Moisture Dciwsitcd from the SoutJi-East Clouds. 407 



practically a,ll that water is absorbed by the soil and the vegetation. 

 The roots and underground stems of the plants penetrate the earth 

 in all directions, and form a spongy, matted mass, varying in thick- 

 ness from a few inches to several feet. This sponge absorbs a large 

 amount of moisture, and only when it is fully saturated will it allow 

 any excess to drain away into the jfissures of the rocks below. 

 Simultaneously the plants refill their tissues every time the roots 

 become moist, hence it is obvious that a large quantity of the mois- 

 ture thus condensed is retained by the plants and the soil. There 

 may be an inch of condensation or more and yet nothing might be 

 able to flow away, for where the condensation is at its highest the 

 vegetation will be the thickest and tallest. As soon as the conden- 

 sation ceases evaporation begins. It is well known that even the 

 south-east wind blows sometimes without forming a cloud on the 

 mountain. During clear weather the store of water in the huge 

 sponge on the mountain becomes rapidly exhausted until another 

 good south-easter comes to fill it again. When, however, the south- 

 east clouds cover the mountain for several days in succession, a 

 considerable quantity of water must find its way into the rocks, and 

 hnally into the springs, hence I am of the opinion that the varying 

 yield of the springs in summer, especially during the latter part of 

 it, is largely influenced by the longer or shorter duration and the 

 frequency or rarity of the south-east clouds, , 



It was interesting to me to find the other day that a similar effect 

 had been surmised by others. In Dr. Brown's book on the " Water 

 Supply of South Africa " occurs the following passage : " These 

 springs (springs above Cape Town) were produced, in all probability, 

 in a great measure by the percolation through the masses of Table 

 Mountain of moisture deposited on the summit by the cloud pro- 

 duced on the mountain by the south-easters in the summer season," 

 and a few pages further on the author quotes a statement by Mr. P. 

 Fletcher : " I believe, from what I have observed, that there is much 

 more moisture deposited in the mountain in summer than is generally 

 supposed." 



In support of this view I may also mention the experience of Mr. 

 William Hunt at Stellenbosch, who, as the owner of the mills, has a 

 permanent right to a certain share of the stream coming from the 

 Jonkershoek valley. Naturally he has watched the quantity of 

 water in the stream, especially during the dry season, and he states 

 it as his experience that invariably after a severe south-easter the 

 quantity of water in the stream increases considerably. 



This side of the question, however — that means to say, the 

 influence which the south-east clouds have on the yield of springs 



27 



