400 POPULAR LECTURES AND ADDRESSES. 



all show greater resistance to condensation than 

 according to the law of simple proportion, and it 

 seems most probable that there is for every gas 

 a limit beyond which the density cannot be in- 

 creased by any pressure however great. Lane 

 remarks that the density at the centre of the sun 

 would be " nearly one-third greater than that of 

 the metal platinum," if the gaseous law held up 

 to so great a degree of condensation for the 

 ingredients of the sun's mass ; but he does not 

 suggest this supposition as probable, and he no 

 doubt agrees with the general opinion that in all 

 probability the ingredients of the sun's mass, at 

 the actual temperatures corresponding to their 

 positions in his interior, obey the simple gaseous 

 law through but a comparatively small space 

 inwards from the surface, and that in the central 

 regions they are much less condensed than accord- 

 ing to that law. According to the simple gaseous 

 law, the sun's central density would be thirty-one 

 times that of water ; we may assume that it is 

 in all probability much less than this, though 

 considerably greater than the mean density, 1*4, 



