40 CLIMATE AND RESOURCES OF 



It is probable that in former times these jheels were lakes 

 of open water fringed with bulrushes and other aquatic plants, 

 that they have been gradually getting shallower by silt, the 

 dust deposited in them by dust-storms, and the decaying of 

 the vegetation which was grown in them, and are now 

 becoming the sources of disease, in proportion to the greater 

 extent of their beds exposed to the influence of the sun's 

 heat. As sheets of open water they might be innocuous, 

 but it is the border of mud left by the drying up of the 

 waters which appears to be the cause of malaria. The soil 

 of the beds of these jheels is a sticky, slimy mud, containing 

 a considerable amount of vegetable matter, and enriched 

 with the exuviae of numberless water-fowl. 



The drainage of jheels has been proposed as a general 

 measure, and in some instances has been carried out as a 

 method of getting rid of the unhealthiness they cause. In 

 Upper India, where it is said cultivation cannot be carried 

 out without irrigation, on account of the dryness of the soil 

 and climate, the soil and climate are to be made still more 

 dry by improved surface-drainage. To drain these jheels an 

 outlet must be made as deep as, or, where existing, must be 

 lowered to the level of the lowest part of their beds. 



The water coming into the jheel not being checked as before 

 by being spread over a large area, will not deposit the various 

 vegetable and mineral matters it contains in suspension, but 

 will carry them through the drainage outlet with the rush of 

 its stream ; the outlet will be eroded and enlarged by the rush 

 of water, which will further deepen the bed of the outlet, and 

 the rich mud of the bed of the jheel will be carried away, to 

 be deposited on the country lower down the stream, where on 

 exposure it will cause malaria and disease. Disease in the 

 neighbourhood of the jheel would temporarily be got rid of, 

 at the expense of increased disease to inhabitants of the 



