The Senate was the upper house of the Parliament of South Africa between 1910 and its abolition from 1 January 1981, and between 1994 and 1997. Under white minority rule in the Union of South Africa, most of the Senators were chosen by an electoral college consisting of members of each of the four provincial councils and Members of the House of Assembly (the lower house of Parliament, directly elected). The remaining Senators were appointed by the Governor-General of the Union on the advice of the Prime Minister. The Senate's presiding officer was called the President, whereas his counterpart in the House of Assembly was the Speaker. The South Africa Act 1909, which created the Senate, included special provisions for the selection of the first elected senators. The Union Parliament was prohibited from changing the arrangements for the Senate during its first ten years. The First Senate included eight senators from each province. They were elected for a ten-year term, by the members serving during the final session of the legislatures of each of the four colonies which joined the Union of South Africa. The election was by a form of the single transferable vote. The remaining eight seats were filled, by appointment (also for ten-year terms) by the Governor-General-in-Council (in effect by General Louis Botha's first Union government). Section 24 of the South Africa Act 1909 provided that, of the nominated Senators, One-half of their number shall be selected on the ground mainly of their thorough acquaintance, by reason of their official experience or otherwise, with the reasonable wants and wishes of the coloured races in South Africa. Casual vacancies in the representation of the provinces, in the First Senate only, were filled by an electoral college composed of the members of the relevant Provincial Council. New senators, elected in this way, held the seat for the residue of the ten-year term. Nominated senators, appointed to fill vacancies, received a ten-year term and did not have to vacate their seats at the end of the term for the provincial representatives.