422 Capt. Sabine’s Summary of the Currents experienced 
p ¥Y pp 
tions of a spiral acted upon by the water through which it is 
drawn. The self-registering log was used as a check upon 
the estimated reckoning, and proved the value and efficacy of 
the attention paid to the latter, by its being a’very rare cir- 
cumstance to find a difference between them amounting to a 
mile, in twenty-four hours. The comparison between the ship’s 
run by observation and by reckoning was usually made by 
Capt. Clavering from forenoon to forenoon, and by myself 
from afternoon to afternoon; and the results being each re- 
duced to noon and compared, served for the detection and 
correction of errors, on either side. The table exhibits the 
ship’s true position at noon on each day; the temperature of 
the surface water; and the direction and amount of the dif- 
ference of her position, by observation and by reckoning, from 
noon to noon. On days when the sun was obscured, the di- 
rection of the apparent set is deduced from intervals of forty- 
eight hours instead of twenty-four, but the rate is that due to 
each interval of twenty-four hours. 
"Temp. 
Latitude. | Longitude. A Apparent Set in 
Water each 24 hours. 
From Cape Mount to Cape Three Poiits. 
6° 40! N.}11°48' W.| 84° 
Sun obscured. 83 
4 53 9 04 83 
4 28 8 18 
4 18 6 36 84°8 
4 37 3 48 
ts 53° EF. 32 miles. 
tS. 84 E. 24 
tN. 79 E. 40 
‘N.76 E. 51 
From Lagos to St. Thomas. 
5° 29'N.) 2° 51' BE. | 835 
5 00 2 32 84°5 
S. 45° E. 9 miles. 
bs.64E.17 
4 46 2 49 84 
3 46 o 57 832 iS. 24 E. 16 
Sun obscured. 83 
ts 82 E. 22 
0 36 5 22 | 82°83 
0 16. |\6. 24 82°8 }s. 81 E. 13 
Date. 
