The Science Book

94 ALESSANDRO VOLTA

Britain. The letter was titled
“On the electricity excited by
the mere Contact of conducting
Substances of different Kinds,” and
in it Volta describes his apparatus:
“I place then horizontally, on a
table or any other stand, one of the
metallic pieces, for example one of
silver, and over the first I adapt one
of zinc; on the second I place one of
the moistened discs, then another

plate of silver followed immediately

by another of zinc...I continue

to form...a column as high as

possible without any danger of

its falling.”

Without a buzzer or a

semiconductor to detect voltage,

Volta used his body as a detector,

and did not seem to mind getting

electric shocks: “I receive from a

column formed of twenty pairs of

Volta demonstrated his electric

pile to Napoleon Bonaparte at the

French National Institute in Paris

in 1801. Napoleon was sufficiently

impressed to make Volta a count

the same year.

pieces (not more) shocks which

affect the whole finger with

considerable pain.” He then

describes a more elaborate

apparatus, consisting of a series

of cups or drinking glasses, each

containing salt water, arranged

in a line or a circle. Each pair is

connected by a piece of metal that

dips into the liquid in each cup.

One end of this metal is silver, the

other zinc, and these metals may

be soldered together or connected

by a wire of any metal, provided

that only the silver dips into the

liquid in one cup, and only the zinc

into the next. He explains

that this is in some ways more

convenient than the solid pile,

albeit more cumbersome.

Volta describes in detail the

various unpleasant sensations

that result from putting one hand

in the bowl at one end of the chain

and touching a wire attached to

the other end to the forehead,

eyelid, or tip of the nose: “I feel

nothing for some moments;

afterward, however, there begins at

the part applied to the end of the

wire, another sensation, which is a

sharp pain (without shock), limited

precisely to the point of contact, a

quivering, not only continued, but

which always goes on increasing

to such a degree, that in a little

time it becomes insupportable,

and does not cease till the circle

is interrupted.”

Battery mania

That his letter reached Banks

at all is surprising, since the

Napoleonic wars were in progress,