Temperature of Places in Ceylon. 141 



form of the instrument be employed, the following precautions 

 should be employed, in order to insure a very close approxi- 

 mation to the truth. Take any number of observations, turn- 

 ing the instrument round at each time, and the mean of these 

 will give a result, perhaps as accurate as the nature of the case 

 admits ; at least, it will be sufficiently accurate for all the or- 

 dinary purposes of life. 



When the colours of the flames are different, it is very dif- 

 ficult to ascertain the place of equal illumination. We can, 

 however, as before, find the space over which the instrument 

 moves, before we discover an obvious difference between the 

 illuminated halves of the oiled or white paper. We must then 

 take the middle of this space, which will, even in that difficult 

 case, give us a very good approximation to the truth. But 

 still this, method is of very difficult application, when one of 

 the lights is of a fine white, and the other of a dusky red or 

 blue colour. 



Art. XXXI CONTRIBUTIONS TO METEOROLOGY. 



Communicated by Mr Foggo. 



1. Temperature of Places in Ceylon. * 



1. Point de Galle. — The register for this place was kept from 

 the beginning of March till the end of November 1812, and 

 the thermometer observed three times a-day, viz. 6 A. m. noon, 

 and 6 p.m. The mean temperature, however, is obtained 

 more nearly by taking the average of the two former. The 

 morning observations give for their mean temperature 79-93, 

 and those at noon 83.93, the mean of the two being 81.9. The 

 highest temperature observed was 87°, the lowest 75°; ex- 

 treme range of temperature 12°. The mean temperature at 

 sunset is 81.16, differing from the mean temperature of the 

 day about j of the mean daily range. 



2. Colombo. — Observations were made at 6 a. m., 3 p. m., 

 and 9 p. m. during the year 1812, excepting the month of 

 December. The mean temperature of 6 a. m. is 79.61, of 



* The registers from which these temperatures are deduced, were kind- 

 ly communicated to the Editor hy Henry Harvey, Esq. 



