Atomic Theory — Wilde. 



361 



each other, are obtained by multiplying successively the 

 difference (3) between the distance of the first and second 

 members of the system by a geometric series, and adding 

 to the products the constant distance (4) of the first mem- 

 ber from the sun. 



' If the atomic weight of the second member of the 

 alkaline and silver group of metals (Na = 23) be multiplied 

 successively by an arithmetical series, then will the products, 

 minus the atomic weight of the first member (Li = 7), be 

 the atomic weights of all the elements belonging to that 

 group. 



II. 



o* o- 7 = Li = 7 

 I X 23 -o =Na = 23 

 2x23-7 = Ka = 39 

 3 X 23 — 7 = Cu = 62 

 4x23-7 = Rb = 85 



5x23-7 = Ag=io8 

 6 X 23 — 7 = Cs =-131 

 7x23-7= =154 

 8x23-7= =177 

 9 X 23 — 7 = Hg = 200 



* Again, by multiplying in like manner the atomic weight 

 of the second member of the alkaline earth and cadmium 

 group of metals, the products, minus the atomic weight of 

 the first member (Gl = 8), are the atomic weights of all the 

 elements of this group. 



III. 



o- o- 8= Gl = 8 



1 X 24 -o = Mg = 24 



2 X 24 — 8 = Ca =40 



3 X 24 — 8 = Zu =64 



4x24-8-=Sr =88 



5 X 24 — 8 = Cd = 112 



6 X 24 — 8 = Ba = 136 

 7x24 — 8= =160 

 8x24 — 8= =184 

 9 x 24-8 = Pb =208 



* The further relations observable between interplanetary 

 voids and atomic condensations of the natural groups of 

 elements in Tables II., III., are as follows : — 



* I. The regular geometric series of the planetary dis- 

 tances commences at the second member of the system, 

 and the regular arithmetical series of atomic weights com- 



