Page:The Present State of Peru.djvu/455

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METEOROLOGY.
399

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 prevailed; 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 resulting 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 fact, 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 13th 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 72°.5, and the 28th, when it sunk to 67°. In London, the greatest variation 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, September, was 64°.5, and comes the nearest to that of the same month of the same year in London, the latter having, agreeably to the observations of the afternoon, been 69°.9. The mean degree of temperature of the month of March, the hottest which
occurred