of the Equatorial Regions. 143 



ly five days. Near the tropics, for example at the Havanna, 

 (lat. 23°29,) the sun employs twenty-four days to describe a 

 degree on each side of the zenith ; under the equator it em- 

 ploys only five days. At Paris, lat. 48° 5CK, where the sun 

 descends to the winter solstice, as far as 17° 42' ; the solstitial 

 height in summer is 64°38\ The sun is consequently from 

 the 1st of May till the 12th August, during the interval of 

 103 days, or 1422 hours, as high at Paris as at Cumana at an- 

 other epoch in the year. In comparing Paris to the Havanna, 

 we find, in the first place, from the 26th March to the 17th 

 September, during 175 days, or 2407 hours, the sun as high 

 as it is in any other season under the tropic of Cancer. But 

 in this interval of 175 days, the warmest month (July) has, 

 from the register kept in the royal observatory from 180b' to 

 1820, a mean temperature of 65°. 48, whilst at Cumana, and 

 at the Havanna, where the sun descends, in the first place, to 

 56°5\ in the second, to 43°23', the coldest month still gives, 

 in spite of the long nights at Cumana, 79°.16, and at the Ha- 

 vanna 70°. 16 of mean heat. Under all zones, the temperature 

 of a part of the year is modified by the temperature of the 

 seasons which precede it. Under the tropics the diminution 

 of the temperatures is very inconsiderable, because the earth 

 has received in the foregoing months a mass of mean heat, 

 which is equivalent at Cumana to 80°.6, and at Havanna to 



From the considerations which I have now explained, it 

 does not appear to me probable that the equatorial tempera- 

 ture ever reaches 84°.56, as is supposed by the learned and 

 estimable author of the Memoir on Astronomical Refractions. 

 Father Beza, who was the first traveller who recommended 

 observations at the coldest and warmest hours of the day, be- 

 lieved that he had found in 1686 and 1699, in comparing 

 Siam, Malacca, and Batavia, " that the heat is not greater 

 under the equator than under 14° of latitude." I am of opi- 

 nion that there is a difference, but that it is very small, and 

 masked by the effect of so many causes, which act simulta- 

 neously on the mean temperature of a place. The observa- 

 tions hitherto collected do not afford us any measure of a pro- 



