379 
the Land and Sea Rates of Chronometers . 
circumstances, I am willing to think, that the results will not be 
uninteresting to the readers of the Edinburgh Philosophical 
Journal, particularly as they give an undeniable proof that such 
a change actually takes place, and shew the necessity of some 
means, either of preventing it, or of estimating its amount. 
TABLE of the Land and Sea Rates of the Chronometers , supplied to 
his Majesty’s Ship Leven, during her Voyage to the Cape de Verd 
Islands , in the year 1819- 
, 
Particulars of the Times, Places, &c. 
N° 1970, 
Arnold 
Rate. 
N* 498, 
Arnold 
Rate. 
N° 249, 
Harris 
and 
Hatton 
Rate, 
N° 503, 
Arnold 
Rate. 
SR* Lisbon from Jan. 2. to Jan. 28. 1819, 
_ - 
1 1| 3.7 
g 
2.86 
g 
7.74 
SR St Jago from Feb. 8. to Feb. 14. 
l 17.30 
l 
1.98 
or 
to 
5.53 
g 
5.68 
SR Island of Sal, Feb. 28. to Mar. 28. 
l 16.27 
l 
1.25 
& 
6.83 
g 
7.29 
SR Do. Mar. 28, to April 20. 
1 16.99 
l 
0.99 
g 
6,82 
g 
9.8 
SR Quail Island, Apr. 27. to May 4. 
l 17.9 
g 
0.26 
g 
6.34 
O' 
o 
10.39 
SR Do. Apr. 27. to May 12. 
l 17.66 
s 
0.66 
g 
6.55 
g 
9.86 
Mean ship rates from the above, 
l 16.95 
l 
1.47 
g 
6.52 
g 
8.47 
LR -f Madeira, June 20. to July 7. 
l 14.88 
g 
1.27 
g 
2.00 
g 
13.62 
LR Do. July 7. to July 17. 
l 13.90 
g 
3.85 
g 
1.85 
g 
14.85 
LR Do. July 17. to July 28. 
l 13.72 
g 
2.83 
g 
3.64 
g 
13.82 
LR Do. July 28. to Aug. 6. 
l 14.4 
g 
2.73 
g 
2.84 
g 
13.51 
LR Do. Aug. 6. to Aug. 24. 
l 13.85 
g 
2.60 
g 
2.87 
g 
13.15 
LR Do. Aug. 24. to Sept. 1. 
l 14.23 
g 
2.76 
g 
2.26 
g 
12.90 
LR Do. Sept. 1. to Sept. 13. 
l 14.10 
g 
3.20 
g 
3.50 
g 
14.60 
LR Do. Sept. 13. to Sept. 19. 
l 14.10 
S' 
3.50 
g 
3.50 
g 
14.60 
Mean land rates from the above, 
l 14.17 
g 
2.69 
g 
2.75 
g 
13.80 
Difference between the mean Land and 1 
Sea rates, - f 
2.78 
3.22 
3.77 
5.33 
Unfortunately, the maker's rates, with which these chronome- 
ters were measured, and those which they had on their return, 
are not found in the register. 
N. B. It may be proper to observe, that the above land-rates 
were taken by Lieutenant Vidal and myself with an astronomi- 
cal quadrant, at the house of the British Consul. 
* 
J LR Land Rate. 
§ g Gaining Rate. 
-}- SR Ship Rate. 
|| L Losing Rate. 
A BBRF'VI ATIONS. 
