182 BARUS— METHOD OF STANDARDIZING [April 24, 



the influx of a high permanent positive voltage. Curiously enough 

 even when the lighting circuit is cut out, the effect remained with 

 undiminished intensity. It will appear elsewhere, that in the absence 

 of radium and of initial charge in the condenser, the equation 

 /q = CVo where Fo for any given ionization is a constant negative 

 quantity, applies very closely within the limits of measurable Vq 

 values. Hence in the presence of radium in the core of the cylin- 

 drical fog chamber and a positive charge, 



/o + 6oo7r/FA^^z'/(ln R,/R^) = QV. 

 Thus in this case 



NV = Kd{V—V,)/dt) —N'V' = K'd(—V'—V,)/dt, 



and for the same V^V, to a first approximation 



N-\-N' = d{K\n V + k' In V')y=v'/di, 



as before. If the equation for A^ is integrated and N/k^=^K, 

 since I^^CV^, V^ being intrinsically negative, 



F= e-^\ V - VJK) + VJK; V = e-^'\ V' + VJK') - VJK', 



where Vc and Vr' are the initial positive and negative potentials. 

 The constant Fo increases with the strength of the ionization but has 

 a fixed value for a given ionization. 



5. Data: High Ionization: Currents — The tables^ investigated 

 contain the mean potentials V, the positive and negative logarithmic 

 currents d{\og V)/dt (apart from the constant), the apparent 

 nucleation A'^ positive and A^' negative, computed from these data 

 and additional information as to conduction leakage and effect of 

 y rays. In most of the cases the corresponding logarithmic cur- 

 rents due to y rays outside the fog chamber was carefully measured 

 in the same units, by placing a short hard-rubber rod between the 

 end t of the aluminum tube, Fig. i, and the wire leading to the 

 electrometer. This cuts out the fog chamber but leaves the whole 

 remaining circuit undisturbed. Similarly the leak value of 

 d{\og V)/dt in the absence of radium and due to mere conduction 

 of moist parts is always quite negligible. Thus in the data in 



^ The tables will be removed for brevity, as Figs. 2-4 sufficiently repro- 

 duce the data. 



