Phenomena of the Capillary Electroscope. 



89 



from 1 in 40 to 1 in 10. Numerous experiments were made with 

 different forms of apparatus, both horizontal and vertical, employing 

 both the feeble current from the water-cell and the charge from the 

 electrophorns. In every case the movement of the mercury was in the 

 same direction as the current and the electric discharge. 



Exp. 19. — 1 oz. of water and 10 grs. of boracic acid. Feeble move- 

 ments occurred in the usual directions with the voltaic current ; but 

 charges from the electrophorus, whether applied to the upper platinum 

 wire or to the lower one, depressed the meniscus freely. (Compare 

 Exp. 14) 



Exp. 20. — With strong aqueous acetic acid feeble effects only were 

 obtained, either with the water-cell or electrophorus, but the move- 

 ments were in usual directions. 



Exp. 21. — 1 oz. of water and 7-5 grs. of racemic acid. Rather feeble 

 movements, but in the usual directions, were obtained, both with the 

 current and the discharge. 



Exp. 22. — Alcohol. No visible movement was produced by the cur- 

 rent from the water-cell, and only a very feeble downward one, by 

 charging the upper electrode with the electrophorus. 



Exp. 23. — 1 oz. of water and 5 grs. of sodic hyposulphite. The 

 solution was too dilute and was otherwise unsuitable. 



Exp. 24. — 1 oz. of water and 5 grs. of ammonic alum. Source of 

 current, the water-cell. The movements were very feeble, but in the 

 usual directions ; and the downward movements were much more quick 

 and were larger than the upward ones. With 10 grs. of the salt per 

 ounce the movements were more free, but the solution was still too 

 dilute. 



Exp. 25. — 1 oz. of water and 5 grs. of potassic sulphite. The effects 

 were exactly the same as with the weakest solution of ammonic alum. 



Exp. 26. — 1 oz. of water and 40 grs. of sulphate of zinc. Free move- 

 ments occurred in the usual directions. 



In the following experiments a drop of dilute sulphuric acid had 

 been previously added to the exciting solution of the voltaic cell. 



Exp. 27. — 1 oz. of water and 40 grs. of cupric sulphate. Similar 

 results occurred to those with the zinc salt. No signs of deposited 

 copper or of viscosity of the meniscus were produced by the upward 

 current. 



The following solutions were also tried : — 1 oz. of water as the 

 solvent, and 40 grs. of the solid were employed in each case ; ammonia 

 alum ; potassic sulphite ; potassic sulphocyanide ; potassic ferro- 

 cyanide ; glacial phosphoric acid ; sodic nitrate ; potassic nitrate ; 

 ammonic nitrate ; and sodic chlorate. Movements in the usual direc- 

 tions occurred in every instance, and no special phenomena were 

 observable. A solution of 40 grs. of potassic ferrid- cyanide produced 

 a film upon the mercury. 



