Miscellaneous. 274 [Sept. lUOG 



Prom the field laterals there diverges a system of parallel furrows on the 

 areas between which crops are grown. These furrows are generally from G to 9 

 nches in depth, while the distance between them varies from twenty-four inches 

 to as many feet according to the crops to be watered. The length and gradient 

 of the furrow varies with the distance apart of the field laterals, and to some extent 

 with the soil, the object being to cause all the water in the furrow to sink into the 

 soil and to allow none to escape. If the furrow is too short and too steep water 

 will flow away and be lost; if on the other hand it is too long and fiat it will be 

 absorbed before the end is reached and part of the land will remain unwatered. 

 The best length and gradient is found by experiment, and where the actual fall on 

 the land is excessive, the furrows run at an angle to the greatest slope so as to 

 reduce the gradient on them. 



The depth of the furrow is also a matter of experiment, but the tendency 

 during recent years has been to increase the depth, as by so doing the area through 

 which soakage into the ground takes place is increased and the risk of flooding the 

 land between the furrows is diminished. 



The water is diverted from the field lateral to the furrows by damming the 

 former with earth below the mouth of the furrow, but more recently the plan 

 has been adopted of inserting small pipes varying from f" diameter to about 

 2" diameter through the side of the field lateral into the furrow, as by so doing 

 a more regular distribution of water is obtained. 



Flow from the lateral to the furrow is permitted for a period of time 

 varying with the crops to be watered and the supply available, but in all 

 cases after the flow has ceased and after the water has sunk into the ground ; but 

 before the surface has become entirely dry, the surface soil in the furrow is culti- 

 vated, that is the top to a depth of two or three inches is turned over. By this 

 means the capillary tubes by which the water passed into the soil are broken up 

 and the re-evaporation of water through them is prevented. 



(To be continued.) 



Mosquitoes and Anti-Malaria Campaigns. 



The following letter from the "London Times " is worthy of attention in 

 Ceylon, as showing the results of conscientious work directed against the propa- 

 gation of Malaria by mosquitoes. Nothing of the kind has so far been attempted 

 in the Island, chiefly owing to a feeling of helplessness in a country where 

 the possible breeding places of the Anopheline mosquitoes are so multifarious. 

 But with the example of work successfully accomplished at Klang and Port 

 Swettenham, under circumstances comparable with those prevailing in Ceylon, 

 we have— as pointed out by Dr. Ronald Ross— no excuse for neglecting similar 

 measures here. At any rate, until the attempt has been made and failed we have 

 no right to complain of the mortality and widespread sickness credited to this 

 disease (malarial fever). Even should these measures fail in some of the wetter 

 districts, the couutry along the Northern line — notorious for the prevalence of 

 malaria— would lend itself more hopefully to successful treatment. 



It must be remembered that infection is principally carried by mosquitoes 

 bred in the immediate vicinity of any settlement, so that, to greatly reduce the 

 danger of infection, it is not essential to operate upon a large tract of country. 

 Each breeding place that is suppressed or rendered harmless will have an 

 appreciable effect in the reduction of the disease. 



E. ERNEST GREEN. 



