280 Mr Threlkeld's Therrnometrical Observations 



gregate mean temperatures in the preceding table should be 

 diminished by about fths of a degree. 



By examining the preceding observations, it appears that 

 at all the stations the time of the evening at which the mean 

 temperature occurs is before 9'' p. m. and after T' a. m. 



If we compute the mean temperature of a point correspond- 

 mg with the mean position of all the above stations by means 

 of Dr Brewster's General Formula for the Western Hemi- 

 sphere of the globe, we shall have 



Mean temperature by Formula, - 54°80 



Do. observed, - - 56 52 



Difference, - - 1°72 



The observed mean temperature ought, from what has been 

 above stated, to be diminished about fths of a degree ; and it 

 requires also to be increased, in order to reduce the mean tem- 

 perature of the elevated stations to the level of the sea ; but as 

 the elevations of several of the stations are not known, it is out 

 of our power to apply the requisite correction. 



Art. XII. — Thermometrical Observations made at Raiatea, 

 one of the Society Islands^ hi 182^. By the Rev. L. E. 

 Threlkeld.* 



The following series of very valuable observations were made 

 in 1822, by the Rev. L. E. Threlkeld, one of the missionaries 

 at Raiatea or UHetea, one of the Society Islands. It is si- 

 tuated in west long. 151°30/, and south latitude 16°40'. 



The tide at Raiatea, which rises about two feet, is never at any 

 time affected by the moon, and is always highest at 12 o'clock. 



Although the quantity of rain which fell in this island was 

 not measured, yet the number of rainy days is marked in the 

 Journal, and are as follows : — 



January, 18 May 



February, 20 June, 



March, 20 July, 



April, 21 August, 



Number of rainy days, 222 

 • The Etlitoi:.has been indebted for these observations to James Dunlop, Esq. 

 I From the 22d till the 31st of July no account of the rainy days was kept. 



