1880.] Thermo-Electric Behaviour of Aqueous Solutions, fyc. 245 



about a quarter of an hour, to remove impurities caused by handling. 

 Repetition experiments were made with each liquid, and, under the 

 above conditions, the results obtained were usually very uniform, the 

 variation of amount of deflection of the needles not often exceeding 

 half a degree. The galvanometer employed was the same as in the 

 research referred to, and was used in the same manner. 



The following are the results obtained with different liquids. 



Behaviour of Different Solutions. 



Experiment No. 1. Twelve ounces of water and 3 grs. of potassic 

 cyanide of a high degree of purity. Hot platinum was positive 1° 

 at 180° F. (Note a.) 



No. 2. A solution (note 6) of 6 grs. of the same salt. Hot platinum 

 positive 2°. 



No. 3. A solution of 60 grs. of the same salt. Hot platinum posi- 

 tive 8£°. 



Note a. All the deflections, except those otherwise stated, were 

 taken at the temperature of 180° F. 



Note b. Unless otherwise described, 12 ozs. of water were used in 

 every case to form the solution, and each solution was made of 

 similar strength to the corresponding one in the research with mer- 

 curial electrodes. 



No. 4. A solution of 120 grs. of the same salt. Hot platinum 

 positive 11°. 



No. 5. A solution of 12 minims of selenic acid (of sp. gr. 1*32 at 

 60° P.). Cold platinum positive J°. 



No. 6. A solution of 24 minims of the same acid. Cold platinum 

 positive 1°. 



No. 7. A solution of 30 grs. of anhydrous selenate of sodium. Hot 

 platinum positive j°. 



No. 8. A solution of 120 grs. of crystalline sulphate of ammonium. 

 Hot platinum positive 3;j\ 



No. 9. A solution of 60 grs. of crystalline amnionic alum. Cold 

 platinum positive |°. 



No. 10. A solution of 120 grs. of the same salt. Cold platinum 

 positive 1°. 



No. 11. A solution of 48 minims of formic acid of sp. gr. 1*18. Hot 

 platinum positive 1°. 



No. 12. A solution of 96 minims of the same acid. Hot platinum 

 positive 1J°. 



No. 13. A solution of 120 grs. of potassic nitrate. Hot platinum 

 positive 1°. 



No. 14. A solution of 120 grs. of crystalline potassic sulphate. 

 Hot platinum positive 4°. 



No. 15. A mixture of seventy-nine volumes of water, and one of 

 pure sulphuric acid. Cold platinum positive 3j°. 



