of the Equatorial Regions. 137 



If the equatorial temperature under consideration were that 

 of the equatorial zone surrounding the whole globe, and bound- 

 ed by the parallel of '3° north and 3° south, we must first ex- 

 amine the temperature of the equatorial ocean, for there is only 

 one-sixth of the circumference of the globe which in that zone 

 belongs to terra firma. 



But the mean temperature of the ocean between the limits 

 we have mentioned, varies in general between 80°.24, and 82°. 4. 

 I say in general, for we sometimes find between these limits 

 maxima restricted to zones scarcely a degree wide, and 

 whose temperature rises in different longitudes from 83°.7, to 

 84°. 7. I have observed this last temperature, which may be 

 regarded as very high in the Pacific ocean, to the east of the 

 Galapagos Islands, and recently M. Baron Dirckinck of Holm- 

 feldt, a well-informed officer of the Danish navy, who, at my 

 request, made a great number of thermometrical observations, 

 has found (in lat. 2°.5' N., long. 81.°54' W.) almost in the 

 parallel of Punta Guascama, the surface of the water at87 n .l. 

 These maxima do not belong to the equator itself. They oc- 

 cur sometimes to the north, and sometimes to the south of it, 

 and often between the latitude of 2J°, and 6°. The great 

 circle which passes through the points where the waters of the 

 sea are the warmest, cuts the equator at an angle which seems 

 to vary with the sun's declination. In the Atlantic ocean, we 

 may sometimes even pass from the northern to the southern 

 temperate zone, in the zone of the warmest waters, without 

 observing the thermometer rise above 82 Q .4. The maxima are 



According to Perrins - 82° 76' 



Churrucca - 



Quevedo - 



Rodman - 



Dr Davy - 



Mean, 83° 26' 

 The air which rests upon these equatorial waters is from 

 1°.8 to 2°.7, colder than the ocean. It results from these facts, 



measure for the temperature of the equator in America and Asia. This 

 double measure is a necessary result of the isothermal lines being regulated 

 by two poles of maximum cold. — Ed. 



