John Frederic Daniell (1790-1845) was born
in London and took his first job at a sugar refinery and resin factory.
After hearing William T. Brande’s lectures on chemistry, he
was inspired to start his own research. In 1831, he was appointed
professor of chemistry at King’s College, London.
Daniells’s research into development of constant
current cells took place at the same time (late 1830s) that commercial
telegraph systems began to appear. Early telegraph messages were
brief and traveled short distances. Crude, weak batteries were sufficient
to support the signal. With the increase in traffic and introduction
of Morse sets, stronger currents and more constant output were required
in the batteries. Daniell’s copper-depolarized battery (1836)
and Grove’s nitric acid depolarized cell were fortuitous arrivals.
British and American telegraph systems used the Daniell cell exclusively,
as it was the only one capable of being rapidly depolarized. His
cells also produced a more constant output and generated a stronger
current than Sand batteries. This was the “pre-volt”
period, when the intensity of pain was used as a measure of a cell’s
In 1839, Daniell experimented on the fusion of
metals with a 70-cell battery. He produced an electric are so rich
in ultraviolet rays that it resulted in an instant, artificial sunburn.
These experiments caused serious injury to Daniell’s eyes
as well as the eyes of spectators. Ultimately, Daniell showed that
the ion of the metal, rather than its oxide, carries an electric
charge when a metal-salt solution is electrolyzed.
Daniell was a friend and
admirer of Michael Faraday and in 1839 he dedicated his book “Introduction
to the Study of Chemical Philosophy” to him.