4 DREDGING AND HYDROGRAPHIC RECORDS OF 



All positions so far as possible are located by the true bearing 

 from the ship of the nearest important or prominent shore feature; 

 for stations too far from land to locate in this manner, only the 

 astronomical position in degrees and minutes of latitude and longi- 

 tude is given. To obviate, in locating positions, inaccuracies that 

 may arise from the incorrectness of charts, the number and edition 

 of the chart used is given in a separate column. In the case of 

 stations H. 4828 to H. 4831, where the chart used is obviously 

 inaccurate, the navigator's angles also are recorded. 



"Time of day", as assigned in that column to each operation, is, in 

 the case of a sounding, the time when the plummet struck bottom; 

 in the case of the haul of a net or piece of collecting apparatus, it is 

 the time when such apparatus was in place and the actual towing 

 or dragging commenced, except in case of the pump-filter, as else- 

 where explained. With surface nets, this is the time when they were 

 in the water and began to be towed or the current to pass through 

 them; with intermediate or bottom apparatus, when it had reached 

 bottom, or the level at which it was to be towed or from which it was 

 to be hoisted vertically. In reaching such position the apparatus 

 is assumed to have sunk vertically without making any catch. The 

 "time" of a temperature observation is the time when the ther- 

 mometer was capsized. 



"Depth" (in fathoms) is the depth obtained by the sounding when 

 a sounding was made. In cases where no sounding was made the 

 depth is estimated from the chart. The least and greatest depths 

 are given when the operation was of long continuance. 



Under "Temperatures" the minimum and maximum for the 

 whole period occupied at the station are given. Where a single 

 temperature is given it indicates that no change occurred during 

 the occupation of the station. 



In the double column "Trial " is indicated the depth at which appa- 

 ratus was worked, as well as the duration of operation. In the case of 

 surface nets, this latter is the time towed ; for intermediate nets, 

 the time towed at the depth shown in the depth column is indicated 

 by the first quantity, the time occupied in hoisting by the second. 

 The duration for beam trawls is the time during which the trawl 

 was supposed to be dragging on the bottom, up to the beginning of 

 reeling in. 



In the double column of "Drift" is shown approximately the gen- 

 eral direction in which the gear was hauled as well as the distance. 

 The state of the currents and of the wind, with the exigencies inci- 

 dent to the steering of the ship, make this more or less inaccurate. 



Surface nets were always towed from lower boom at a distance of 

 about 24 feet from the ship's side, unless otherwise specified. 



a See footnote on p. 11 for exception in records of California cruise. 



