INTRODUCTION 



N450 4-|-m. tow-net. Mouth circular, 4^ m. (14-8 ft.) diameter: mesh graded, at cod-end of 

 7 mm. (0-28 in.) netting lined for part of its length with 4 mm. (o-i6 in.) netting. 



NS 50 Experimental high speed tow-net, primarily for krill. Rigid construction of fore and 

 mid sections, which are covered with i in. (2-5 cm.) mesh wire netting; after part of 

 cotton netting, with bucket. Mid section has 7 mm. (0-28 in.) netting stitched inside 

 wire; after section of 4 mm. (o-i6 in.) netting backed with stramin. Width at mouth 

 30-5 cm. (12 in.) widening to 50 cm. (19-5 in.) at ^ of rigid length and narrowing to 

 15-25 cm. (6 in.) at end of frame. Length of after part 61 cm. (24 in.) and overall length 

 198 cm. (6-5 ft.). Towed direct from point on fore end ring and balanced by 28 lb. 

 (127 kg.) lead weight secured to frame forward, on opposite side to towing point. 



OTL Otter trawl. Head rope 40 ft. (12-2 m.) long: mesh at cod-end i J in. (3-2 cm.). 



Sh. Coll. Shore collecting. 



TD Transparency (or Secchi) disk, 50 cm. (19-5 in.) diameter. 



TYF Young-fish trawl. A bag of stramin, with 10-12 meshes to the linear inch, attached to 



a circular frame 2 m. (6-6 ft.) in diameter. 



V Vertical. 



To the symbols for tow-nets (N 450, N 100, N 70, N 50 and TYF) B, H or V is 

 always added to indicate whether the haul was made obliquely, horizontally or verti- 

 cally. For determining the depths of horizontal and oblique nets, Kelvin sounding 

 tubes or depth gauges were employed. Their use is indicated by the appropriate 

 symbols in the ' Remarks ' column ; where the tube or gauge failed to register the depth 

 was estimated and is noted as such. Details of fishing large plankton nets are given by 

 Marr (1938). The experimental high speed tow-net (NS 50), when used, was towed 

 immediately prior to a full station. The times of shooting and hauling are thus before 

 the time given for the beginning of the Stations, but the inclusion of this net in the 

 station observations enabled the sample to be given the number of the station con- 

 cerned. 



The state of the sea is expressed as a number in the Douglas Sea Scale, which is as 

 follows : 



STATE OF SEA 



The following symbols are used to denote the meteorological observations on the 

 state of the weather : 



b blue sky whether with clear or hazy atmosphere, or sky not more than one-quarter clouded. 



be sky between one-quarter and three-quarters clouded. 



c mainly cloudy (not less than three-quarters covered). 



d drizzle or fine rain. 



e wet air without rain falling. 



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