Complex sentence: He was the Conservative MP for Dumfriesshire, elected at the 1865 general election but losing to Liberal Sydney Waterlow at the 1868 general election, but regained his seat at a by-election in 1869 owing to the disqualification of Waterlow by becoming a government contractor.
Split into simpler sentences: He was the Conservative MP for Dumfriesshire, elected at the 1865 general election. He lost to Liberal Sydney Waterlow at the 1868 general election, but regained his seat at a by-election in 1869 owing to the disqualification of Waterlow when he became a government contractor.