Electron spin relaxation times T1 and Tm of Tb3+ and Tm3+ in 1:1 water:ethanol and of Tb3+ doped (2%) in crystalline La2(oxalate)3 decahydrate were measured between about 4.2 and 10 K. Both cations are non-Kramers ions and have J = 6 ground states. Echo-detect... ...