INTRODUCTION 

 can be made of the probable errors involved, they and the computed at values are included in the 

 list, but they are printed in italics to distinguish them from those which are known to be reliable. 



Phosphates have been determined as previously by the Atkins-Deniges molybdenum-blue method 

 (Harvey, 1948), but the colour comparisons were made in a selenium cell photometer. Silicates were 

 determined by the method of Armstrong (1951). Nutrient salt concentrations are expressed in 

 milligramme atoms per cubic metre. 



Depths measured by unprotected reversing thermometers are recorded in the column headed 

 'Depth by thermometer': those depths recorded in the column headed 'Depth (metres)' were deter- 

 mined from the amount of wire paid out and from the most probable slope of the wire found by 

 interpolation between the thermometric depth measurements. The small index figure placed above the 

 figure for depth shows from which hoist of reversing water sample bottles the sample was obtained. 



The following Beaufort notation has been used to express the state of the weather: 



b blue sky 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 clouded), 



d drizzle or fine rain. 



u ugly, threatening sky. 



Capital letters are used to indicate occasions when the phenomenon noted is intense. On occasions 

 where the intensity is slight the small suffix ' o ' is added. Continuity of the phenomenon is indicated 

 by repetition of the symbol. 



The state of sea and swell is expressed by the appropriate number in the Douglas Sea and Swell 

 Scale, which is as follows: 



Sea Swell 



Calm o No swell 



1 Smooth 1 Low swell, short or average length 



2 Slight 2 Low swell, long 



3 Moderate 3 Moderate swell, short 



4 Rough 4 Moderate swell, average length 



5 Very Rough 5 Moderate swell, long 



6 High 6 Heavy swell, short 



7 Very high 7 Heavy swell, average length 



8 Precipitous 8 Heavy swell, long 



9 Confused 9 Confused swell 



The times of the observations are given in ship's time expressed on the 24-hour system ending 

 with midnight (0000). The hours to be added to or subtracted from ship's (or zone) time to give 

 G.M.T. are noted in the ' Remarks ' column, this difference holding good until another entry is 

 made. Times in heavy type refer to biological observations made between sunset and sunrise. 



301 



