C. Barus — Ionization of Water Nuclei. 



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Art. IX. — The Ionization of Water Nuclei ; by C. Barus. 



1. Introdtictory. — In my report to the Smithsonian Institu- 

 tion (August, 1902) and elsewhere,* I pointed out the desira- 

 bility of further investigations on the Lenardf effect. While 

 my work in this direction was in progress, a paper due to J. J. 

 Thomson appeared, covering similar ground. Nevertheless I 

 shall venture to publish the following results since the subject 

 is looked at from a somewhat different point of view, obtained 



1 * 1 



r »* 







M 



\ 



m 



(bcurth, 



Figure 1. Apparatus for comparing nucleation and ionization ; A, coro- 

 nal chamber ; R, exhaustion reservoir ; M, Mariotte flask ; C, tubular con- 

 denser ; P (to be inserted in the conveyance tube, e) phosphorus ionizer ; 

 G, G[, vacuum gauges ; F, cotton filter ; B, storage battery terminals. Tubes 

 p to suction pump ; a, to atmosphere; c, e', for exhaustion ; e, for convey- 

 ing the nuclei into the condenser ; d, for filtration ; h, from the hydrant. 

 Extremely fine jets of water shoot out from the needle pricked lead pipe, j. 

 Supports g, g are metallic ; i, i, insulating. 



from coronal and other measurements. My chief purpose, 

 however, is to find whether as a result of Thomson's^ remark- 

 able discovery of radio-activity associated with water nuclei, 

 the theory given in my u Experiments with Ionized Air"§ is 

 to be abandoned. The experiments of this paper show, I 

 think, that this is not necessary. They contain, it seems to 

 me, an interesting confirmation of the views stated in the third 



* Science, xvi, p. 633, 1902. 



fLenard, Wied. Ann., xlvi, p. 584, 1892. 



% J. J. Thomson : Experiments with Induced-radio-activity of Air, and on 

 the Electrical Conduction Produced in Gases When they Pass through 

 Water; Phil. Mag. (6), iv, p. 352, Sept., 1902. 



§ Smithsonian Contributions, No. 1309, 1901. 



A.M. Jour. Sci.— Fourth Series, Vol. XY, No. 86.— February, 1903. 

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