DAM-MAKING. 225 



tube 16 ft. high the pressure on any given square inch 

 will only be 7 J lbs. 



The most convenient way of paying for dam work 

 is by the cubic yard, the general price being from Is. to 

 2s. a yard, the farmer finding carts, oxen, and drivers ; 

 but, of course, much depends on the nature of the soil. 

 The farmer should be careful not to make the mistake of 

 measuring the embankment instead of the excavation, 

 or he will pay dearly. Many farmers are deterred 

 from adopting payments by this plan, thiid^ing from 

 the shape of the ground that it would be difficult to 

 measure, but when tried it is very simple. 



Yery much more might be done than is done by 

 lookinof for water under the surface. We have one 

 farm that was badly watered, but by simply noticing 

 five different places where some few rushes grew, and 

 sinking only four feet, we came on perennial springs in 

 every case, which all rose to the level of the ground, and 

 in some cases ran down the kloofs. Our experience 

 would teach us that wherever rushes grow in Karoo 

 country, there is a spring not far down, and that from 

 the appearance of the rush a very fair idea can be 

 formed of the depth it is down. 



On three other spots where a hard round rush was 

 growing, we sank wells and got water in all at fourteen 

 feet, eighteen feet, and twenty-one feet respectively ; and 

 p 



