The DuLuc Dry Pile
The Duluc Dry-Pile (also called the Zamboni Pile) was an "electrostatic
battery" permanent power supply used in the early 1800s and constructed
from silver foil, zinc foil, and paper. Foil disks of 2cm dia. were
stacked up several thousand thick and then either compressed in a glass
tube with endcaps and a screw assembly, or stacked between three glass
rods with wooden endplates. Of course this is simply a Voltaic Pile, a
multi-cell electrochemical battery, albiet one with output potential in
the range of kilovolts. Each cell used nearly-dry paper as electrolyte,
with zinc foil for one electrode and silver foil as the other.
PERPETUAL MOTION, The History of an Obsession, by Arthur Ord-Hume, St.
Martin's Press, NY 1977, ISBN 0-312-60131-X
STATIC ELECTRICITY with 30 experiments, by J.H. Pepper, Lindsay
Publications, Bradley IL, pp246-248
BEHRENS ZINC/COPPER/FLINT PILE ANNALEN DER PHYSIK, vol. 23 1 1806 ZAMBONI PILE M. J. Jamin, COURS DE PHYSIQUE, Gauthier-Villars, Paris, 1869, 2nd Ed., Vol 3, p39 Brugnatelli, GIORNALE DI FISICA... DEL RIGNO ITALICO, vol. 5, Dec. 1812 pp 424-46 DULUC PILE BY G.J. Singer, detailed instructions ELEMENTS OF ELECTRICITY AND ELECTROCHEMISTRY, London 1814 PRACTICAL CONSTRUCTION INSTRUCTIONS ENGLISH MECHANIC 1915 TH. Pratt and A. Elliott, ELECTRONIC ENGINEERING, Sept 1948 and Oct 1948 (w/info about WWII IR viewers powered by dry-piles)
If the Franklin's Bell constitutes a capacitance of maybe 5 picofarad
(5E-12 Farad,) and if it is connected to a 1KV constant voltage battery,
how small must the battery's internal resistance be in order to recharge
the capacitance of the bell device several times per second? The
minimum resistance in ohms may suprise you, it is very high and should
easily be achieved even by a stack of non-moist paper disks. A Dry Pile
won't run if its paper is totally dessicated, but usual environmental
humidity is enough to keep it working.
A 1.5v AA cell can provide about .5 ampere for 1 hour before being
exhausted. If the Dry Pile has about the same energy density as a
double-A cell and is about 30 times larger in volume, how long will it
be able to operate the Franklin's Bell at a recharge rate of several
times per second? The answer in years is impressive. These devices
were called "Electric Perpetum Mobile." While not truly perpetual,
they could outlast their creators by quite a few centuries!