l6 A CONTINUOUS RECORD OF ATMOSPHERIC NUCLEATION. 



original ions are associated with the nuclei by which the dense fogs and coronal 

 sequences are produced, even at the outset. It was with a view to possibly 

 restoring some of this lost ionization that the great variety of experiments 

 detailed in the chapter were undertaken; but not a trace of restoration was 

 observable in any case. 



Moreover, the whole of the original ionization vanishes symmetrically, for 

 the nuclei as a whole are neutral throughout. At least with so insignificant a 

 residue of the original ionization, the decision as to whether more positive or 

 more negative ions have vanished is a delicate one and of trifling interest in 

 this connection. For the phenomena are now all of the order of the leakage of 

 the electrometer and appurtenances. If when loo ionized nuclei of the phos- 

 phorus emanation are suddenly introduced into an atmosphere saturated with 

 water vapor, the ionization of 96 has vanished without a record, while the re- 

 maining 4 are in equal number positive and negative, it is unlikely that negative 

 ions can have greater affinity for water vapor or be more remarkable in their 

 efficiency as condensation nuclei than positive ions. 



Finally, it does not appear that the ionization lost so soon after the removal 

 of the emanation from the phosphorus surface can ever be restored, notwith- 

 standing the fact that in the condensation chamber nuclei may be made to 

 pass from the fog particle to the nuclear stage of size and density an indefinite 

 number of times. Hence it follows that it is the ante-nuclear stage by which 

 the ionization is introduced. 



In one respect the experiments with phosphorus are unsatisfactory: it 

 takes some time before the condensation chamber can be adjusted for condensa- 

 tion on the phosphonis nucleus as it is necessary to introduce the nucleation 

 from without. Placed within the chamber over water, phosphonis emits a 

 dense filament of smoke, and is relatively inefficient. With water nuclei there 

 is no such difficulty; for here the nuclei are most efficiently produced in the 

 condensation chamber itself, while the ionization may be studied without loss 

 of time. The results are given in the succeeding chapter. 



As a whole, the experiments agree well with the original hypothesis, that 

 nuclei and ions are distinct entities; that the former constitute the residual 

 product left after the corj^tiscles representing the ionization have been expelled. 

 Radio-activity in case of the relatively gentle breakdown of molecular structure 

 here in question can hardly be anticipated. If a nt:cleus, like that of phos- 

 phorus, for instance, shows a tendency to grow continuously, until it finally 

 appears as part of a visible smoke, there may be continuous ejection of electrons. 

 In such a case electric conduction through the gas freighted ^vith these nuclei 

 wotdd follow Ohm's law, as is actually the case for phosphorus. 



