~ 
338 Capt. Sabine on the Influence of-the Vicinity 
in December, the mercury in the barometer was lower.than it 
had been known for 35 years before *. 
On leaving the Cape Verd Islands, the Iphigenia proceeded 
to make the continent of Africa at Cape Verd. ‘The distance 
between the Cape and the Islands is about 400 miles, both be- 
ing in the same parallel of latitude. ‘This passage afforded an 
interesting opportunity of observing on the approach to land, 
the influence of its vicinity on the temperature of the sea. The 
general temperature of the surface in that parallel and at that 
season may be considered 71°-7, the observations made at sun- 
rise, noon, and sunset, in the first 350 miles of the passage, va- 
rying from 71° to 72°-4: but at sunrise on the 31st of January, 
being then at the distance of 26 miles west of Cape Verd, with 
no land as yet in sight, the surface-water had lowered to 69°°6. 
On approaching nearer it progressively diminished, until at 
* The following description of this very remarkable winter is extracted 
from Mr. Daniell’s Essay on the Climate of London (Meteorological Essays, 
London 1823, pages 297 and 298), and becomes highly curious when viewed 
in connexion with the unusual temperature of the ocean in the direction 
from which the principal winds proceeded. 
“« November 1821, differed from the mean, and from both the preceding 
years, in avery extraordinary way. The average temperature was 5° above 
the usual amount, and although its dryness was in excess,” [the relative 
dryness, in consequence of the increased temperature] “ the quantity of rain 
exceeded the mean quantity by one half. The barometer on the whole 
was not below the mean. All the low lands were flooded, and the sowing 
of wheat very much interrupted by the wet. 
“In December, the quantity of rain was very nearly double its usual 
amount. The barometer averaged considerably below the mean, and de- 
scended lower than had been known for 35 years. Its range was from 
30:27 inches to 28:12 inches. The temperature was still high for the sea- 
son, and the weather continued, as in the last month, in an uninterrupted 
course of wind and rain; the former often approaching to an hurricane, 
and the latter inundating all the low grounds. The water-sodden state of 
the soil, in many parts, prevented wheat sowing, cr fallowing. the land at 
the regular season. The mild temperature pushed forward all the early 
sown wheats to an height and luxuriance scarcely ever before witnessed. 
The grass, and every green production, increased in an equal proportion. 
January 1822. This mest extraordinary season still continued above the 
mean temperature, but the rain, as if exhausted in the preceding month, 
fell much below the usual quantity in this. There was not one day on 
which the frost lasted during the twenty-four hours. 
“ Serious apprehensions were entertained lest the wheats, drawn up as 
they had been by warm and moist weather, without the slightest check from 
frost, should be exhausted by excessive vegetation, and ultimately be more 
productive in straw than corn. 
“The month of February, still five degrees above the mean temperature, 
ended a winter which has never been paralleled.” 
It would not be difficult to trace in detail, each of the effects described 
in the preceding extract, to the cause which has been thus placed in con- 
nexion with them. 
one 
