made at Raiatea, one of the Society Islands. 281 



The following table shows the mean temperature of the different 

 months of 1822, by morning, noon, and evening observations : 



I 



Mean annual temperature for 1822 by the table, 78^51. 



It is obvious, however, that, as there was no night observa- 

 tions to balance those made at noon, we must reject the noon 

 observations, in order to obtain the correct mean temperature. 

 We shall thus obtain, — 



Mean temperature for 1822, - - 76°.77 



Mean temperature calculated by Dr Brewster's 



General formula, - - - 76 .11 



*• Error of the formula, 0°.66 



The above result gives for the temperature of the equator 

 80°. 14 differing only 0.3 from the measure obtained in No. 

 XV. p. 67. 



In the 10th Number of this Journal^ p. 370, we have given 

 the mean temperature of Hawai, one of the Sandwich Islands, 

 situated nearly in the same longitude, viz. in 155^° (west 

 long.,) and in a parallel of latitude a little more north than 

 that of Raiatea is south of the equator, as ascertained by 

 the American Missionaries in 1822. The mean temperature 

 of Hawai was 75°.19j the temperature calculated by the For- 

 mula 74°.77, giving an error of only 0°.33. Hence we may 

 conclude that the formula represents very accurately the mean 

 temperature of that part of the globe. 



