Collection search - Iso magnetic maps of Western Canada for 1922. O. (1) Lines of equal magnetic decelination and of equal annual change in Western Canada for 1922.O. (2) Lines of equal magnetic inclination in Western Canada for 1922.0 and of equal annual change between 1917.0 and 1922.0. (3) Lines of equal magnetic horizontal intensity in Western Canada for 1922.0 and of equal annual change between 1717.0 and 1922.0. [cartographic material]

Date modified: