IHC) GXATS Oli MOSQUITOES — CHAPTER VIII 



cause water-logging, while the freedom of the supply, and 

 especially its independence of the individual efforts of the 

 user, leads to carelessness in its use, and hence to leakages 

 and puddles ; but it must be distinctly understood that, for 

 all crops except rice, the puddles are the result of the abuse 

 and not of the use of irrigation, and that the reason why 

 these puddles are sufficiently permanent to be harmful is 

 that the water is not absorbed on account of the saturation 

 of the soil with canal water, nearly three-quarters of which, 

 as will be seen, represents waste of some sort. In record- 

 ing my beliefs as to the harmlessness of domestic irrigation, 

 it must be understood that I refer only to field irrigation. 

 Gardening as carried on in the parts of India with which I 

 am familiar is conducted in a way that makes each garden 

 a paradise for Mosquitoes. 



In considering the influence of canals in favouring the 

 production of puddles, and therefore of malaria, it must be 

 remembered that but a comparatively small proportion of 

 the water entering the canal at its head works ever reaches 

 the fields. In a departmental note "On the Irrigating Duty 

 of Bari Doab Canal," Mr. B. G. Kennedy, of the Indian 

 Public Works Department, states that out of every 100 

 cubic feet of water entering the canal during the winter 

 months of 1881-82, twenty were lost in the canal proper, six 

 in the larger distributories, twenty-one in water-courses, 

 twenty-five by waste in various ways, so that only twenty- 

 eight was left to do all the useful work of irrigation. That 

 is to say, that considering the canal as a machine, its 

 efficiency was but 28 per cent. 



Now in this canal alone, wdiich is by no means the largest 

 of our Indian irrigation works, the average flow of water 

 is over thirteen millions of gallons per minute, and this 

 enormous amount of w^ater is distributed, in work and 

 waste, over 1,200 square miles, or, in other words, is 

 equivalent to a rainfall of about 40 inches per annum. But 

 this gives no adequate idea of what may be the local effects 

 of the system. In the case of the canal in question, for 

 example, the distribution of the water is very different at 

 different seasons of the year. 



