142 



Lord Kelvin on 



fig. 2 ; and for brevity denote X */§ by /e. The distances 

 from A of all the neighbours around it are : — 



In our "middle plane " : 6 each equal to q l : 6, q 2 ; 6. q % ; 

 ^% 9+', 6, g 5 ; 



In the two parallel nets at distances /e from middle : 6 

 each equal io ^(j? + r ?) ; 6, V(/e 2 4-r, 2 ); 12, i/(« 2 + r, 2 ) ; 

 12, V(« 2 + r 4 2 ); b\ ,/(« 2 4-r 5 2 );12, V(> 2 + ?Y0; 6, V(« 2 + ^: 2 ). 



In the two parallel nets at distances 2k from middle : the 

 same as (B) altered by taking 2k everywhere in place of k. 



Fie-. 2. 



In the two parallel nets at distances 3k from centre : the 

 same as (A) altered by taking -v/(9/c 2 + gi 2 ), s/(9/c 2 + ^ 2 2 ), etc., 

 in place of q^ q 2 , etc. 



In nets at distances on each side greater than 3k : distances 

 of atoms from A, found as above, according to the cycle of 

 atomic configuration described in (e) of § 6. 



§ 8. By geometry we find 



qi =\; q 2 = V3A = l-732\; q 3 =2\ ; q±= V7X=2«646X ; q 5 =3\: 

 r x = V^X=-577X; r 2 =2 V|X = M54X; r 3 = ViX = r527X; r 4 = 

 r g =4V§X=2'308\ ; r 6 = VyX=2-517X; r 7 =5 VfX-=2-887X. 



WX = 2-082X: j-(4). 



J 



