Before consideringelectrical horology, let's take a quick glance at thehistory of electricity and magnetism.
Mankind has know electric effects in the form of lightning from the earliest
times but the nature of these effects was of course unknown to him. Sailors
were sometimes startled to see a flickering luminous light at the tips of
a ship's mast and spars: the famous Saint Elmo's fire.
The first man-made electricity was discovered by the rubbing of amber. Amber,
a pale yellow translucent fossil, has the ability to attract light objects
such as paper and feathers when it is rubbed.
Some 3,000 years B.C. the Chinese were already aware that lodestone, a magnetic
oxide of iron, attracts small pieces of iron. The Chinese were also aware
of lodestone pointing to the North Pole and used it for navigational purposes.
In 1600 William Gilbert (1540-1603), physician
to Queen Elisabeth and King James, was the first to explain the nature of
magnetism. In his book "De Magnete" he called the mysterious forces
involved: "electrics". This illustration shows how hot steel was
magnetized by hammering it while held in the magnetic meridian.
In 1660 Otto von Guericke (1602-1686) was the
first to make a machine producing electricity.
Von Guericke is also well known for his invention of the vacuum air pump
and his famous experiment with the Magdeburg hemispheres in 1654.
By rotating a globe of sulphur, it is electrically excited by the friction
of a hand held against it. The globe could be carried about to attract,
and repel, light objects such as paper and feathers.
effect is now known to us as static electricity, meaning very high voltage but
of extreme low power.
.Pieter van Musschenbroek
(1692-1761), a Dutch physicist, was engaged in a research to determine
the strength of electricity. In doing so, he probably was the first to experience,
quite accidentally, the discharge of a Leyden jar through the human body.
the invention of the Leyden jar electricity could now be stored in large quantities,
held sometimes for days, and discharged at will.
In 1678 Jan Swammerdam (1637-1680), a Dutch microscopist
, demonstrated the contraction of a dissected frog's leg when its nerve is touched by a metal
was not until 1786 that Luigi Galvani (1737-1798),
professor of anatomy
at Bologna, explained this phenomenon by the production ofa
"nerveo-electrical" fluid similar to that of frictional electricity.
Alessandro Volta (1745-1827), an Italian physicist,
disagreed with Galvani's
explanation. In 1796 Volta constructed a pile of a large number of alternate
silver and zinc disks and placed a piece of cloth,
moistened with a salty solution, between every other disk.
The first battery was invented: the Volta pile.
However, this battery was not very practical and had very little power.
soon improved his invention by devising his "Crown of Cups", a number
of cups filled with sulphuric acid into which metal strips were dipped. Half
of these strips were copper and the other half zinc.
between static electricity and electro-dynamic electricity was now fully understood.
Assuming that the tiny figures are electrons, one can better understand the
difference between a static electric charge and an electric current. In a
static charge all the electrons are on the surface and at rest, except here
and there an occasional electron that escapes. In the case of an electric
current the electrons rush along the inside of the conductor.
now followed in rapid succession:
Marie Ampčre (1775-1836), a French physicist,
discovered the solenoid: a spiral coil of wire that
behaves like a magnet when an electric current flows through it.
Sturgeon (1783-1850), an English army physicist, invented the first
electro-magnet by winding bare copper wire, insulated by silk thread, around
a soft iron bar. When a current flows through the copper wire the iron becomes
a magnet. When the current ceases the iron is no longer a magnet. 1827
Simon Ohm (1789-1854), a German physicist, formulated his famous law
connecting voltage, current and resistance in an electric circuit (V=I.R).
Joseph Henry (1797-1878),
professor of Princeton N.J., created an electro-magnet of much greater strength
and efficiency by winding the ironcore with several more layers of wire and bending its shape:
the horse-shoe magnet.
Michael Faraday (1791-1867), professor of physics, devised a machine to convert mechanical energy into electricity. A copper disk
was mounted between the poles of a big horse-shoe magnet and the rim and axle
of the disk were connected to a galvanometer. When the disk rotates the galvanometer
needle moves. The dynamo was invented, for the first time a steady currentof electricity could be produced without the use of a battery. 1836
Frederic Daniell (1790-1845), an English chemist, invented the first
reliable galvanic element: the Daniell battery.
reliable sources of energy are available electricity can be applied to horology.