538 Difference of Potential at the Contact of Liquids. 



Table III. 





Negative to Water. 



Difference of 

 Potential in Volts. 



Heat equivalent. 



93 



H 2 ( 272 )SO 4 ( 40) 



1-58, 1-36, 1-40,1-36. 



17641 c. for 799 H„0. 



24. 



H 2 ( 272 )N 2 6 ( 48 ) 



1-02. 



14986 „ 640 „ 



25. 



H 2 ( 272 )Cl 2 ( 54 )+about4H 2 0. 



•79, -63. 



about 6300,, 300 „ 



?fi 



Zn( 24 )Cl 2( 54 )+5H 2 



•20, -09, -21. 



8020 ,,400 „ 



27. 



Na( 32 ^N 2 6 ( 48 ) + 12H 2 ... 

 Positive to Water. 



•08, -02, -22? 



-4192 „ 400 „ 



28. 



Na 2 ( 32 )H 2 2 ( 143 )+6H 2 ... 



•28, -21. 



5880 „ 200 „ 



29. 



„ sat. solution 



19, diminishing. 



- 



30. 



K 2 ( 52 )H 2 2 ( 143 )+6H 2 ... 



■21, -20. 



5502 „ 200 „ 



31. 



Cu( 29 )Cl 2 ( 54 > sat. solution... 



•15, -07. 



4510 „ 200 „ 



32. 



Cu( 12 )S0 4 ( 4 °) 



•01. 





33. 



+60H 2 O 



03, -03. 



116 „ 200 „ 



34. 



Zn( 12 )SO 4 ( 4 °)+20H 2 O 



•02, -03. 



390 „ 200 „ 



35. 



Na 2 ( 32 )SO 4 ( 4 °)4-50H 2 O ... 



•02. -19. 



-1383 „ 400 „ 



36. 



K 2 ( 52 )N 2 6 ( 48 ) 



Variable, small. 



Probably negative. 



37. 



K 2 ( 52 )C 4 H 6 O 4 ( 26 )4-10H 2 O. 

 Indifferent to Water. 



•05, -03. 



3144 for 400 H 2 0. 



38. 



X 2 ( 52 >C1 2 6 ( 42 ) sat. solution. 



0. 



Probably negative. 



the potential of the slower " ion/'' and in No. 38 there is no 

 sensible difference of potential accompanying the difference 

 of ionic velocity indicated. 



8. Besides these experiments on the contact potential of 

 acids and water, the following three values were obtained be- 

 tween pairs of acids. They are of interest for comparison 

 with the other results. 



Positive. 



Negative. 



D.P. in Volts. 



Nitric Acid 



Hydrochloric Acid Solution 



Sulphuric Acid 



Sulphuric Acid 



•30 

 •92 

 •62 



Nitric Acid 



Hydrochloric Acid Solution 





