PART I.] The Theory in Relation to Rivers in India. 45 



made of the quality of water which is sinking, and the results were by no means 

 unfavourable — in some cases the water was even found to be more pure. As far. 

 as the tanks in Calcutta are concerned, I cannot bear testimony to the observations 

 of Pettenkofer in this matter, because the percentage of organic matter has been 

 greater when the tanks were low than when in the contrary condition ; concerning 

 the quality of water in deep wells at various heights, I possess no data. 



The foregoing remarks will, I trust, be found to present a tolerably clear exposi- 

 tion of the theory concerning the relation said to exist between the spread of 

 cholera and the state of the ground water. 



I now proceed, in as few words as possible, to give an account of my visit to 

 the places affected with cholera in the North- Western Provinces during the severe 

 epidemic of last autumn (1869). 



ALLAHABAD. 



I arrived at Allahabad towards the end of August, 1869, in accordance with the 

 instructions I had received, in order to accompany the Sanitary Commissioner with 

 the Grovernment of India in his tour through the cholera-affected districts, and thus 

 be able to avail myself of his advice and direction. 



Seeing that our visits to the various places, to be hereafter alluded to, were 

 necessarily of short duration, it was impossible for me to obtain more than a very 

 superficial knowledge of the geography of a place extending over such a wide area as 

 Allahabad does. 



Situated in the angle formed by the junction of two rivers, the Granges and 

 Jumna, it was thought not improbable that the high or low condition of these 

 rivers might materially affect the level of water in the wells, seeing that many acres 

 of land are swamped during the rains, the station being almost surrounded by water, 

 as a glance at the accompanying map will show. 



This, however, was ascertained by Dr. Bow not to be the case, at least as far as 

 the Jumna was concerned, the water in the wells being nearly thirty feet below the 

 level of the surface of the Jumna. 



The average depth of the wells from the surface, as examined by Dr. Chalmers and 

 myself, was found to be from fifty to sixty-five feet. The average variation in the 

 level of the water between the dry and the wet season is about ten feet, whereas 

 the Jumna varies to the extent of thirty feet or more under ordinary circumstances ; 

 nor does the alteration in the water-level of the one correspond with the variation 

 in the other, and a consecutive fall of rain of twelve inches will not raise the 

 level of the water to the extent of more than one or two ; a great portion, 

 doubtless, finding its way into the river before getting into wells, especially after the 

 first falls of rain, when the ground does not permit of such free percolation. It 

 cannot, therefore, be said that the amount of subsoil water at Allahabad is materially 

 affected by the rivers which bound it on either side ; nor will it be safe to judge 



