THE 



SCIENTIFIC PROCEEDINGS 



OF 



THE KOYAL DUBLIN SOCIETY. 



No. 1. 



EXPEETMENTS ON THE ELECTRIFICATIOISr PEODUCED BY BEEAKING 

 UP WATEE, WITH SPECIAL APPLICATION TO SIMPSON'S THEOEY 

 OF THE ELECTEICITY OF THUNDERSTOEMS. 



By PEOFESSOE J. J. NOLAN, M.A., D.Sc, and J. ENRIGHT, B.A., M.Sc, 



University College, Dublin. 



[Read Mauch 2S. Printed Jl'ne 1, 1922.] 



Introduction. 



The work described in the present paper is an extension of certain experiments 

 carried out by one of us on the electrical charges produced by breaking up water. 

 In the previous work^ water was broken up in two ways, (1) by allowing water- 

 drops to fall into a strong horizontal air-blast, and (2) by means of a sprayer. The 

 water, as is well known, takes up a positive charge. This charge was measured, 

 and it was found that the magnitude of the charge per c.c. depended on the size 

 of the drops into which the water was broken, increasing as the size of the drops 

 decreased. The result of a considerable number of observations tended to show 

 that the charge per c.c. on the water was proportional to Ijr, where r is the radius 

 of the drops. It was pointed out that this could be interpreted by saying that 

 the total charge given to the water was proportional to the area of new water- 

 surface created. The charge per square cm. of new surface was calculated, and had 

 a value of about 2 to 3 x 10"^ electrostatic units, both methods of breaking up the 

 water giving the same result. The smallest drops tested were of radius 5'9 x 10^^ cm., 

 and the corresponding charge (ihe highest found) was 1'36 e.s. units per c.c. The 

 water used was the ordinary distilled water of the laboratory ; no attempt was 

 made to reach any higher standard of purity. 



Apart from the theoretical interest in the investigation of this phenomenon, it 

 has an important connexion with the theory of thunderstorms put forward by 

 G. C. Simpson. = As is well known, this theory traces the electric sepai-ation which 

 gives rise to the lightning discharge to the breaking up of rain-drops in the strong 



1 .J. J. Nolan, Proc. Roy. Soc, A, vol. 90, 1914. 



2 (J. c. Simpson, Phil. Trans. Roy. Soc, A, 209, 1909, and Phil. Mag., 30, 1915. 



SCIENT. PEOO. R.D.S,, VOL. XVII, NO. I. 



