132 CONDENSATION OF VAPOR AS INDUCED BY NUCLEI AND IONS. 



for K r and K, and these_are taken from section 79, where b = K = io* 

 and c = K" = o.o356, fairly reproducing the data obtained with ions in the 

 fog chamber. 



Naturally it is hazardous to accept the constants for ionized air and 

 apply them to the case for phosphorus emanations. Hence the order 

 of values of n in table 54 is surprisingly good. For similar values of n 

 are obtained with the fog chamber where the initial nucleation has been 

 found by the totally different method of successive exhaustions. 



There is an observable increase of n with the volume of nuclei-bearing 

 air (V liters per minute) passing through the tube in a given time. But 

 this is not unreasonable, because when the velocity of the current is 

 greater, fresher phosphorus emanation reaches the mouth of the absorp- 

 tion tube. Moreover, since the criterion of an efflux of fixed total nuclea- 

 tion (nV) per minute is the color of the field of the steam tube, a better 

 general agreement must not be anticipated. Finally, the activity of 

 phosphorus in producing ionized emanations varies with temperature 

 and V is very difficult to obtain closer than y o = o.5 to 0.8. The 

 constants b and c are thus provisional values. 



The high results for brown rubber are clearly due to low values of 

 V found in the experiment. Thus if V = o.8 had been taken instead 

 of V = o.6 the following values would have resulted: 



III [ ^~ I- 3 I- ? 2-2 2 '^ 3' 3 4' 2 liters per minute. 

 \ io 8 = 2.0 2.4 3.6 4.0 6.0 8.8 



v f V= 1.5 1.9 2.3 2.8 3.1 2.5 liters per minute. 

 \io e = 4.0 4.0 4.0 5.2 5.2 6.4 



These are much nearer the other values, showing that the great diffi- 

 culty of finding V , the influx in the absence of an absorption tube, 

 is the outstanding discrepancy which is principally responsible for the 

 fluctuation of data. There seems to be no effect due to either diameter 

 of tube or substance of walls. 



In Series I and II, a few of the tube-lengths are computed for a mean 

 constant n = 3, 600,000. The agreement is admissible in case of series I 

 but not in series II, since a tube-length of 10 cm. makes an appreciable 

 difference in V. 



In the above equations, since nV = n V , it is therefore possible to 

 pass at once to the nucleations by writing C = n V , or 



Krnx/2.$6C _ l^o 



It is therefore well worth while to try the experiment with dust-free 

 air ionized by radium or the X-rays, in which case the complications met 

 with in case of phosphorus nuclei will be avoided. The steam tube, 

 which is ordinarily fed with atmospheric air, may, however, have to be 

 modified. 



