| The theoretical basis of this method of measuring the phase constant and index of absorption of short waves in liquids was deduced by hr. Gordon Williams of King's College, London. The apparatus he designed and made has been modified, but the theoretical basis is unchanged. A series of results has been obtained to test the degree of agreement between theory and practice. The method has been critically compared with other methods of measuring the propagation constants of liquids at similar frequencies. The theory applies to both transmission lines and wave-guides. A transmission line was used because, if a series of measurements is made, using a range of wave-lengths, the cut-off wave-length might be reached with a wave-guide, and the guide itself would cause attenuation to occur, whereas the range of wave-lengths at which free propagation can occur is much larger for transmission lines. |
