Heats of solution and viscosity B coefficients, for cyclic mono (quaternary ammonium) salts,(CH 3) 2 N (CH 2) n Br (n= 4–6) and cyclic bis (quaternary ammonium) salts,(Remark: Graphics omitted.)(n= 1–3) in water were measured, and the effect of structural changes in the solvent water upon the dissolution of both series of electrolytes is discussed.