METEOROLOGY. 



the observations were all of them made at noon : the greatest 

 variation to be found in the table, of the temperature of any one 

 month, is 8°. 5, in that of January 1791, when the heats pre- 

 vailed ; and the least variation is 3°. 5, in the month of July, 

 belonging to the mild season. In London, in the above year, 

 the greatest variation in the observations of any one month, 

 made at two in the afternoon, is 28°, in the month of June, that 

 variation being six degrees more considerable than the one re- 

 sulting from the observations of the whole year in Lima ; and 

 the least variation is 16% in the month of March. But a still 

 more striking fa6l, relative to the changes of the temperature 

 of the air, in establishing a comparison on that point between 

 the two capitals, is the following : that on one particular day, 

 the 1 3th of September, between seven in the morning and two^ 

 in the afternoon, a space of seven hours only, there was in 

 London a variation of 21°, the mercury having risen from 52° 

 to 73% within 1° of its complete annual range in Lima. The 

 greatest variation of the degree of atmospherical heat, between 

 any two consecutive days at Lima, was 5°. 5, namely, between 

 the 27th of November, when the mercury stood at 7 2°. 5, and 

 the 28th, when it sunk to 67°. In London, the greatest vari- 

 ation in the observations made in the afternoon, was, under the 

 same circumstances, 14°, between the 7th and 8th of June, 

 when the mercury sunk from 80° to 66° ; and between the 22d 

 and 23d of December, when it rose from 34 to 48. The mean 

 degree of temperature of the coolest month at Lima, Septem- 

 ber, was 64°. 5, and comes the nearest to that of the same 

 month of the same year in London, the latter having, agree- 

 ably to the observations of the afternoon, been 6()°.(). The mean 

 degree of temperature of the month of March, the hottest which 



occurred 



