They must have got the height of Mt. Rainier from this guy's calculations. I have no idea how people make any map correct without having an aerial view. I'm surprised any maps made before flight are so accurate.
the bottom of the article.
THE EVER-CHANGING ELEVATION
Year, Elevation, Credit, Method
1841 12,333 Lt. Charles Wilkes Triangulation
1879 14,444 James Smyth Lawson Barometer
1888 14,524 E.S. Ingraham Barometer
1896 14,519 USGS Barometer
1897 14,528 Edgar McClure Barometer
1902 14,363 USGS Barometer
1905 14,394 Alexander McAdie Barometer
1914 14,408 USGS Triangulation
1956 14,410 USGS Triangulation
1989 14,411.1 LSAW GPS
1999 14,411.05 LSAW GPS
SOURCES: National Park Service and Land Surveyors of Washington