356 Capt. Kater/s experiments for determining the variation 
done but justice, and has left me nothing to add, but- that I 
experienced from him every attention that could contribute to 
my personal comfort, and every anxious exertion that could 
tend to forward the enquiry in which I was engaged. 
Operations at Portsoy. 
On the first of August I arrived at Portsoy, near to which 
is Cowhythe, the next station of the trigonometrical survey, 
which I proposed to connect with my observations, and after 
much search fora place suited to my experiments, was kindly 
favoured by the Rev. Mr. Grant, with the use of his school- 
house, which was perfectly adapted to the purpose, the walls 
being thick, and firmly built of serpentine. I was also so 
fortunate as to obtain accommodations for myself, at a house 
belonging to a gentleman of the name of Watson, immedi- 
ately adjoining the school-house, and whose garden afforded 
an excellent situation for the transit instrument. 
On the 5th August I commenced the observations detailed 
in the Appendix, from which is extracted the following table 
for obtaining the rate of the clock : 
Transits observed at Portsoy. 1st Series. 
Stars. 
August 5 . 
August 6. 
August 7 . 
August 8. 
August 10. 
August 11. 
August 12 . 
h. m. s. 
h. m. s. 
h. m. s. 
h. m. s. 
h. m. s. 
h. m. s. 
h. m. s. 
The Sun 
« • • 
0.14.41,62 
0.15. 7,95 
0.15.36,56 
0.16.38,83 
• • • 
0.17.42,63 
Arcturus 
0 • 
5.1 1.20,5 1 
5. 446,51 
. 
4.58.16,63 
a Ophiuchi 
• 
8.36.42,60 
8.30. 1,45 
8.23 28,67 
8.20.13,59 
8. 16.58,52 
t Ophiuchi 
9. 2.35,99 
8.52,29,70 
8.45.56,85 
8.42.41,94 
8. 39.26,94 
d Serpentis 
9.25.25,99 
9.15.19,73 
9. 8.46,76 
9 5-3 2 >°3 
9. 2.17,04 
a Lyrae 
g. 44. 16,2© 
9.34.10,19 
9- 2 7-37> 34 
9.24.22,52 
9.21. 7,43 
a 
. 
. . . 
9.53.22,62 
9 50. 7,82 
9.46.52,91 
b 
10 16.29,86 
. . . 
9.59.51,24 
9.56.36,52 
9 53- 2I >6i 
^ Aquilae 
10.38.33,58 
10.15.25,11 
a Aquilae 
10.55.13,62 
10.45. 8,14 
10.38.35,49 
10.35.20,47 
10.32. 5,33 
From the above data the following rates of the clock were 
obtained, in the manner which has been before fully particu- 
larized. 
