304 Royal Society : — Mr. G. J. Stoney on the Physical 



The appearance and disappearance of the lines is in close con- 

 nexion with the periods of the " charge : " the commencement 

 of the combustion-period, in which the decarbonization of the 

 iron begins, as well as the end of the decarbonization, can be ac- 

 curately determined by means of the spectral apparatus. But 

 the occurrence of a group of lines and of an isolated line in the 

 blue-violet part of the spectrum during the cooling-period, by 

 which a particular state of this is indicated, must especially be 

 noticed ; and as these lines also again disappear before the others, 

 their appearance and their disappearance, which invariably take 

 place in the last five minutes of the charge, must acquire signifi- 

 cance as an indication of its termination. 



XL. Proceedings of Learned Societies, 



ROYAL SOCIETY. 

 [Continued from p. 241.] 

 June 20, 1867. — Lieut. -General Sabine, President, in the Chair. 

 HPHE following communications were read : — 



-*- " On the Physical Constitution of the Sun and Stars." By 

 G. Johnstone Stoney, M.A., F.R.S., F.R.A.S. 



An attempt is made in the memoir of which this is an abstract to 

 take advantage of the insight we have gained within the last few years 

 into the molecular constitution of gases, and the laws which regulate 

 the exchanges of heat that take place between bodies placed in pre- 

 sence of one another, and to apply these new materials to the inter- 

 pretation of the phenomena of the photosphere of the sun, the appear- 

 ances presented during total eclipses, and the information about both 

 sun and stars given by the spectroscope. 



. In an inquiry like this, where we are obliged to put up with such 

 proofs as the materials at our disposal can supply, we must be content 

 to accept results of every variety of probability, from that degree, 

 bordering upon certainty, which commands an unhesitating assent, 

 to that of which the chief scientific value is that it prompts to further 

 investigation and points out a path. Those who read the memoir 

 itself will best judge of the probability of each conclusion from the 

 proofs laid before them ; but in this sketch of its contents it may not 

 be useless to indicate what is the value put upon each result by the 

 author, since the proofs must in many cases be entirely omitted. It 

 will be convenient to do this by numbers. 



The probability 4, then, is to be understood to imply that the 

 matter in hand appears to the author to be fully made out. He would, 

 for example, assign this probability to the wave-theory of light, and 

 to the main features of the theory of the molecular constitution of 

 gases which have been worked out by Clausius and others within the 

 last twenty years. The number 1 will be used where an hypothesis 

 agrees so well with such of the phenomena as are known, that it is 

 concluded that it must either be the true account of them or bear 



