PART i] Humidity, Temperature, and Atmospheric Pressure at Dinapore. 257 



38'5 inches has been recorded during 14 years at a meteorological station about eight 

 miles from Dinapore, the large town of Patna. 



Its distribution over the year also is not quite parallel to that of Calcutta, 84*6 

 per cent, of its annual total falling in the wet season — June to September — against 

 74-5 per cent, in Calcutta; but even then the aggregate amount of this season's rainfall 

 remains less than that of Calcutta by 16 inches {vide Table XLV, page 249). 



A comparison of the data regarding Calcutta and Dinapore suggests that conditions 

 of rainfall in a locality (taken in connection with geographical position and geological 

 features) really do exert an important influence on the development and distribution 

 of the cause or causes of cholera. Both stations agree closely in their general physical 

 features, the most important difference lying, as indicated above, in the amount of the 

 rainfall. During the wet season in Dinapore the rainfall is 16 inches less than in 

 Calcutta ; this season at Dinapore contributes 35*7 per cent, of the annual cholera, 

 whilst in Calcutta it only gives 18 per cent. 



As already stated, however, Dinapore may be looked upon as a transition station, 

 for we shall find the contrast becoming more marked as we proceed in a westerly and 

 north-westerly direction. This important difference cannot be set aside on the ground 

 that the statistics do not comprehend a sufficient number of cases, as may, with perfect 

 justice, be said of some of the endemic-area group of stations which we have been 

 obliged to fall back upon. Here we have a large military station which has been 

 occupied during more than 50 years, and furnishing an aggregate of over 3,500 cases 

 of the disease, among a carefully-registered official population. 



This aggregate, moreover, has not been furnished by some one extraordinary 

 epidemic, but is distributed over nearly every year of the period : for example, cases 

 have been recorded during 44 years in April, 43 in May, 42 in August, 40 in June, 38 

 in March, and 34 years in September. It is in January that the disease has occurred 

 least often — 21 times. 



The data in connection with the hygrometric condition of the atmosphere at this 

 station are not so accurate as those which are available regarding Calcutta, still they 

 are probably sufficiently near to enable a fair estimate of its monthly variation to be 

 formed. We have combined the data furnished in the Bengal Meteorological Keport 

 for 1874 with Mr. Blanford's tables for 1875, and thus obtained a monthly mean 

 extending over nine years. 



TABLE XLIX. 



Mean monthly relative humidity of atm^osphere at Dinapore (Patna observations) 

 during nine years ; also Tnean monthly Temperature and atmospheric Pressure. 



