[32] From “Library of Southern Literature”, VIII, 3440.
PILOT CHART OF THE NORTH ATLANTIC
(Chart from inside front cover)
PILOT CHART
OF THE
NORTH ATLANTIC
M. F. Maury. L.L.D. Lieut. U.S. Navy.
National Observatory, Washington
1853.
New Edition corrected 1857.
SHEET NO. 2.
SERIES C.
EXPLANATION.
The object of this chart is to show the relative number of times in every 5° square of the ocean that the wind blows from the several points of the compass for each month. As an example, take the square between 5° & 10° N. and 20° & 25° W. The figures in the N.E. corner of the circumscribed square show that in this square, there have been examined 294 records of the winds in Dec; 212 in Jan; & 161 in Feb; and the numbers 33, 18, 8, in the N.E. quadrant of the inner circle, show that it was calm 33 times in addition to the 294 winds in Dec; 13 times in Jan; and 8 times in Feb.
These are the winter months; and the number of times that the wind has been found to blow from the several points of the compass, in the winter months, is entered in the space between the two outer circles. The radii show the points of the compass; the figures between the radii show the number of times, for each month, the wind has been timed to prevail from such points for as much as eight hours together. Thus, between the two heavily drawn radii opening to the North, the winds from N. by W. to N. by E. are entered as North winds. Between the right hand line of these two and the broken radius to the right of that again, the winds between N. by E. & N.E. by N. are entered as winds from N.N.E. Between this broken radius and the next one on the right are the winds from N.E. and so on, with the sun, around the sixteen points of the compass. All the winds between N. by W. and N. by E. are called North winds; those between E. by N. and E. by S. are entered as from E. & so on.
Referring again to the same square, and to the two heavily drawn radii opening to the North, the numbers 20, 8, 16, between the two outer circles, mean, that 20 of the 294 winds in Dec, 8 of the 217 in Jan, and 16 of the 161 in Feb. were North. In Dec, the winds blew also 36 times from N.N.E; 37, N.E; 51, E.N.E; 60, E; 21, E.S.E; 17, S.E; 10, S.S.E; 6, S; and so on.