S46 Mr Black on the Climate 



descended below 54.6,° which is 2" above the mean annual tempe- 

 rature at Gosport, as observed by Dr Burney *. This extreme 

 montJi\ly temperature of 54.6° in February 1824, was attributed 

 to the strong northerly winds which for ten days prevailed at 

 Smyrna ; and as the average for the same season in the other 

 two years was nearly two degrees higher, I should consider that 

 they best expressed the corresponding temperature in the two 

 years in which my daily register was not kept. The highest 

 range observed at noon was 86°, which was off Algiers, in Au- 

 gust 1824, and the lowest was 41°, at Smyrna, in the evening 

 at eight, in January 1827. The range of the summer months 

 never exceeded 11°, while that of the other months was often as 

 much as 25°. For three months after the summer solstice, the 

 heat on board was steady above 76° ; and when the winds at this 

 season are scanty, the thermometer is sometimes above 90° on 

 shore. If it were not that the great heats of summer exhaust 

 the sources of humidity, the atmosphere would be felt the moist- 

 est during the greatest heat. We should, also, have the hea- 

 viest dews at night ; but the reverberation from the heated sur- 

 face of the earth often keeps the vapour suspended through the 

 night, though clouds may be precipitated in the 'higher and cooler 

 regions. 



Besides the characteristic temperature of the season, the heat 

 at any place is moreover greatly affected by the winds at the 

 time; thus, the westerly winds will not disturb much the regu- 

 lar increase or fall for the season, and the easterlv but little ; 

 while the winds from the north, before the melting of the snows 

 on the Appenines and on the Chain of Pindus, in May and 

 June, will lower the temperature many degrees on the south 

 coasts of Italy and the Morea. The south and south-east winds 

 will, on the other hand, as remarkably elevate the thermometer ; 

 especially if they have blown steadily for a few days, and not 

 over a widely intervening extent of sea. The effect of warm 

 winds, immediately succeeding those from the north or a cold 

 quarter, has often been observed to be productive of severe ca- 



• From registering thermometers kept for several years at London, it ap- 

 pears as calculated in the British Almanac for 1828, that the mean tempera- 

 ture of the year, by night and day, is 49°4. The mean dailt/ temperature of 

 the year in the south of Scotland has been verified to be about 54", and that 

 of Devonshire to be a degree or two higher.— J. B. 



