1879.] Aqueous Solutions with Mercurial Electrodes. 475 



steadily at 180° F.* Agitation either of the cold mercury (A), or 

 of the hot mercury (B), did not alter the amount of the deflection. 



No. 2. A solntionf of 5 grs. of the cyanide. Cold mercury 

 positive 14°. Agitation either of A or B had no effect. 



No. 3. A solution of 50 grs. of the same salt. Cold mercury 

 positive 45°. Stirring A decreased the deflection temporarily J to 34°, 

 and stirring B decreased it to 9. 



No. 4. A solution of 100 grs. of the same salt. Cold mercury 

 positive 50°. Stirring A decreased the deflection to 41, and stirring 

 B decreased it to 46, 



No. 5. A solution of 10 minims of selenic acid (of sp. gr. 1*32 

 at 60° F.). Hot mercury positive 1J°. Stirring A increased the 

 deflection to 5, and stirring B increased it to 4. There was a simi- 

 larity of behaviour of this liquid to that of dilute sulphuric acid, 

 each exhibited a zero point giving no current at about 120° F. ; but 

 the selenic acid gave a reverse current below that temperature, whilst 

 sulphuric acid did not. 



No. 6. A solution of 20 minims of the same acid. Cold mercury 

 positive 3° at 120° F. Needles at at 143° F., and hot mercury 

 positive 3|° at 180° F. Stirring A decreased the deflection to 1J, and 

 stirring B increased it to 5}. 



No. 7. A solution of 25 grs. of anhydrous selenate of sodium. 

 Hot mercury positive 8°. Stirring A decreased the deflection to 5, 

 and stirring B increased it to 14. 



No. 8. A solution of 100 grs. of crystalline sulphate of ammonium. 

 Hot mercury positive 12^°. Stirring A increased the deflection to 

 29^, and stirring B increased it to 19 J. 



No. 9. A solution of 50 grs. of crystalline ammonic alum. Cold 

 mercury positive 2°. Stirring A increased the deflection to 5J, and 

 stirring B decreased it slightly. 



No. 10. A solution of 100 grs. of the same salt. Cold mercury 

 positive 4°. Stirring A had no effect ; stirring B reversed the deflec- 

 tion 2°. 



No. 11. A solution of 40 minims of formic acid of sp. gr. 1-18* 

 Hot mercury positive 3J°. Stirring A had no effect; stirring B 

 increased the deflection to 7. 



No. 12. A solution of 80 minims of the same acid. Hot mercury 

 positive 5°. Stirring A increased the deflection to 6, and stirring B 

 increased it to 7. 



No. 13. A solution of 100 grs. of potassic nitrate. Hot mercury 



* All the deflections, except those otherwise stated, were taken at the tempera- 

 ture of 180° F. 



+ Unless otherwise described, 10 ozs. of water was used in every case to form the 

 solution. 



£• All the alterations of deflection caused by stirring were only temporary. 



