154 



SCIENCE. 



[X. S. Vol. XXI. Xo. 526. 



rods are placed sixteen wooden balls, eight on 

 each rod as shown in the sketch. Across the 

 top of the supports is fastened the horizontal 

 scale, 88. This scale is divided into sixteen 

 equal parts, the value of each division being 

 the same as the diameter of a ball, or 28 mm. 

 Between the third and fourth divisions, and 

 between the twelfth and thirteenth divisions 

 are placed two light strips of wood as shown 

 at BB and CC. From the eighth division to 



To make its use clearer let us take a con- 

 crete case. Suppose the anion of the elec- 

 trolyte to have a velocity twice as great as 

 the velocity of the kation. Placing the balls 

 as shown in Fig. 1 with the wire DD bisecting 

 the two rows, we move the middle of the lower 

 row, the anions, from division 8 to division 10. 

 We then move the upper row from division 8 

 to division 7.' We have thus imparted a ve- 

 locity to the anions twice as great as that 



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the base-board is stretclied a vertical wire, DD, 

 1 mm. in diameter. The upper row of balls 

 are painted black and are chosen to represent 

 kations ; the lower row are painted white and 

 represent anions. The strip BB is painted 

 black, representing the kathode, and the strip 

 CC is painted white, representing' the anode. 

 The wire DD represents the trace of an im- 

 aginary plane of reference through the solu- 

 tion. 



With this arrangement it is possible to dem- 

 onstrate to a class Ilittorf's theory as ex- 

 ])lainod by Ostwald.* 



* ' Letiil). (I. Allg. Chem.,' II., 595. 



imparted to the kations. Now let three mole- 

 cules discharge, the ions assuming the atomic 

 or molecular condition. To represent this we 

 move the three end ions beyond the electrodes 

 BB and CC, when we have the condition' rep- 

 resented in Fig. 2. It is obvious that the 

 ratio of the kathode loss to the total number 

 of molecules electrolyzed is 2:3, and the ratio 

 of the anode loss to the total number of mole- 

 cules electrolyzed is 1:3. These two values 

 bear the same relation to eacli other as the 

 velocities of anion and kation. 



By varying the conditions it is possible to 



