ESTrMATION OF MEAN TEMPERATURE, 



17 



the difference would be material. At the equator, the mean meridian altitude of the sun, 

 instead of being 90°, is but 76° 20' ; and at the pole, instead of being- 0°, it is to be con- 

 sidered 13° 40', since aside from refraction the sun exerts no heating power when below 

 tlie horizon. In calculating the temperatures of Havana, Cumana and Quito, which lie 

 in tlie torrid zone, I corrected the formula as here suggested. 



After these preliminary investigations, I proceeded to examine the climate of the State, 

 in reference to the mean temperature, the extremes of heat and cold, the length and 

 forwardness of the seasons, and the progress of vegetation. 



In estimating the mean temperature of the several localities where observations had 

 been taken, I took it as given in the Regents' Reports for all places where the period 

 of observation amounted to ten years or more. For all others, I compared the mean tem- 

 perature on the years observed, with the mean for the State on the same years, and the 

 latter with its mean temperature for the whole seventeen years since the observations under 

 the instructions of the Regents were commenced. The mean of the observed temperatures 

 [Agricultural Report.] 3 



