against them. 
With 522,7 I saw them all perfectly well, but the small 
quantity of light thrown on them was not sufficient to make 
angular experiments upon them. As objects I saw them as 
easily as in the day time. Probably the phases of the illumi- 
nated disks I saw might be such as the moon would show when 
about 9 or 10 days old. The angle of No. 8, had it been full, 
would have been 0^,51 9. A better way of illumination might 
be contrived. 
SPURIOUS DIAMETERS OF CELESTIAL OBJECTS. 
Observations and Experiments , with Remarks. 
July 17, 1779. With a 7-feet reflector, power 280, I saw 
the body of Arcturus, very round and well defined. I saw 
