ATOMIC DISINTEGRATION. 151 



Since the mass of the corpuscles is a thousand times 

 smaller than the mass of any known atom, we see that the 

 corpuscle must be a constituent of all substances, that as 

 a matter of fact, the atoms of all the elements must have 

 corpuscles in common. We are in this way face to face 

 with the idea that the atoms of the chemical elements are 

 actually built up of corpuscles. Evidence in support of 

 this hypothesis is not wanting. For example, on page 72 

 of Part III of our work will be found the law of absorption 

 for corpuscles, in which it is apparent that the resistance 

 which substances interpose to the passage of corpuscles 

 through them, in other words, their opaqueness, depends 

 solely upon the density of the substance. If one substance 

 is twice as heavy as another it is only half as transparent 

 to corpuscles. The particular kind of matter has nothing 

 to do with it. How different substances act towards light 

 waves may be seen in the case of cork which is just as 

 opaque as iron. It is all easily explicable on the theory we 

 are considering. If each atom of matter is built up of 

 corpuscles and if these corpuscles are extremely minute 

 compared with the atom as a whole, it is evident enough 

 that we must look upon an atom as an open structure in 

 which the vacant spaces are enormous compared with the 

 size of the tiny corpuscles scattered throughout the atomic 

 system. We may, with Lodge, illustrate the relation of a 

 corpuscle to the atom which it inhabits, thus : 



If we imagine an ordinary church to be an atom of hy- 

 drogen, the corpuscles constituting it will be represented 

 by about 1000 grains of sand each the size of a period so . , 

 dashing in all directions inside or rotating with inconceiv- 

 able velocity, and filling the whole interior of the church 

 with their tumultuous motion. Such an atom would be 

 penetrable to other corpuscles in inverse proportion to the 



