ORIGIN AND AGE OF THE SUNS HEAT. 283 



particles have existed in this separate form when 

 devoid of the repulsive energy of heat, seeing that, in 

 virtue of gravitation, they had such a tendency to 

 approach one another? 



It will not do to begin with the assumption of a cold 

 nebulous mass, for, the moment that the mass existed as 

 such, condensation — under the influence of the mutual 

 attraction of its particles — would commence. We must 

 therefore assume either that the mass was created at 

 the moment condensation began, or that, prior to this 

 moment, it existed under some other form. There are 

 few, I think, who would be willing to adopt the former 

 alternative. If we adopt the latter we must then ask 

 the question, In what condition did this mass exist 

 prior to the commencement of condensation ? The 

 answer to this question would naturally be that it 

 existed in a condition of excessive temperature, the 

 repulsive force of heat preventing the particles 

 approaching one another. In short, the excessive 

 temperature was the very cause of the nebulous 

 condition. 



But if the mass was originally in a heated condition, 

 then in condensing it would have to part not only with 

 the heat of condensation, but also with the heat which 

 it originally possessed. 



It is therefore evident that if we admit that the 

 nebulous mass was in a state of incandescence prior to 

 condensation, it will really be difficult to fix any limit 

 either to the age of the sun or to the amount of heat 

 which it may have originally possessed. The 20 million 

 years' heat obtained by condensation may in such a 

 case be but a small fraction of the total quantity 

 possessed by the mass. 



How the Mass obtained its Temperature. — The ques- 

 tion now arises, By what means could the nebulous 



