Thermal conductivities have been measured with longitudinal heat flow methods where the experimental arrangement is so designed to accommodate heat flow in only the axial direction, temperatures are constant, and radial heat loss is prevented or minimized. For the sake of simplicity the conductivities that are found by that method in all of its variations are noted as L conductivities, those that are found by radial measurements of the sort are noted as R conductivities, and those that are found from periodic or transient heat flow are distinguished as P conductivities. Numerous variations of all of the above and various other methods have been discussed by some G. K. White, M. J. Laubits, D. R. Flynn, B. O. Peirce and R. W. Wilson and various other theorists who are noted in an international Data Series from Purdue University, Volume I pages 14a–38a.