OBSERVATIONS ON IRRIGATION WORKS IN INDIA. 157 



as it did contain was carried on to the fields, where it was 

 useful as a fertihzing agent. The chief part in this reform, 

 which saved much expense in dredging, was taken bv a 

 gentleman whom I see present this evening. AVeeds were 

 another of our difficulties. The moment the water was clear 

 and the supply low, so that its velocity in the canal was small, 

 they commenced to spring up, and I can, having seen this 

 example, well understand how weeds have actually blocked and 

 in fact extirpated rivers in Central Asia and Eg^^pt. The 

 pecuKarity of the weeds, at least those with which I am 

 personally acquainted, is that so far as screw steamers are 

 concerned they only materially impede the progress of the boat 

 when it is travelling with the current. I remember on one 

 occasion taking a distinguished party some 50 miles, in a small 

 steamer up a canal ; the journey was performed with no trouble, 

 and indeed we had not much difficulty during the tirst 40 miles 

 of the journey back, but it took us quite four hours to do the last 

 10 miles, and as I was in charge of the canal I was not a little 

 mortified. I mention the circumstance as a good example of 

 learning by experience. The weeds I may say have been much 

 diminished by the measures taken to prevent silt deposit and 

 what is perhaps of nearly equal importance, paddle r.teamers 

 are now used. Weeds have very little effect on the progress 

 of paddle steamers, and after such a lesson I took all pos- 

 sible precautions for the future. The canals with which I 

 liave been personally connected, have locks, and are used for 

 navigation as well as for irrigation. There is considerable 

 doubt as to whether this is a wise arrangement, as with a 

 navigation canal it is desirable to keep the velocity of the 

 current as low as possible, whilst in respect to canals, for 

 irrigation only, a high velocity is desirable, so that the canal 

 may not be larger than is necessary, and, further, the higher 

 the velocitv the more silt the water will carrv on to the 

 fields. 



The main canals leading off from the rivers having been 

 constructed, branch canals taking off from them are excavated, 

 and other channels, known as distributaries, are again dug 

 leading off from the branch canals, until the water is delivered 

 well into every village, which may be taken as an area of say 

 2,000 to 3,000 acres. From these distributaries channels are 

 led into the fields ; these minor channels have usually been 

 made by the villagers, but the tendency is now for water to be 

 led to each holding by channels made when the distributaries 

 are constructed. Here I may perhaps mention that upwards 



