LVIII. T. W. SEAVER. 



there is no reason why they should not be used to pump 

 water from the rivers or from the sands and gravels of the 

 Tertiary drifts. To make their employment a success, 

 however, for irrigation purposes, it must be remembered 

 that their power increases as the cube of the wind velocity, 

 so that they should be strongly built and of large size. It 

 is also essential that they should pump the water into large 

 reservoirs, so that none of the power will be wasted, for it 

 is an axiom in windmill irrigation that the time to pump is 

 when the wind blows strongly. No expensive works are 

 required to transform at least small portions of our arid 

 plains into gardens, orchards, and meadow land, but only 

 an increase in the number of existing wells, and the employ- 

 ment of more powerful windmills. 



Hydraulic rams of a large size and modern make might 

 also be used with great advantage for raising water, and 

 they are the cheapest and simplest water lifters known. 

 With an average fall of only 8 feet, 3,500 gallons of water 

 can be raised 35 feet in 24 hours, so that with a battery of 

 say 10 such rams, at a total cost of say £100, an area of 

 30 acres could be irrigated. These rams have been con- 

 structed of great power, and are installed in the French 

 Department of Oorrege, working under a head of 20 feet, 

 raising 122 gallons per minute or 176,000 gallons per day to 

 a height of 81 feet. 



In this connection it may be of interest if I refer to a 

 very ingenious contrivance, which has been lately used at 

 Geneva for the purpose of increasing the available head of 

 water required for working turbines or rams. Two jets of 

 water are directed through the dam upon the surface of 

 the lower stream, tlieir action being to produce in it an 

 artificial depression in which the outlet pipes are placed. 

 Experiments have proved that by this means the head 

 could be increased by as much as 30°/°. 



