108 On the Conduction of Electricity in Electrolytes. 



obtain tlie negative work of the countei'-pressure by multiplying 

 the volume of the liquid by this pressure. 



In order to obtaiu an approximate estimate of the values of 

 these quantities of work, we will, as an example, assume that the 

 driving force is sufficiently great to overcome a hydrostatic coun- 

 ter-pressure of a whole atmosphere. This force, expressed in 

 kilogrammes to a square metre, is then 10333, and in order to 

 obtain the work, expressed in kilogramme-metres, we must mul- 

 tiply the above number by the volume of the liquid driven 

 through the partition and expressed in cubic metres. For 

 instance, if, during a given time, a litre or O'OOl cubic metre is 

 driven through the partition, the corrcspondong work will be 



10333 . 0001 = 10-333 kilogramme metres. 



This work, if converted into heat, would give 



10-333 1 p - fi , 



-— — -— = — r 01 a unit 01 heat. 

 433-55 41 



consequently as much heat as would raise the temperature of a 

 litre of water, weighing a kilogramme, 



— r of a degree C, 



or that of a litre of the liquid driven through 



— r of a degree C, 



41 . c . s 



where c is the specific heat, and s the specific gravity of the liquid. 

 This result, in which definite values have been assumed merely 

 for the sake of simplicity, may be immediately generalized. Let 

 p represent the force with which the liquid is driven through the 

 partition, the same being conceived to be replaced by a hydro- 

 static pressure and expressed by atmospheres; then the work 

 done by this force in driving a given volume of the liquid through 

 the partition, would, if converted into heat, raise the tempera- 

 ture of the volume of liquid in question 



-^ — degrees C. 

 41 .c.s 



This work is so small, that it can form but a small portion of 

 the whole work done by the electric force within the porous par- 

 tition. In badly-conducting liquids only can it be, compara- 

 tively, more considerable, since with the same strength of current 

 a greater quantity of a bad than of a good conducting liquid 

 passes through the partition. 



From the connexion which exists between the motion of elec- 

 tricity and that of a liquid through a porous partition, it appears 



