Chemical Affinity in terms of Electromotive Force. 281 



that acid of 1*2207 sp. gr. containing 30 per cent, of H$>S0 4 , 

 and therefore containing in 100 cubic centims. 36*6 grammes 

 of H 2 S0 4 , has a specific resistance of 1*37 ohm at 18°, 

 whilst acid of sp. gr. 1*2625, containing 35 percent., or 44*2 

 grammes per 100 cubic centims., has the specific resistance 

 1*40 ohm at 18° ; whence evidently the specific resistance of 

 acid of 40 grammes per 100 cubic centims. strength may 

 be taken as 1*385 ohm at 18°, or close to 1*4 ohm, nearly 

 the same as for acid of strength equal to 27*0 grammes per 100 

 cubic centims. (the minimum specific resistance being known 

 to be at strength intermediate between 30 and 35 grammes 

 per 100 cubic centims.) ; so that R is, as before, close to 

 12*1 ohms. 



Current, in 

 mierowebers. 



Mierowebers per j 



square centimetre of j 



electrode surface, j 



E, in volts. 



CR. 



<?=E-CR. 



3-1 



0-11 



1-564 





1-564 



4-0 



0-14 



1-663 





1-663 



O'O 



0-20 



1-761 





1-761 



8-6 



0-31 



1-801 





1-801 



13-6 



0-49 



1-843 





1-843 



21-2 



0-77 



1-891 





1-891 



47-1 



1-71 



1-972 



•001 



1-97.1 



76-3 



2-77 



2-034 



•001 



2-033 



204-0 



742 



2105 



•002 



2-103 



281-0 



10-2 



2143 



•003 



2-140 



370-0 



13-4 



2-181 



•005 



2-176 



6790 



24-7 



2-223 



•008 



2-215 



11400 



41-4 



2-303 



•014 



2-289 



i 



Acid containing 11*4 grammes of 

 centims. — Voltameter No. 3 employed, 

 from Kohlrausch's determination of sp. 



acid= -— j — =13*6 ohms. 



H 2 S0 4 per 100 cubic 



Value of R calculated 



resistance * of sulphuric 





Mierowebers per 









Current. 



square centi- 

 metre. 



E. 



CE, 



e = E-CR. 



6-8 



2-1 



2-125 





2-125 



9-8 



31 



2-156 





2-156 



12-3 



4-0 



2-218 





2-218 



16-9 



5-3 



2-256 





2-256 



29-0 



9-0 



2-297 





2-297 



45-8 



14-3 



2-340 



•001 



2-339 



70-1 



21-9 



2-362 



•001 



2-361 



109-9 



344 



2-420 



•002 



2-418 



212-0 



66-2 



2-486 



•003 



2-483 



306-6 



94-8 



2-529 



•004 



2-525 



* Acid of 1-0673 sp. gravity containing 10 per cent. H 2 S0 4 , corre- 

 sponding to 10-7 grammes per 100 cubic centims., gives sp. resistance at 



