3 66 Capt. Kater/s experiments for determining the variation 
Rate of the clock at Leith Fort, ist Series. (Gaining.) 
Stars. 
From 
August 31 , 
to Sept. 2. 
From 
August 31 , 
to Sept. 4 . 
Fro m 
Sept. Q, to 
Sept. 4. 
From 
Sept. 2, to 5 . 
From 
Sept. 2, to 6 . 
From 
Sept. 5 , to 6 
s. 
S. 
S. 
s. 
s. 
S. 
The Sun 
— 
— 
— 
27,04 
27,69 
29,64 
a. Capricorni 
' 25,56 
26,26 
26,95 
— 
— 
— 
e Aquarii . 
— 

27.07 
— 
— 
— 
a. Equulei . 
2 5>55 
26,28 
27,02 
— 
— 
— 
|3 Aquarii 
2 5.83 
26,34 
26,85 
— 
— 
— 
e Peg a si . 
— 
26,33 
— 
— 
— 
— 
0 Aquarii . 
25.75 
26,37 
27,00 
— 
— 
— 
y Aquarii . 
— 
26,41 
— 
— 
— 
— 
z Aquarii . 
— 
26,38 
— 

— 
— 
n Aquarii . 
— 
— 
— 
— 
— 
— i 
| Pegasi . 
— 
— 
27,09 
— 
— 
— 
Mean by the { 
Stars 5 
25,67 
26,34 
27,00 
— 
— 
— 
Mean by the 1 
27,69 
29,64 
Sun i 
27,04 
The steeple of Leith church, being very conveniently situ- 
ated for the purpose, I was anxious to ascertain with what 
degree of precision the rate of the clock might be obtained, 
by observing the disappearance of stars behind the steeple, a 
method which I understand was employed by M. Biot, in his 
late laborious experiments on the length of the pendulum, and 
which seems capable of great accuracy. For this purpose I 
used a powerful achromatic telescope, with which I was 
favoured by Mr. Jardine from the observatory. The tele- 
scope was placed so as to rest against the door way of the 
room which contained the clock, and was directed towards the 
side of the steeple. On the evening of the 30th August, I ob- 
tained observations of the time of the disappearance of several 
* 
stars, and on the 6th of September, two of these stars were 
again observed, but the rest were not visible. By these stars, 
