CALORIMETRIC DETERMINATION OF HALF LIFE OF Ra$sup 22$$sup 6$

Calorimetric measurements were made af three equilibrium radium preparations (Ra I, Ra II, and Ra III) with total alpha impurities not exceeding 0.2 wt.%. Based on the data for the alpha and BETA spectra of the radium series, the value epsilon was equal to 25.335 Mev ( plus or minus 0.3%). Using the above value the calculations of the Ra/sup 226/ half life showed T = 1577 plus or minus 9 years. Consequentiy, the specific activity, connected to T by a simple relation Z = 1.847 x 10/sup 21/T, is Z = 3.71 plus or minus 0.02 x 10/sup 10/ fission/sec g. (R.V.J.)