A Mossbauer spectrometer which uses optical interferometry in the Doppler drive, and the mechanical design for the electromechanical drive described in last years report are presented. A description of chemical shift of iron compounds is given. The use of a correction factor for certain source detector geometries are described for Mossbauer spectroscopy. A new source of Sn(119m) in palladium which produces a very narrow line width is also described. For the first time a trace element has been certified in a Standard Reference Material with the assistance of the activation analysis technique. Flux measurements for the NRL reactor are given. A number of special analyses for various NBS projects by activation analysis are described (e.g. argon in silicon, chlorine in polystyrene, hafnium in zirconium). A beta-gamma sum coincidence gamma ray spectrometer is described. A constant potential electrochemical method of analysis using radioisotopic tracers is presented which has potential high sensitivity. A method of using radioisotopic tracers in heterogeneous equilibrium between an aqueous medium of cobalt to be analyzed and manganese dioxide impregnated filter paper is described. Some results on the precision of the substoichiometric radioisotope dilution analysis of silver and iron are presented.