Each district elected two senators (plurality-at-large): The first-placer was to serve a six-year term while the second-placer was to serve a three-year term. On each election thereafter, one seat per district was up (first past the post). The senators from the 12th district were appointed by the American governor-general for no fixed term.
Each district elected two senators (majority-at-large): The top candidate received a six-year term, while the second-place finisher secured a three-year term. In subsequent elections, one seat per district was contested (first past the post). The 12th district's senators were appointed by the American governor-general without a fixed duration.