GN VOLTA-ELECTRIC INVERSION. 
297 
being any contact of dissimilar metals. This can be done by 
taking a number of similar cells, heating the alternate ones and 
connecting them in series, but with the connexions in reversed 
order, the copper of one cell being joined to the copper of the 
next, and the iron of one to the iron of the next. The diagram 
explains the connexions. 
9. The only battery which has a true analogy with the above 
is that of Jablochkoff, in which plates of carbon and iron dipping 
into fused nitre yield a current in the reverse direction to that 
in which the current flows with the same electrodes in cells 
containing nitre in aqueous solution. 
In the batteries invented by Louis Napoleon and by Wohler 
there is no contact of dissimilar metals, there being one metal 
and two liquids, with contact of dissimilar liquids. 
In Dr. Fleming’s battery there is neither contact of dis- 
. similar metals nor contact of dissimilar liquids, but there are two 
metals and two liquids. 
