Latent Heat and Surface Energy — Cohesion. 183 



would boil or explode into complete disintegration. Electronic 

 evaporation would begin much lower in the scale. 



I confess I had hoped that this ebullition temperature 

 would not have been so appallingly high, so that there 

 might have been a chance of reaching it, at least locally, in 

 the sun or some or! the stars. Nevertheless it is manifest 

 that at all really high temperatures the particles must be 

 immersed in plenty of synchronous as well as much other 

 radiation, and that accordingly copious emission could occur 

 at a much lower temperature. Applying a factor such as 

 26^ to the energy of emission, though without any real 

 justification, to represent the influence of the synchronized 

 radiation as a supplement to the irregular jostling, the above 

 estimate of temperature would come down. And it does not 

 seem unreasonable to surmise that if the sun's temperature 

 rose locally to something which we may suspect to be in the 

 neighbourhood of 7400° C, a violent eruption in its hydrogen 

 atmosphere, and a projection of electrons at 1/140 the 

 speed of light, might occur. Such projectiles would pass 

 the earth in about 18 hours. This however is a bye-issue 

 and not the essence of the paper. 



XIX. Latent Heat and Surface Energy — Cohesion. 

 To the Editors of the Philosophical Magazine. 

 Gentlemen, — 



ITH reference to Mr. D. L. Hammick's article (Phil. 

 Mag. ser. 6, vol. xxxix. No. 229, p. 32) in January 

 1920, I beg to call attention to "the fact that Bakker's 

 formula 



\ = a(i-i) 

 \«i t'a/ 



is in absolute contradiction to J. E. Mills's expression 



given in Young's ' Sioiehiometry ' (First Edition, 1908, 

 p. 153), with references to Jouru. Phys. Chem. vi. p. 209 

 (1902); viii. pp. 383 & 593 (1904) ; "ix. p. 402 (1905); 

 x. p. 1 (1906). 



On the basis of the latter result, Mills deduced that the 

 molecular attraction (between a pair of molecules") during 

 the transition from the liquid to the vapour states Eollows 

 the inverse square rule. The extensive field implied makes 

 this conclusion appear to me very improbable (although 

 Young refers to a corroboration by the late Lord Rayleigh), 



w 



