THE MAGIC SQUARE. 



Knaves, that in each horizontal, vertical, and diagonal row. each 

 one of the four suits and each one of the four denominations shaii 

 appear once and once only. The auxiliary squares above given fur- 

 nish the appended solution of this problem : 



Fig. 21. 



To fix the solution of the problem in the memory, observe that, 

 starting from the several corners, each suit and each denomination 

 must be placed in the spots of the move of a Knight. If we fix the 

 positions of the four cards of any one row, there will be only two 

 possibilities left of so placing the other cards that the required con- 

 dition of having each suit and each denomination once and only 

 once in each row shall be fulfilled. 



Of magic squares of an even number of places we have up to 

 this point examined only the squares of 4 and of 6. For the sake of 

 completeness we append here one of 8 and one of 10 places. The 

 mode of construction of these squares is similar to the method above 

 discussed for the lower even numbers. 



Fig. 22. 



