gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1968.036.284.16 Short Communications Dielectric Properties of Hydroxyapatites—A Reply Cockbain A. G. Smith G. V. The Plessey Co. Ltd. Allen Clark Research Centre, Caswell, Towcester, Northants. 12 1968 36 284 1171 1171 Copyright © 1968, The Mineralogical Society 1968