THE I R RIG A TION AGE. 119 



suited in failure, yet, sand points, large enough in diameter to equal 

 one-half the diameter of cylinder used, have nearly always when driv- 

 en down deep enough into the sand furnished abundance of water to 

 supply the largest pumps when working at 25 to 35 strokes per minute. 

 If an open well is to be made, a substantial curbing must be used and 

 the well made large and deep,- that the pressure will cause the water 

 to flow in rapidly, and the large area give sufficient surface to supply 

 enough water. The lower sections of curbing should be filled with 

 small holes very small to admit the water. 



Where sand (drive well) points are u^ed, an open well properly 

 cnrbed should be made deep enough to reach down to water bearing 

 sand, (in all sections where an abundant supply of water is found in 

 strata of sand) and then the point or points should be pushed down 

 until there is every reason to expect that the supply of water will feed 

 the pump without exhausting the water from over the sand point 

 for should the water be exhausted from over the sand point then 

 the pump would be denied a full supply, for the same reason the point 

 should be lodged in such water bearing sand or else the pumps will 

 not be supplied, and injury may be done to the pumps, and the mill 

 also may suffer injury, through the force necessary to create vacuum. 

 Where several points are used to supply one cylinder, these are usu- 

 ally small enough in diameter that they may be driven, and even 

 where one point is to supply the cylinder of small diameter, it may be 

 driven, but large points should be put down, by first boring or drill- 

 ing down into the sand, and casing to prevent the sand from caving 

 in, then after the point is let down to proper depth and lodged in rich 

 water bearing coarse sand, the casing should be removed by puddling 

 it up and the sand permitted to fall in against the sand point. Enough 

 suction pipe should be added to the sand point to bring the pipe up to 

 top of water-bearing sand where the cylinder is to be located. 



In all sections where the strata of water bearing sand is thin or 

 too poorly supplied with water to afford a supply to the pump, a well 

 should be made and properly curbed down to the bottom of the sand 

 strata, and a hole bored or drilled down to second water, which usu- 

 ally supplies a sufficient quantity of water and which often rises up to 

 the level of first water and sometimes even above it. 



