INTRODUCTION 129 



considerations. In general they were from 10-25 sea-miles apart. At full stations complete series of 

 water-samples with temperature determinations at standard depths throughout the water-column 

 were obtained ; simultaneously standard series of vertical-closing plankton nets were fished down to 

 1000 m., or as deep as soundings permitted, and a vertical haul with the fine-meshed phytoplankton 

 net was made. Towed plankton nets were not fished during the first survey owing to lack of time. 

 Full details are given in the Station list (see references). 



At the intermediate stations the ship was hove-to for a vertical haul with the phytoplankton net, 

 which enabled us to make temperature observations with the bathythermograph loaned by the 

 U.S. Navy, down to the limit of the depth range of the instrument (138 m.). Three hauls with a 

 commercial otter-trawl (WS 974, 990, 999) were made on the continental shelf, providing some 

 indication of the nature of the demersal fish-fauna and material for speciation studies in the genus 

 Merluccius (hake) by Mr N. B. Marshall of the British Museum (Natural History). 



Seventeen full stations and twenty-two intermediate stations were worked, over the area of some 

 60,000 square miles, in nine days. We could not spend more time in order to make the coverage more 

 complete, since this could only have been done at the expense of the rest of the ship's programme. 

 Details of the itinerary are given below (pp. 141-144). 



The second survey (Fig. 2) was essentially a repetition of the first, at the opposite season of the year, 

 but with more time available it became possible to increase the collections at the reoccupied stations, 

 and to make some additional observations. Oblique and horizontal towed plankton-nets were fished 

 at all full stations in addition to the vertical series, and horizontal towed nets at intermediate stations. 

 Bottom samples were collected at nearly all the stations on the shelf, and a few additional stations 

 were occupied for this purpose alone, to gain further knowledge of the distribution of thediatomaceous 

 'azoic' mud. The ship also worked in collaboration with Commander W. J. Copenhagen for a brief 

 period while in the Walvis Bay area, assisting in researches he has described in another report 

 (Copenhagen, 1953). Additional intermediate stations were worked both north and south of the area 

 previously covered, and alternate stations on the most northerly, east-west line were made into full 

 stations. Thus the number of full stations was increased to twenty and of intermediate stations to 

 forty-four (thirteen being bottom-sampling stations only). 



Full details of meteorological, physical and chemical data collected, and biological collecting gear 

 used at each station on both surveys, are given in the Station List, already published in the Discovery 

 Reports (1953). Methods are described and discussed in a later section of this report. 



The ship was commanded by Lieut. -Cmdr A. F. Macfie, O.B.E., R.D., R.N.R., whose experience 

 and ready assistance with the work at sea, and advice to the scientists when practical considerations 

 rendered modifications of programme unavoidable, were prime factors in the successful completion 

 of both surveys. Mr R. Baty, the chief Engineer, and his department gave unstinted help in servicing 

 scientific gear, despite unlooked for difficulties with other auxiliary machinery. Mr K. Maclean, the 

 chief officer, who organized the assistance needed from the watch on deck during station work, also 

 obtained valuable recorder runs with the echo-sounding machine, and with the bo'sun, Mr Yorke, 

 devoted much care to its maintenance. Mr M. R. B. Hawkins, the navigator, also recorded meteoro- 

 logical data, and Mr W. Slater, third officer and trawling expert, also helped in many ways outside 

 his routine duties. Such projects must always depend upon the able co-operation of the whole ship's 

 company, so that the data recorded and the biological collections made are a reflection of the way all 

 hands turned to at an arduous, unfamiliar assignment. 



The scientific personnel were Dr T. J. Hart, Dr (then Mr) Robert Clarke and Mr R. 1. Currie. 

 Dr Hart was in charge of the work at sea during the first survey, handing over to Dr Clarke at the Cape 



