154 
FLORIDA STATE GEOLOGICAL SURVEY. 
need not interfere in this case as long as the measurements are 
taken vertically. 
“The method for determining the discharge of horizontal 
pipes requires a little more care. First, measure the diameter of 
the pipe as before, then the vertical distance from the middle of 
the opening of the pipe, or some convenient point corresponding 
to it on the side of the pipe, vertically downward six inches —a to 
Fig. 5. —Illustrating method of measuring the flow of an artesian well 
from horizontal and vertical pipes. After Todd. 
b, then from this point strictly horizontally to the center of the 
stream— b to e. With these data, the flow in gallons per minute 
may be obtained from the table. It will be readily seen that a 
slight error may make much difference in the discharge. Care 
must be taken to measure horizontally and also to the middle of 
the stream. 
“Because of this difficulty, it is desirable to check the first 
determination by a second. For this purpose, columns are given 
in the tables for corresponding measurements twelve inches below 
the center of the pipe. Of course, the discharge from the. same 
pipe must be the same in measurements of the same stream. In 
this case, the occurrence of wind, blowing either with or against 
