The Welshman William Robert Grove invented the Grove cell in 1839. It consists of a zinc anode dipped in sulfuric acid and a platinum cathode dipped in nitric acid, separated by porous earthenware. The Grove cell provides a high current and nearly twice the voltage of the Daniell cell, which made it the favoured cell of the American telegraph networks for a time. However, it gives off poisonous nitric oxide fumes when operated. The voltage also drops sharply as the charge diminishes, which became a liability as telegraph networks grew more complex. Platinum was and still is very expensive.