James Prescott Joule

(1818 - 1889)
He was a very important physicist in his time. He´s famous by his investigation in electricity and thermodynamic.
Joule studied the nature of the heat and he discovered his connection with the mechanical work. This led him at the theory of energy´s conservation. It was the first law of thermodynamic. In his honour, the international unit of energy was call joule.
James discovered the connection of the electric current of the resistance with the evaporated heat, called Joule´s Law.
He cooperated with Thomson in the investigation of the cooling of gas.They discovered the Joule-Thomson´s Efect.