PART II.] Chemical Constituents of Delhi Water-supply. 415 



words, as, so far as our own observations went, there was nothing to be detected which 

 could in any way be connected with the production of any cutaneous affection akin to 

 that under consideration. 



The chemical examination, however, was suggestive. Bearing in mind what has 

 already been stated regarding the geographical distribution of " sores " in India, it may 

 be reasonably inferred that the organic impurities, as such, may be set aside, for the 

 water of Delhi assuredly is by no means exceptionally bad in this respect. On the 

 contrary, the quantity of unoxidised organic matter is, in most instances, small in the 

 water supplies most resorted to by the population, and not to be compared with the 

 large quantities commonly presented in the water tanks of places such as Calcutta and 

 other cities in the Lower Provinces, where Oriental sores are practically unknown. 

 Of this we satisfied ourselves by means of special distillations of numerous samples of 

 water in accordance with the principles laid down by Messrs. Wanklyn and Chapman, 

 the details of which, however, need not be recorded here, seeing that our object is not to 

 report upon the local water-supply. 



The results of the oxidation of organic substances in the form of nitrates and nitrites 

 have been shown by all our analyses to be present in very large quantities, and are 

 associated with a marked quantity of chlorides. So saline is the water in certain wells, 

 that it cannot be even employed to water plants. 



So far the result of our analyses has been substantially in accordance with those 

 of former observers ; but here the agreement ceases, for, according to them, the water 

 of the Delhi wells presented no striking peculiarity in regard to hardness, whereas 

 we found the waters as a general rule excessively hard, and in some cases almost 

 unprecedentedly so. 



We append a table giving the estimates of the " total " hardness, the " permanent " 

 hardness, and the amount of chlorine; the last-named calculated in grains per gallon 

 of chloride of sodium in a number of the wells in and around Delhi, as well as of a 

 few samples of water (Nos. 23 to 28) which we collected in three towns in the Delhi 

 district, at a distance of 10 to 25 miles from the city itself. 



As is well known, the process generally adopted (Clarke's) for determining the 

 hardness of a water may very readily give rise to fallacy owing to the presence of 

 magnesian salts, unless special attention is devoted to the point ; and it is doubtless 

 due to this, in a great measure, that the hardness of the water has been so largely 

 under-estimated. We believe that our figures may be accepted as correct ; they give 

 the result of, in most instances, two or three distinct determinations specially directed 

 for elucidating this very question. 



These analyses were conducted towards the end of the dry season, when the waters 

 were doubtless more extensively impregnated with salts than after the rainy season. 

 With the intention of definitely satisfying ourselves as to the extent of the variation, 

 we obtained (by the kind assistance of the Engineer to the Municipality, Mr. A. J. 

 Devon) four more samples of water collected shortly after the cessation of the rains. 



