Although the design of a dome car can be likened to a cupola caboose, the dome car's development is not directly related. The earliest documented predecessor of the dome car was first developed in the 1880s; known at the time as the "birdcage car", it was used on an 1882 sightseeing tour on the Chicago, Burlington and Quincy Railroad. In 1891, T. J. McBride received a patent for a car design called an "observation-sleeper"; illustrations of the design in "Scientific American" at the time showed a car with three observation domes. Canadian Pacific Railway used "tourist cars" with raised, glass-sided viewing cupolas on their trains through the Canadian Rocky Mountains in the 1920s.