Constitution of the Commonwealth of Pennsylvania Schedule 1, § 3. Election of Senators

At the general election in the years one thousand eight hundred and seventy-four and one thousand eight hundred and seventy-five, Senators shall be elected in all districts where there shall be vacancies.  Those elected in the year one thousand eight hundred and seventy-four shall serve for two years, and those elected in the year one thousand eight hundred and seventy-five shall serve for one year.  Senators now elected and those whose terms are unexpired shall represent the districts in which they reside until the end of the terms for which they were elected.