286 



I >r. (r. Johnston i > Stont-y. 

 Table V. Saturation -Pressures of Steam. 



Kegnault were calculated. Taken in conjunction with the differential 

 throttling experiments, and with the direct measurement of the specific 

 heat by the electrical method, this is very strong evidence that 

 Regnault's formula for the total heat is incorrect, and that the values 

 of the total heat and latent heat given in Table III, and supported by 

 the experiments of Griffiths and Joly, should be accepted in its place. 



"Note on Inquiries as to the Escape of Gases from Atmospheres." 

 By G. JOHNSTOXE STOXEV, M.A., Hon. D.Sc., F.R.S. Received 

 and Head June 21, 1900. 



We have now three investigations which profess to supply informa- 

 tion about the escape of gases from atmospheres. Two of them, those 

 of Messrs. Cook and Bryan, reason forward by the help of the kinetic 

 theory of gas from the supposed causes ; the third, which is that pre- 

 ferred by the present writer, reasons backward by the help of the same 

 theory from the observed effects. 



Mr. Cook's investigation, which will be found in the ' Astrophysical 

 Journal ' for January, 1 900, seeks to compute the proportion of mole- 

 cules which can attain the speed requisite for escape by means of the 

 formula which Maxwell published in 1860, assigning the proportion of 



