GENERAL 
In most instances, the fields of the coding form and punch card 
labeled Bearing, Nautical Miles Drifted, Days Adrift, and Speed may, 
at the option of the originator, be left blank. If values for these 
fields are not reported, they will be computed at the NODC. However, 
when the straight line between release point and recovery point passes 
over land, the originator must determine and code Bearing, Nautical 
Miles Drifted, Days Adrift, and Speed (Columns 63-75). The definitions 
of these terms, as related to the system, are as follows: 
Bearing - The direction of a straight line drawn (on Mercator 
projection) from the release position to the recovery position, expressed 
as an angular distance from 000° clockwise through 360°. 
Nautical Miles Drifted - The straight line distance, in nautical 
miles, between the release and recovery positions. (This distance may 
or may not represent the actual distance traveled by the bottle; it 
does, however, provide a "distance" value for the computation of speed.) 
Days Adrift - The time elapsed (usually in whole days) between 
the time of release and the time of recovery of a bottle. (This time 
entry may or may not represent the actual travel time between release 
and recovery positions; it does, however, provide a time value for the 
computation of speed.) . 
Speed - The value obtained by dividing the entry for "Nautical 
Miles Drifted" by the entry for "Days Adrift." The speed thus computed 
may or may not be related to the actual speed of the bottle. 
