478 Dr. G. Gore. Thermo- Electric Behaviour of [Dec. 15, 



Amount of deflection. 



12. Mtrate of barium 7'5 



13. Mtrate of sodium 1 6'0 



14. Forniiate of sodium (100 grs.) J 6'0 



15. Microcosmic salt (50 grs.) ) 5'0 



16. Formic acid (80 minims) / 5*0 



17. Nitrate of ammonium 4*25 



18; Formiate of sodium (50 grs.) 4*0 



19. Selenic acid (20 minims) 375 + 



20. Formic acid (40 minims) 3*5 



21. Sulphate of sodium ) 2*5 



22. Sulphite of sodium (10 grs.) J 2'5 



23. Microcosmic salt (100 grs.) ") 2*0 



24. Boracic acid J 2*0 



25. Selenic acid (10 minims.) 1*5 



26. Sulphuric acid (1 in 80) 1*25 — 



27. Ammonia alum (50 grs.) 1 2*0 



28. Cyanide of potassium (2J grs.) / 2 - 



29. Hyposulphite of sodium 1 4*0 



30. Ammonia alum (100 grs.) / 4'0 



31. Sulphuric acid (1 in 20) 6*25 



32. Sulphuric acid (1 in 40) 675 



33. Sulphite of potassium 9*0 



34. Cyanide of potassium (5 grs.) 14*0 



35. Cyanide of potassium (50 grs.) 45*0 



36. Cyanide of potassium (100 grs.) 50*0 



To ascertain whether this order agreed with that of a series arranged 

 according to the different degrees of electromotive force of the various 

 couples, I simultaneously employed two apparatuses similar to that 

 already described (but ^vith basins of 75 millims. internal diameter), 

 charging one of them with one solution, and the other with another 

 whicli was next to it in the above series, connecting them with the 

 two wires respectively of the differential galvanometer, so that their 

 currents circulated in opposite directions through the coil of that in- 

 strument, and ascertaining which gave the strongest current at 

 160° F. By this means the following series was obtained, in which 

 the couple giving the strongest positive current is at the top, and that 

 giving the most powerful negative current at the bottom, as in the 

 previous list. The horizontal line separates those liquids in which the 

 hot metal was positive from those in which it was negative. The 

 relative positions of the solutions in the two series, although they 

 agree in the main, are not identical ; for instance, nitrate of potassium 

 occupies the eighth place in the first series, and the second place in 



