SULPHURET OF POTASSIUM,— VOLTAIC CIRCLES. 
87 
proper character, and as iron or nickel would do in the place of the lead, then the 
force there would be 21, whereas it is less, or according' to the assumed 
numbers only <== 10. Now as there is no reason why the lead should have any 
superiority assigned to it over the solution, since the latter can give a balanced con- 
dition amongst good conductors in its proper situation as well as the former ; how 
can this be, unless lead possess that strange character of sometimes giving equipoised 
contacts, and at other times not (1865.). 
1892. If that be true of lead, it must be true of all the metals which, with this sul- 
phuretted electrolyte, give circles producing currents; and this would include bismuth, 
copper, antimony, silver, cadmium, zinc, tin, &c. &c. With other electrolytic fluids 
iron and nickel would be included, and even gold, platinum, palladium ; in fact all the 
bodies that can be made to yield in any way active voltaic circuits. Then is it pos 
sible that this can be true, and yet not a single combination of this extensive class of 
bodies be producible that can give the current without chemical action (1867-), con- 
sidered not as a result, but as a known and pre-existing force ? 
1893. I will endeavour to avoid further statement of the arguments, but think my- 
self bound to produce (1799.) a small proportion of the enormous body of facts which 
appear to me to bear evidence all in one direction. 
1894. Bismuth. — This metal when associated with platinum, gold, or palladium in 
solution of the sulphuret of potassium, gives active circles, the bismuth being positive. 
In the course of less than half an hour the current ceases ; but the circuit is still an 
excellent conductor of thermo currents. Bismuth with iron or nickel produces the 
same final result with the reservation before made (1826.). Bismuth and lead give 
an active circle; at first the bismuth is positive; in a minute or two the current 
ceases, but the circuit still conducts the thermo current well. 
1895. Thus whilst sulphuret of bismuth is in the act of formation the current is 
produced ; when the chemical action ceases the current ceases also ; though contact 
continues and the sulphuret be a good conductor. In the case of bismuth and lead 
the chemical action occurs at both sides, but is most energetic at the bismuth, and 
the current is determined accordingly. Even in that instance the cessation of che- 
mical action causes the cessation of the current. 
1896. In these experiments with lead and bismuth I have given their associations 
with platinum, gold, palladium, iron, and nickel ; because, believing in the first place 
that the results prove all current to depend on chemical action, then, the quiescent 
state of the resulting or final circles shows that the contacts of these metals in their 
respective pairs are without force (1829.) : and upon that again follows the passive 
condition of all those contacts which can be produced by interposing other conducting 
bodies between them (1833.) ; an argument that need not again be urged. 
1897. Copper. — This substance being associated with platinum, gold, iron, or any 
metal chemically inactive in the solution of sulphuret, gives an active circle, in which 
the copper is positive through the electrolyte to the other metal. The action, though 
