Note Footnote b: — APPENDIX H.

Explaining why the volume flowing from a well does not depend upon the diameter of the "static" pressure of the water, Mr. Henderson says that the flow depends principally upon the relative altitudes of the outcrops of the water-bearing beds, and of the mouth of the bore or well, and upon the character and texture of the porous beds from which the well derives its supply. The static pressure is ascertained by stopping the flow by artificial means, when the pressure generally rises, sometimes quickly, at other times slowly, until it reaches a maximum. But when the well is again opened it will be found that the static pressure has been more or less reduced by friction. This reduced pressure is called the "hydraulic." The hydraulic pressure can never exceed the static pressure; nor can the volume of water flowing from an artesian well be ascertained by its pressure, or the height to which the water may rise over the top of the casing, any more than the pressure can be ascertained by knowing its volume.b