Born in the Somme department of France, Peltier was a watchmaker who gave up his profession at the age of 30 to devote himself to experimental physics. In 1821 T. J. Seebeck had shown that if heat is applied to the junction of a loop of two different conductors a current will be generated. In 1834 Peltier demonstrated the converse effect (the Peltier effect). He found that when a current is passed through a circuit of two different conductors a thermal effect will be found at the junctions. There is a rise or fall in temperature at the junction depending on the direction of current flow.