﻿Dr. Paalzow on the Galvanic Resistance of Liquids. 273 



was possible ; for, from the difference of the liquid resistances, by 

 the aid of the mercurial resistances the entire resistances of the 

 liquids in the siphon tubes could be calculated without the 

 accessory magnitudes. Deducting these resistances from the 

 observed values, the difference represented the magnitude which 

 was due to the resistance of the conducting vessels and the in- 

 equality and polarization of the electrodes. In one and the same 

 experiment this magnitude must be the same for all the siphon 

 tubes used. 



By this method I have investigated aqueous solutions of 

 sulphuric acid, sulphates of zinc, copper, and magnesium, and 

 hydrochloric acid. I am indebted to Dr. Rudorff for the che- 

 mically pure solutions of known strength. The observations 

 were made at the temperature of the room. 



Sulphuric Acid. 





Temperature. 



Resistance as compared 

 with mercury. 



H 2 SO< 



H 2 SO+ 14H 2 

 H 2 S0 4 -f- 13H 2 

 H 2 S0 4 +499H 2 ' 



15 C. 

 19 

 22 

 22 



96950 



14157 1 tvt- • 



13310 Minimum. 

 184773 



Sulphate of Zinc. 



ZnSOH 38H 2 

 ZnS0 4 + 24H 2 

 ZnSO 4 +107H 2 O 



23 C. 



23 



23 



194400 

 191000) w ■ 

 354000J Mimmum - 



Sulphate of Copper. 



CuS0 4 + 45H 2 

 CuSO 4 +105H 2 O 



22 C. 

 22 



202410 

 339341 



Sulphate of Magnesium. 



MgS0 4 + 34 IPO 

 MgSO 4 +107H 2 O 



22 C. 



22 



199180 

 324600 



Hydrochloric Acid. 



HC1+ 15H 2 

 HC1+500H 2 



23 C. 



23 



13626 

 86679 



Although I have examined the acids and salts in question 

 Phil. Mag. S. 4. Vol. 37. No. 249. April 1869. T 



