Dr. Tiarks’ account of 
3 % 
Difference of Longitude between Dover and Falmouth , by 
twenty-four Chronometers . 
First Mode of Interpolation. 
Second Mode of Interpolation. 
Observations. Mean Results. 
Observations. Mean Results. 
2 and 1.3 
h / „ 
. . . O 25 28.35I 
2 and all Dover Obs. c 
/ n 
25 28.283 
3 and 2.4 
. . . 28.436 
3 and all Ealmouth Obs. 
. . 28.722 
4 and 3.5 
29.152 
4 and all Dover Obs. . 
. . 28.942 
5 and 4.7 
. . . . 27.104 
5 and all Falmouth Obs. 
. . 28.346 
Mean 
0 25 28.261 
Mean . . . . c 
3 25 2 8 -573 
Difference 
of Longitude between Portsmouth and 
Falmouth , 
by twenty-six 
Chronometers. 
First Mode of Interpolation. 
Second Mode of Interpolation. 
Observations. 
Mean Results. 
Observations. 
Mean Results. 
6 and 4.7 
h / » 
. . . . O 15 42.560 
6 and all Falmouth Obs. 
h 1 „ 
0 15 43.680 
7 and 6.8 
45- 8 45 
7 and all Portsmouth Obs. 
. . 46.362 
8 and 7.9 
46.710 
8 and all Falmouth Obs. 
• • 46.73* 
9 and 8.10 
45-534 
9 and all Portsmouth Obs. 
46.622 
Mean 
0 15 45.162 
Mean 
0 15 45.849 
Taking the mean of all results, we have finally for the 
difference of longitude between Dover and Falmouth o h 25/ 
28". 417. The longitudes of the Survey, (applying the reduc- 
tion to my station at Dover, which was nearly o".i east of 
that of the Survey) will give the same difference o h 25' 23". 5. 
The difference of longitude of Portsmouth Observatory, near 
which I observed, and Falmouth, is by the Survey o h 
Although the observations from which the above given re- 
sults for the same difference of longitude are derived, were 
made under less favourable circumstances and at greater in- 
tervals, (especially the first) and therefore do not agree so 
