DKEDGING AND HYDROGRAPHIC RECORDS. 5 



Only those stations where the ship's gear was used (i. e., with the 

 ship as an instrument) to collect natural-history specimens have been 

 designated in the records as dredging stations. At times specimens 

 were taken with dip nets during the occupation of a hydrographic 

 station, but on account of the irregularity of such collecting the station 

 was not regarded as a collecting station. No numbers have been 

 given to the numerous shore stations, nor to minor collections made 

 with the ship at anchor. But numbers have been given in the 

 dredging series to hauls of the large intermediate net when used in a 

 tideway with the ship at anchor. 



Since the shore w T ork constitutes such an important part of the total, 

 the data regarding shore stations is shown in chronological order with 

 the dredging stations, the locality, apparatus, etc., appearing in the 

 appropriate columns. To economize time most of the reef collections 

 of fishes were made with dynamite. The method was to locate the 

 desirable fishes in the coral growth by means of a view glass (a glass- 

 bottomed box) used from a boat. A small charge of dynamite with 

 electrical connections was carefully lowered and discharged. Such 

 fishes as floated were at once collected with a dip net, and the place 

 marked by a buoy. As soon as the bottom had cleared it was searched 

 and the dead fish gathered by diving or more usually by means of 

 long-handled spears. 



The various kinds of apparatus used at each station are recorded 

 in the tables in chronological order, each on a separate line, opposite 

 the station number, or, in case of unnumbered stations, opposite the 

 locality, in the column "Apparatus." 



The "Position" of a station is that point occupied by the vessel, 

 as determined by the navigator at the time of beginning the first 

 operation at that station. The position of the subsequent opera- 

 tions under the same station number corresponds in a general way 

 to the line as indicated under "Drift." The distance covered by 

 all the operations of a station is usually, however, not greater than 

 the negligible error of observation, except in stations near shore 

 determined by bearings. 



In relation to the hydrographic information obtained, the degree 

 of accuracy with which positions are located is of greater importance, 

 and a description of the methods is necessary to the proper use 

 of this information. A great part of the region traversed is still 

 unsurveyed; and even where surveyed, parts are incorrectly or 

 incompletely charted. Owing to press of work and lack of time, 

 no opportunity was afforded to correct such errors, and the best 

 available charts were therefore used as the basis of all determina- 

 tions of position when in sight of land; in the column "Chart" is 

 noted the number and edition of the chart used at each station. 



59395°— 11 11 



