PLATE 24 



Tracks of Chief Vessels on Which Magnetic Observations Were Made in the Pacific Ocean, 1839-1916. 



Galilee. 1905-1908 



Carnegie, 1911-1916 ' 



Cluett, 1914 (Atlantic) • • • 

 Challenger, 1872-1876 



Erebus and Terror, 1839-1843 Carnegie, 1916-I9I7 (projected) 



Gazelle, 1874-1876 * — * — <■ * Novara, 1857-1860 - Coast a'nd Geodetic Survey, 1903-1915 



Discovery, 1902-1904 



