1905.] on the Structure of the Atom. 58 



atoms resemble the properties of the chemical atom. I will take the 

 electro-chemical property of the atom. Some atoms, such as those of 

 hthium, sodium, potassium, have a strong tendency to be positively 

 electrified, while others like chlorine, bromine, iodine, tend to be 

 negatively electrified. Now the way our model atom gets positively 

 electrified, is by losing a negatively electrified corpuscle ; thus, those 

 atoms in which the corpuscles are loosely held would tend to get posi- 

 tively electrified, while those whose corpuscles are very firmly held 

 would not get positively electrified, and might be able to bear the dis- 

 turbance due to another corpuscle placed outside without disintegration, 

 and with this additional corpuscle they would be negatively charged. 

 Now let us see how this property would vary from atom to atom. I will 

 take a numerical case. Suppose we begin with 5*.) corpuscles ; we should 

 have by the table 20 on the outside, and 39 in the inside ; but as o9 

 is the least number of corpuscles that can hold a ring of 20 in stable 

 equilibrium, the equilibrium of this atom would have nothing to spare ; 

 it would be in rather a tottery condition, and a corpuscle would be easily 

 detached, leaving the atom positively charged. Let us now go to the 

 atom with 60 corpuscles ; it would still have 20 on the outside, but it 

 would have 40 on the inside, and be more stable than 59 ; it would 

 not so easily lose a corpuscle ; and would not thus be so electro-positive 

 as 59 ; as we go on up to 67 we have still 20 on the outside but 

 get more and more in the inside, the difficulty of getting a corpuscle 

 out therefore increasing, and the atom getting more and more electro- 

 negative. Let us see what happens when we get to 68 ; here we have 

 21 on the outside and 47 inside, but as 47 is the smallest number 

 w^hich can keep 21 in equilibrium, this equilibrium is shaky, and as in 

 the case of 59 corpuscles the atom would be very electro-positive. 

 Thus, as we increase the atomic weight, we get for a certain range, a 

 continual diminution in the electro-positive character ; this goes on 

 until we get to 67, then there is a sudden jump from the electro- 

 negative 67 to the electro-positive 68, followed again for a time by a 

 continual decrease in electro-positive characteristics with increasing 

 atomic weight. Compare this with the behaviour of the atoms of the 

 chemical elements 



Li Bi Bo C N Fl 



Na Mg Al Si P S CI 



K — — 



The electro-positive character diminishes as we proceed from Li 

 to Fl, then there is a sudden change from the electro-negative Fl 

 to the electro-positive Na, then another diminution in the electro- 

 positive character to CI, and then another sudden change from CI 

 toK. 



The model atoms we are considering are all built up of the same 

 materials — positive electricity and corpuscles — hence the atoms of any 

 one element would furnish the raw materials for the atoms of any other 

 element, and a rearrangement of the positive electricity and corpuscles 



