AND METEOROLOGY OF DUKHUN. 179 



latter 28087 inches, thermometer 75°4. The minimum height in the year and the 

 mean monthly minimum, in like manner, both occur in the same month, July, the 

 former being- 27'570 inches, thermometer 75°, and the latter 277666, thermometer 

 76°'95. The annual range of the barometer, therefore, amounted only to "6720 ; 

 and the difference of the thermometer at the extreme periods was l°-4 ; the greatest 

 monthly range, -3710, was in November ; the difference of the attached thermometer 

 at the extreme periods was 10°'2 ; the smallest monthly range of -2170 was in Au- 

 gust ; the difference of the attached thermometer at the extreme periods being 0°'5. 

 In 1827 the barometer ranged during six months whilst I was stationary, only -5103. 

 In seven months in 1828 it was -3656, and for seven months in 1829 it was -4867; 

 and in no instance did a range of eight tenths of an inch come under my observa- 

 tion, even in comparing the maximum of one year with the minimum of another. 

 Whilst in England, at Edmonton and Cheltenham, in 1827, the extreme range of the 

 barometer was respectively 1*88 inch and 175 inch. In 1828, at Edmonton, Chel- 

 tenham, and Weycomb, the range was 1*44 inch, 1*41 inch, and 1-61 inch respectively. 

 An inspection of my tables will show that in four years, in the five monsoon montJis, 

 from the maximum height 28' 1343 inches, thermometer 76°'4 in October 1827, to the 

 minimum height of 27'570, thermometer 75° in July 1830, the range amounted only 

 to "5643, difference of thermometer attached 1°'4. In looking over Mr. Goldingham's 

 tables for twenty-one years at Madras, the greatest annual range (with a solitary ex- 

 ception of 1-430 inch in a terrific hurricane in May 1820,) amounted to '9640 in 1818, 

 and the greatest monthly range was in October of the same year 7940 ; the smallest 

 annual range was '4620 in 1814; in fact, the annual range very rarely exceeded 

 six tenths of an inch. 



I found the mean monthly pressure of the atmosphere at its maximum in the 

 coldest months, December and January ; it gradually diminished until July or Au- 

 gust, the most damp months ; and gradually increased again until the cold months. 

 Mr. Goldingham's means of twenty-one years give nearly the same results ; the maxi- 

 mum pressure 30*085 inches, thermometer 75°' 1 68, being in December or January; 

 it then diminishes until May, June, and July, the mean height of the barometer, 

 29*860, thermometer 86°*907, being nearly the same in those months. But it is to 

 be remarked, that two of these months, which atPoona are the most damp, at Madras 

 are the hottest of the year : the minimum pressure, therefore, was as independent of 

 moisture at Madras, as it was independent of extreme heat at Poona. From July the 

 pressure gradually increases as at Poona, until December or January. Three years' 

 observations at Calcutta indicate the same alternations. The barometer is highest in 

 January, 30*0225 inches, and lowest in June, 29*5155 inches. At the Havannah the 

 mean of three years gives a maximum pressure in January and a minimum in Sep- 

 tember. Opposed to these indications of uniformity of atmospheric action over a 

 wide range of latitude and longitude, M. Boussingault found the maximum height 

 of the barometer at Bogota for one year greatest in June and July, and least in Decem- 



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