TWEXTY-SEVENTH ANXLAL MEETIXG. 



109 



The greatest sum in this square is 422.7; the least is 416.6. The differ- 

 ence is 6.1, which is 1.4 per cent, or less than three-fourths of one per cent, 

 on either side of a fixed mean. 



Cesium Hecdecade. 



611.9 



616.1 



614.5 



616.7 



612.8 



615.0 614.5 614.7 616.4 614.9 



The Cesium hecdecade similarly arranged gives results in which the 

 greatest differences are less than one-half of one per cent, on either side of 

 a fixed mean. 



Cesium Hecdecade. 



601.7 601.8 



601.1 



601.2 



601.8 



601.4 



601.3 



601.6 



601.5 601.3 



A rearrangement of the elements of this hecdecade, so as to separate Nd 

 from Ce brings the results so nearly equal that the square is almost per- 

 fectly harmonic. Addition of the corner and central squares, the parallelo- 

 grams, diagonal quadrats, etc., scarcely increases the variation from a fixed 

 mean. 



