120 C. Barus — Ionization of Water Nuclei. 



water vapor. An initial excess of positive or negative ions 

 means a corresponding excess in the small electrical residuum. 

 Regarding Wilson's famous experiment, I have already 

 expressed my belief that it is the unavoidable synthesis in a 

 region of intense ionization that furnishes the nucleus, and 

 that such synthesis must be different on the acid and alkaline 

 side of a battery.* The same explanation would apply to 

 nuclei obtained from any kind of radiation. 



17. Induced-radio-activity. — In none of the experiments 

 was observable radio-activity imparted to the core of. the 

 condenser. The insulation determined before and after the 

 passage of the nucleated medium showed greater leakage in 

 the first than in the second instance, whether the charge was 

 positive or negative. This corresponds to the usual electric 

 absorption of insulators. If radio-activity had been present, 

 the latter insulation should have been worse than the earlier, 

 instead of the reverse case, invariably observed. 



True the potentials did not exceed 100 volts and in J. J. 

 Thomson's experiments a Wimshurst machine was needed to 

 bring out the radio-active effect. But if within the limits of the 

 above experiments no such effect was demonstrable, I do not 

 see that one is at once at liberty to assume it ; for it is quite 

 possible that the enormous potentials of the electric machine 

 introduce conditions which have no bearing on the work of 

 the above pages. One may imagine, for instance, that a 

 compound of metal and water nuclei may be stable in presence 

 of a strong negative field, bufc unstable in the absence of the 

 field, just as I suppose that a compound of oxygen and phos- 

 phorus is stable in presence of excess of phosphorus (close to 

 the surface of the phosphorus) but unstable in excess of air 

 (away from the phosphorus), and that the dissociation is 

 accompanied by ionization. To this extent I have ventured 

 on an independent explanation of the phenomena detailed, in 

 keeping with my earlier work. 



18. Conclusion. — A few general remarks may be added. 

 Referred to a cubic kilometer the charges of the above nuclei 

 would aggregate to about 200 coulombs, with an excess of 

 negative charge as stated. If this region were spherical, with 

 a superficial capacity, and if the charge of a given sign were 

 transferred to the surface, its potential would be, in the 

 average case, of the order of a thousand million volts. Finally 

 the mobility of the nuclei is of the order of about eight- 

 tenths of a mile in the unit electrostatic field, and the mere 

 attrition of water by water is sufficient to generate them. 



Brown University, Providence, E. I. 



* Science, xvi, p. 633, 1902. 



