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Fig. 1. Apparatus used to test the flow system (includes measuring system, water supply system, and water delivery system but excludes core) for repeatability. Inclusion of core allows the apparatus to be used for falling head measurements. The measuring system is limited to the pressure transducers and the cylinder to which they are attached. Pressure transducers P1 and P2, mounted on cylinder a distance Hp apart, are used to measure water head in the cylinder. Maximum cylinder fill height was regulated by Mariotte device at H1. Minimum cylinder fill was regulated to H3. Manual valve V2 and automatic valve V1 regulated water flow. Switch SW energizes control relay R. SW simultaneously opens valve V1 and sends a signal to the data logger. 
H is related to total water flow from cylinder.
