Animated 19th century engraving of Humphry Davy using electrolysis to isolate the metals alkali and alkaline earth compounds. He is shown experimenting at the Royal Institution in 1807. Davy used a combination of Voltaic batteries to give the highest electrical power he could obtain, and ran an electrical current through a solution of potash, which allowed him to isolate potassium metal. This was the first metal to be isolated by electrolysis. He discovered that alkalis and alkaline earths are compounds formed by oxygen combined with metals. Using electrolysis he went on to isolate sodium, strontium, magnesium, calcium and barium. Humphry Davy is on the right. The Voltaic batteries are seen on the table in front of him.