590 Emission of Negative Corpuscles by Alkali Metals. 



to the radius of the sphere, leads us to expect that with 

 bodies of the size we could manipulate in the laboratory the 

 differences of temperature would be exceedingly small unless 

 the emission of corpuscles was very copious. It w r ould, 

 however, be interesting to test whether the inside of a block 

 of lime vdiich, as Wehnelt has shown, at high temperatures 

 emits large quantities of corpuscles^ is at such temperatures 

 appreciably hotter than the outside. 



If there is a continual transformation of the internal 

 energy of the atoms into other forms of energy when the 

 atom is emitting corpuscles, we should expect that the 

 internal energy of an atom w r ould vary with the treatment it 

 had received ; that it would have been more diminished if the 

 atom had been maintained for long periods in a state of 

 incandescence than if it had been kept cool ; we should thus 

 expect the internal energy of an atom of an element in the 

 sun to differ from that of the same atom on the earth : if this 

 is so, then this variation in the internal atomic energy must 

 be without effect on some of the properties of the atom. Thus, 

 for example, spectrum analysis shows that the periods of 

 vibration of an atom in the sun do not differ appreciably 

 from those of the same element on the earth ; we have indeed 

 at present no evidence of the existence of any difference in 

 the properties of atoms of the same element. We can, 

 however, easily conceive an atom constructed in such a way 

 that before the internal energy had diminished sufficiently to 

 appreciably alter many of its properties, the atom would 

 become unstable and explode, breaking up into atoms of 

 elements of a different kind. Suppose, for example, that the 

 atom consists of a number of corpuscles arranged in layers 

 on the surfaces of concentric shells, and that the loss of 

 internal energy by the atom is mainly due to the loss of 

 kinetic energy by those corpuscles in the outer layer, this 

 will hardly affect the times of vibrations of the corpuscles 

 inside, while the outer layers may lose such a large amount 

 of energy that their configuration becomes unstable, and the 

 corpuscles in the outer layers rearrange themselves : in doing 

 this, such a large amount of kinetic energy may be liberated 

 that the atom explodes and breaks up into atoms of different 

 kinds. Thus, in a case of this kind we should have the 

 atom losing internal energy and yet as long as it remained 

 intact the great majority of its periods of vibration would be 

 unaltered, and the atom would explode before the change in 

 its internal energy was sufficient to appreciably affect the 

 great majority of its properties. 



