Geologist, historian, writer and politician. Chao was part of the Democratic Party and after the Revolution of 1868, he became a Federal Republican. He was deputy in Orense in 1869, and in 1872, he participated in the assembly of the Federal Republican Party in Madrid, prior to the Spanish general elections in April of that same year. When the First Republic was proclaimed in 1873, he was Minister of Public Works in Nicolás Salmerón’s government. Chao co- wrote, with Salmerón, a Proyecto de bases de la constitución republicana-federal de España.