350 Leiter from Von HumhoIJt to LalanJe. 



eertdin in regard to my longitudes than is ufual, the fmall 

 chart in which I intend to make known the refiiU of thefe 

 txperimcnts- will be interelting. In the latitude of 17° and 

 'i8' north, th<^re is a zone in the fea between Africa and the 

 Well Indies, where, without an extraordinary* current pre- 

 vailing, the water is denCcr than under a lefi latitude. The 

 following are fome of my refults refpefting the temperature 

 of the fea water : 



This letter was written at Cumana, but for want of a 

 proper opportunity 1 was obliged to bring it with me to this 

 large capital of the province of Caraccas, w hich is fituated 

 in a fertile valley abounding with cacao, cotton, and cofl'ee, 

 2400 feet above the level of the fea, and in a climate per- 

 ,fe6llv fimilar to that of Europe. The thermomefer in the 

 nicht-time falls to ii=, and in t^he day never rifes above 17" 



The cloudy weather, which here daily follows the fun's 

 paffage over the meridian, makes the obfervation of corre- 

 fponding altitudes very difficult and uncertain, as the afler- 

 .noon obfervation is often loft. The ckiudy wcalhcf after the 

 earthquake of Cumana deprived me of an opportunity of ob- 

 ferving the immerfions of the fecond fa lellite of Jupiter on 

 the 2d and 9th of November. I lliall here give you the prin- 



cipaJ 



