62 



CONDENSATION OF VAPOR AS INDUCED BY NUCLEI AND IONS. 



To reduce the other tables to the same standards (remembering that 

 n varies as m, while d and 5 are independent of it), is not necessary for 

 the present comparisons. In table 18, however, 10 w e = 2.i should be 

 replaced by io 6 w = 2 .3, where dp/p = o. 133. In table 19, dp/p = 0.273, 

 io 6 w = 4.i is to be replaced by io 6 7^ = 4.3. In all cases the initial 

 nucleations are thus increased. The new values for m are referred to 

 20 C. and the temperature coefficient is about 2 per cent per degree. 



35. Wilson's* data and conclusions. The following table (24) con- 

 tains Wilson's exhaustions (v t /v) at 18 to 19 C. and the correspond- 

 ing disk colors as I interpret them. It also contains the equivalent 

 relative drop of pressure dp/p used above. From these and the colors, 

 the diameters of fog particles (d} may be estimated, provided the series 

 in which these colors lie is known ; hence d. A ^ refers to the probable case 

 of the occurrence of the third and second series, d 2 1 to the very im- 

 probable case of the occurrence of the second and first series. Hence 

 if the values m be found for the corresponding temperature and ex- 

 pansions (dp/p) the nucleations n 3 2 and n 2 1 respectively follow. Wilson 

 gives but a single series between green coronas. There are two such 

 series and three definite green coronas producible, and I shall assume 

 that the very vivid upper one is meant. The first series is not pro- 

 ducible by any means known to me, except in the lower red coronas. 

 Hence I ignore n 2 1 and take 3 2 , in which case the data are distributed 

 similarly to my own, so far as the slope of the curves is concerned. 



TABLE 24. Estimation of the nucleation and size of nuclei corresponding to Wilson's 

 colors for wet dust -free air. Temp. 18 to 19 C. 



*Phil. Trans. Roy. Soc., vol. 189, p. 265, 1897. Cf. p. 285. 



