On Mr. Chipping's first day, when he walks up to his desk, the shadow of the boom pole and mic can be seen on the wall beside him.
Miss Kathy tells Chips that the ballroom in Vienna is where Metternich drew up "the treaty of the five kings" (referring to the Congress of Vienna in 1814 ending the Napoleonic Wars) "nearly 100 years ago." But the montage after Kathy's death makes clear she died before the Boer War (1899) and Queen Victoria's funeral (1901). 100 years after the Congress of Vienna was 1914, the start of World War I when Chips becomes acting headmaster, and Kathy is spoken of as having died long ago.