Appendix I, Determination of random coincidence in a fast-slow coincidence circuit; Appendix II, Multiple scattering during measurements of S-directional distribution from polarized nuclei, of S-y-circular polarization correlation, and of S-y-directional correlation.

The present paper is devoted to the determination of the heats of reaction of lanthanum ions with halogen ions within a broad concentration range of hydrogen halides. The enthalpies of the interaction of lanthanum perchlorate with perchloric and halogen acids increase with the increasing of acid molality from one to eight. The enthalpies of the interaction between lanthanum and halogen ions in water solutions are endothermic and decrease in the sequence; Cl > Br > J. The values support the fact of formation of lanthanum chloride complexes and point to the possibility of forming bromide complexes, but the question of the existence of iodide complexes of lanthanum in aqueous solutions is left open.