MEASUREMENT of the primary porosity of massive limestone gives little indication of the rate of underground movement, which takes place largely along joints and bedding planes. There is also the possibility that these zones of water movement can exist as discrete systems and not in a uniformly permeable interconnected lattice1. Consequently, the permeability of a stratum of any fractured rock is difficult to estimate. The purpose of this communication is to report a finding which reinforces the hypothesis that the flow-through time of water in massive limestones might be inferred from seasonal changes in the solute concentration of the water2
