Mr Glasson, Secondary Rontgen Rays from Metallic Salts. 441 



10 20 iO 40 SO 60 70 80 90 



Fig. 3. Screen (II) = Aluminium (pd = -017). 



10 20 30 40 SO 60 70' gO 90 



Fig. 4. Screen (II) = 5 Filter papers. 



20 30 10 50 60 70 SO 90 



Fig. 5. Screen (II) = Aluminium (pd- -008). 



