the TJiermo-Electric Properties of Liquids. 



519 



and the lower plate was at the atmospheric temperature, .varying from 

 55° to 65° F. In all instances where the temperature is not specified, 

 the upper plate was at 210° F. Distilled water was used in making 

 all the various solutions, unless otherwise stated. 



Experiment No. 1. 14 oz. by measure of water and 1 oz. of a satu- 

 rated solution of pure sodic carbonate. Platinum plates. Galvanometer 

 of 25 ohms resistance. Current J, hot plate positive, deflection "25°. 



No. 2. 7 oz. of water and 7 oz. of the same saturated solution. Pla- 

 tinum plates. Current J 7' 5. 



No. 3. 1 oz. of water and 14 oz. of the same saturated solution. 

 Platinum plates. Current J 10. 



No. 4. Same mixture as in No. 3. Platinum plates. Galvanometer 

 of 100 ohms resistance.* Current J 15. (Compare Nos. 39 and 118.) 



No. 5. The same mixture. Silver plates. Current J 15*75. 



HemarTcs. No sign of corrosion of the plates appeared in either of 

 these five experiments. The current increased in magnitude with the 

 strength of the solution. 



No. 6. The same mixture. Copper plates. Current \ 65*5. The 

 upper plate was found corroded after this experiment. (Compare 

 No. 164.) 



No. 7. Upwards of forty different experiments were made with pure 

 dilute sulphuric acid of seven different degrees of strength, varying 

 from 12 oz. of water and 3 oz. of the acid to 14 oz. of water, and 

 ■Yz oz. of the acid ; and all the mixtures were tried with plates of pla- 

 tinum, gold, and palladium. The current was upward in every case, 

 and the amount of deflection varied from 1-J° to 45°. (Compare Nos. 

 115, 116, and 117.) The currents were reverse in direction to those 

 which would have been produced by chemical action ; and were 

 strongest with that metal which was the least likely to be chemically 

 affected, viz., platinum. 



No. 8. 14 oz. of water and J oz. of sulphuric acid. Silver plates. 

 Current J 20'5. 



No. 9. 14 oz. of water, and ^ oz. of sulphuric acid. Silver plates. 

 Current f 32. 



No. 10. 14 oz. of water and 3 oz. of glacial acetic acid, or 14 oz. of 

 water, and either J oz. or ^ oz. of the acid ; each mixture being used 

 with palladium plates gave very feeble current { ; and then, on suddenly 

 applying much cold water to the hot plate, a less feeble \ current was 

 produced. Platinum and gold plates gave similar effects with a mix- 

 ture of 14 oz. of water and -J oz. of the acid. 



No. 11. 14 oz. of water and -J oz. of thick syrupy solution of ordi- 

 nary phosphoric acid. Platinum, gold, and palladium plates. Cur- 

 rent \ about '5. Cold water then applied produced in each case a 

 feeble J current. 



* This galvanometer was used in all the subsequent experiments. 



