254 BIEECT SOWING. 



sun, it would also retard radiation from the strips in the afternoon 

 and thus mitigate, if it did not altogether prevent, frost. 



Direction foe excessive insolation alcne. In the hot wea- 

 ther, when alone this danger exists, the sun rises for every place in 

 India more or less due east and sets more or less due west. Hence 

 in strips running east and west the seedlings would receive next to 

 no shelter from the vegetation standing on the adjoining uncultiva- 

 ted intervals, that is to say, would be practically exposed to the 

 -sun's rays during the whole time it remained above the horizon. 

 On the other hand, the young plants would receive most shelter, 

 if the direction of the strips were due north and south ; they would 

 then receive the sun's rays only from some hour before noon to the 

 same hour after it had passed its zenith, the length of time depend- 

 ing on the height and density of the vegetation referred to and on 

 the width of the strips. 



Direction for dangerous winds alone. It is obvious that 

 the strips should run as much as possible at right angles to the 

 direction of such winds. Saving local deflections due to the con- 

 figuration of the ground everywhere, and the sinuosities of the 

 coast line near the sea, the direction of violent winds in India is 

 either north-west or north-east or south-west. When not bring- 

 ing rain, the current that blows north-east also becomes a hot 

 wind at a certain distance from the coast. In the Himalayas the 

 dhadu or chilly wind that blows down from the snows, naturally 

 sweeps down the longer valleys, which of course all open out to the 

 south. The direction of the strips with reference to dangerous 

 winds is thus a very variable one, depending on the posiyon of the 

 place with respect to the sea and to the configuration of the land 

 in the neighbourhood. 



Direction for erosion alone. If the soil on decidedly in- 

 clined ground is loosened in any direction but that following 

 horizontal contours, rain or snow water, rushing downwards, would 

 scour and wash away the loosened soil in the strips, together with 

 the seeds or young plants that the latter may contain, and thus 

 also endanger the stability of the slopes. 



Direction generally considered. In ahgning strips on slopes, 

 all other considerations must yield to the essential one of preserv- 

 ing not only the sowings but the ground itself, and there is thus 

 no alternative but to follow horizontal contours. Otherwise the 

 direction would be as follows : — 



a. if protection has to be secured against frost and excessive 



