The Daniell cell (var. sp. Daniel cell), also called the gravity cell or crowfoot cell was invented in 1836 by John Frederic Daniell, who was a British chemist and meteorologist. The Daniell cell was a great improvement over the voltaic pile used in the early days of battery development. The Daniell cell's theoretical voltage is 1.1 volts and the chemical reaction is Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(s).