196 LIEUT.-COLONEL SYKES ON THE ATMOSPHERIC TIDES 



surgeon in the city of Abmednuggur, (exclusive of losses from spasmodic cholera,) 

 found the casualties in that city to be only 1*82 per cent., or 1 in 55*1 persons ; and 

 including cholera, 2'48 per cent., or 1 in 40*2 persons. Dr. Lawrence, in charge of 

 a regiment of natives 1000 strong, lost only 0*85 parts of an integer per cent., or 

 about 5 men in every 600 per annum during the years the regiment was in Dukhun ! 

 In conclusion, it may be desirable to give an abstract of the facts established, and 

 the principal matters noticed in the preceding paper, viz. the entire removal of Hum- 

 boldt's doubts, founded on the authority of Horsburgh, of the suspension of the at- 

 mospheric tides during the monsoon in Western India : the existence of four atmo- 

 spheric tides in the twenty-four hours, two diurnal and two nocturnal, each consist- 

 ing of a maximum and a minimum tide : the occurrence of these tides within the same 

 limit hours as in America and Europe : the greatest mean diurnal oscillations taking 

 place in the coldest months, and the smallest tides in the damp months, of the mon- 

 soon in Dukhun ; whilst at Madras, the smallest oscillations are in the hottest 

 months, and in Europe it is supposed the smallest oscillations are in the coldest 

 months : the regular diurnal and nocturnal occurrence of the tides without a single 

 case of intervention, whatever the thermometric or hygrometric indications might 

 be, or whatever the state of the weather, storms and hurricanes even only modifying 

 and not interrupting them : the anomalous fact of the mean diurnal oscillations be- 

 ing greater at Poona at 1823 feet, than at the level of the sea in a lower latitude at 

 Madras : the fact of the diurnal tides at a higher elevation than Poona being less, 

 whilst the nocturnal tides were greater than at Poona : the seasons apparently not 

 affecting the limit hours of the tides : the maximum mean pressure of the atmosphere 

 being greatest in December or January, then gradually diminishing until July or Au- 

 gust, and subsequently increasing to the coldest months : the very trifling diurnal and 

 annual oscillations compared with those of extra-tropical climates : the annual range 

 of the thermometer less in Dukhun than in Europe, but the diurnal range much 

 greater : the maximum mean temperature in April or May, gradually declining until 

 December or January : the observed mean temperature of places on the continent of 

 India much higher than the calculated mean temperature agreeably to Meyer's for- 

 mula: annual mean dewing-point higher at 9^ SO"" than at sunrise or 4 p.m. : highest 

 dewing-points in the monsoon, and lowest in the cold months : considerable differ- 

 ence in the dewing-points within very short distances : remarkable contrast between 

 the dewing-points in Bombay and Dukhun : dew frequently local and occurring under 

 anomalous circumstances : rain in Dukhun only 28 per cent, of the fall in Bombay, 

 ninety or a hundred miles to the westward r winds principally from the westerly and 

 easterly points, rarely from the northerly or southerly points, and the absence of 

 wind frequent : electricity very abundant under certain circumstances : fogs rare, and 

 always dissipated by 9 — 10 a.m. : very remarkable circular and also white rainbows : 

 solar radiation very great : and finally, I must not omit to notice the singular opa- 

 city of the atmosphere in the hot weather, and the occurrence of the mirage. 



