SUBMERSION OF VINEYARDS. 



199 



The rouet seems to give better yield for a difference of 

 level under 16 feet, but it cannot be shifted about like the 

 centrifugal pump, and cannot be used in certain properties 

 where the blocks of vines are far apart. Norias and chain 

 pumps have also been used, but they do not give such good 

 results as the above machines. 



These various elevating machines are generally worked by 

 steam, this being the cheapest and the handiest means of 

 working. The cost of the operation varies between 24s. and 



Fig. 170. Gwyne's Centrifugal Pump. 



32s. per acre when the water has not to be raised over 16 

 feet. This should be the maximum limit in practice. The 

 machinery is sometimes established in a fixed position (Fig. 

 172) on the highest point of the vineyard to allow the water 

 to run all over the surface through small channels made for 

 the purpose. In other cases the machinery is portable and 

 may be shifted from one block to another (Figs. 170 and 173). 

 The system of fixed machinery should be preferred whenever 

 possible ; it is cheaper, works better, and lasts longer. It 

 also saves time and enables the water to be distributed more 

 regularly over the whole vineyard. 



