405 
electrical and chemical changes. 
with respect to all those below it. This law extends likewise 
to the newly discovered bases of the alkalies and earths. 
Potassium and sodium, as I have found by bringing them in 
contact with zinc in a concentrated solution of alkali, are 
apparently as much positive with respect to this body, as zinc 
is with respect to platinum and gold. 
There is not however any inherent and specific property 
in each metal which gives it the electrical character ; it de- 
pends upon its peculiar state— on that form of aggregation 
which fits it for chemical change. Thus, zinc in amalgamation 
with mercury is positive with respect to pure zinc, and the 
amalgam of tin is in the same state with regard to tin ; and 
the metals of the fixed alkalies in amalgam give the highest 
positive energy to a mass of mercury some thousands of 
times their weight. 
In general, the electricities developed by metallic contact 
are of a stronger kind than those resulting from the contact 
of metals with fluids, so that they are not capable of being 
changed by them. For instance : zinc in acid is positive with 
respect to all other metals below it in degree of oxidability, 
though they are placed in alkalies or solutions of sulphurets : 
there are however exceptions ; for instance, with regard to 
tin, which, when in a strong solution of potassa is positive to 
zinc in an acid solution ; and with respect to iron, which, 
though positive with regard to copper in all acid or neutro- 
saline fluids, is negative to it in solution of sulphurets or of 
alkalies. The electro-motion in these instances produced by 
the contact of the fluids prevailing over that produced by the 
contact of the metals. 
3 G 
MDCCCXXVI. 
