Gravity and Magnetic Fields — Rose and Belshe 
375 
FIG. 1. Position points along the ship’s tracks of R/V "Charles H. Gilbert” ( circles ) and of R/V "Sur- 
veyor” ( triangles and squares) . 
rection, northeast-southwest tracks were chosen. 
This heading also resulted in the profile tracks 
being perpendicular to the structural strike of 
the Hawaiian Swell. Sea conditions were un- 
usually calm during the entire cruise, allowing 
approximately 1000 miles of gravity observa- 
tions out of approximately 1170 miles of total 
cruise. A note of unusual interest is that for the 
three crossings of the Molokai channel (usually 
characterized by confused high seas) the seas 
were abeam, yet the Browne correction was only 
200 mgal on the last crossing and less than 100 
mgal on the first two crossings. 
The Browne corrections for the long south- 
west-northeast tracks were approximately 300, 
200, and 400-600 mgal for the west, central, 
and eastern tracks, respectively. The central and 
eastern tracks had following seas. The tracks 
close to the islands generally had total Browne 
corrections of approximately 100 mgal. 
Bathymetry was obtained from the "Gil- 
bert’s” fathometer to 250 fm, and from E. L. 
Hamilton’s 1953 and 1954 (unpublished) bot- 
tom contour charts northeast of Oahu, and 
F. P. Shepard’s (unpublished) bottom contour 
charts of Kaneohe Bay and of the north coast 
