ATOMIC DISINTEGRATION. 163 



shown, on mathematical grounds, that such related groups 

 of corpuscles would of necessity possess related spectra 

 such as have lately been discovered among the elements of 

 certain groups in the table of the periodic law. This is a 

 strong confirmation of our theory. 



SERIES RELATIONS. 



But the atoms of matter as they appear in the table of 

 the periodic law are related not only in groups but in 

 series, (page 29). A series is a horizontal row of ele- 

 ments in the table as a group is a vertical one. The 

 gradual change in the properties of the elements which 

 takes place as we travel along one of these horizontal rows 

 is also illustrated in the properties possessed by these groups 

 of corpuscles. To demonstrate this, consider, for example, 

 the series of arrangements of the corpuscles given on page 

 158, in all of which the outer ring contains 20 corpuscles. 

 An outer ring containing 20 first occurs in a group of 59 

 corpuscles. Professor Thomson shows that in this case 

 of 59 corpuscles the number of corpuscles inside is only 

 just sufficient to make the outer ring of 20 stable; this 

 ring will, therefore, be on the verge of instability and when 

 its corpuscles are displaced, the forces urging them back 

 again will be small. 



For this reason, when the ring is subjected to an exter- 

 nal disturbance, one or more corpuscles may easily be de- 

 tached from it. We must remember, though, that in these 

 collections of corpuscles, the negative electricity of the 

 collection is exactly balanced by the sphere of positive 

 electricity surrounding it and enclosing it; and, hence, if 

 one negative corpuscle is lost the whole arrangement will 

 assume a positive charge. Such an atom would behave 

 like the atom of a strongly electro-positive or basic element. 



