at the Contact of Mutually Reacting Liquids. 535 



Sometimes this arrangement was replaced by a pair of 

 funnels (fig. 2), as described above, carried in holes in the 

 bridge C between the cylinders A, B. A second bridge H, 

 also of paraffin, carried two triple-jet funnels E, F with stop- 

 cocks as shown. The water in each was connected to one 

 terminal of the electrometer-key by means of wires enclosed 

 in glass tubes and joined by platinum wires to the platinum 

 plates m, n. The bridge H could be raised vertically upwards, 

 sliding on the frame of the apparatus, so as to lift the jets 

 clear of the cylinders, thus giving room for the supply of the 

 solutions. This also provided for the reversal of the bridge 

 C, which could be turned end for end ; so that by taking the 

 mean of observations in the two positions, any errors in the 

 funnel part of the arrangement might be eliminated. 



4. To make an experiment with this apparatus, the cylinders 

 having been wetted with the given liquids, one being to earth, 

 and contact between them having been established, the funnels 

 were lowered into position, the stopcocks turned on so as to 

 start the flow of the jets, and the deflexion read in the usual 

 way by two reversals on the electrometer. The flow was 

 then stopped, the funnels raised out of the way, the bridge C 

 reversed, the funnels lowered, re-started, and a second reading 

 taken. A third reading with the bridge C in the original 

 position completed the observation, and the mean of the three 

 readings was taken as the true difference of potential. The 

 results obtained with this apparatus are given in column B, 

 Table II. In this table the formulae represent gramme- 

 molecules ; the affix Aq. represents 1 gramme of water. Column 

 H contains the heat equivalent of the reaction according to 

 Thomsen's data. 



Table II. 





Positive. 



Negative. 



H. 



; A. B. 



1 



9. 



Fe01 o 250 Aq. 



K 2 S 



250 Aq. 



12870 





1-17! 



10. 



FeCl Q 500 „ 



K 2 S 



250 „ 



M 





-11 



11. 



FeCi; 1000 „ 



K 2 S 



1000 „ 







l -18 



12. 



CdCl 2 1000 „ 



K 2 S 



1000 „ 



27150 



f Variable and 

 \ reversing. 



I 



? 



13. 



CdCl 2 1000 „ 



1^2-^2 



1000 „ 



3920 





•07 



•06 



14. 



CdCl 2 2000 „ 



K Q I 2 



2000 „ 



„ 







•03 



15. 



HgCl, 6000 „ 



K 2 I 2 



6000 „ 



26750 









•06? 



16. 



HgOl 2 6000 „ 



K,S 



6000 „ 



46070 







j-08 



17. 



HgCl 2 6000 „ 



k;s 



3000 „ 



„ 







'04 



18. 



Pb01 o 4000 „ 



K 2 S 



4000 „ 



33500 







•10 



19. 



H C1 7000 „ 



BaH 2 0„ 



7000 „ 



27780 







•07 '-096 



20. 



H 2 C1 2 1000 „ 



Na o H 2 2 



1000 „ 



27490 







•003 



21. 



OuCl 2 1000 „ 



Na 2 H 2 2 



1000 „ 



12570 



j Variable and 

 \ reversing. 



1 



1 -10? 



22. 



K 2 L, 



I 2 C1 2 . 





40640? 





•20 



