(Text Page to) (18) Earthquakes, magnetism and tides : Lines of equal magnetic variation (isogones) -- Lines of equal annual change in magnetic variation (isopores) -- Semi-diurnal co-tidal and co-range lines west coast -- Semi-diurnal co-tidal and co-range lines east coast. Compiled from information supplied by the Dominion Observatories and Canadian Hydrographic Service. (Canada) Department of Mines and Technical Surveys.

• Main Authors: Canada. Department of Mines and Technical Surveys, Nicholson, N. L. (Norman Leon), Comtois, Paul
• Format: Text
• Language: unknown
• Published: Department of Mines and Technical Surveys, Geographical Branch 1957
• Subjects: Earthquake; Geomagnetism; Newfoundland; North Magnetic Pole; North Pole
• Online Access: https://www.davidrumsey.com/luna/servlet/detail/RUMSEY~8~1~323179~90092274; https://media.davidrumsey.com/MediaManager/srvr?mediafile=/Size4/RUMSEY~8~1/185/14001041.jpg

Descriptive text on verso of (18) Earthquakes, magnetism and tides: Since the North Magnetic Pole is in a different position from the Geographical North Pole, and since the lines of the earth's magnetic forces are deflected by various agencies, the compass needle does not point toward the Geographical North Pole in most locations. The deflection of the compass needle from True North is called magnetic variation or declination . First edition was in 1906 (see our 1645.000); second edition 1915 (1646.000). The title page of this edition is dated 1957 but the Foreword is dated 1958, as well as the maps on plates 91, 99 and 110. Atlas contains 110 plates, comprising a total of 505 maps in color; additionally, these maps include 57 insets. Bound in pale green boards with burgundy lettering and spine, including spine title "Atlas Of Canada. 1957” in gilt. Loose-leaf binding allows both removal and insertion of individual maps. Inside front cover: Canadian made product by Copeland-Chatterson Limited, Brampton, Ontario. In the Foreword, Minister of Mines and Technical Surveys Paul Comtois explains, "Since the last Atlas of Canada appeared in 1915, the economy of Canada has expanded in all directions. The population of the country has doubled. Newfoundland has joined it as the tenth province, and scientific surveys have revealed to an ever increasing extent the physical nature of its land and water resources. It is, therefore, the purpose o this edition of the Atlas to present, in maps, an outline of the physical background and the economic development of the nation at mid-century and to show how these factors are interwoven to produce the fabric of the life of our people … " In the Preface, Director of Department of Mines and Technical Surveys, Geographical Branch, N.L. Nicholson continues, “ … the Atlas provides a logical story in maps which embraces historical, physical, human, economic and social and political geography. The story begins with the way in which Canada was explored and mapped. It goes on to show the ...