146 DISCOVERY REPORTS 



190 1-3, of which Captam (then Lieut.) R. F. Scott was leader, was purchased and 

 refitted for her new work, and in July 1925, with the consent of His Majesty the King, 

 she was commissioned as the Royal Research Ship 'Discovery'. 



In drawing up a programme for the scientific operations of this vessel the Discovery 

 Committee recognized the immensity of the area in which observations were required 

 and the numerous directions along which research might profitably be undertaken. But 

 practical considerations made it necessary to set some limit to the scope of the work, 

 and in the plan which was finally adopted preference was given to investigations holding 

 the most early promise of useful economic results. 



To examine the conditions existing on the whaling grounds of the Dependencies was 

 evidently of first importance and an intensive survey of the waters in the neighbourhood 

 of South Georgia was planned. In this survey, which it was hoped to repeat annually, 

 observations on the plankton and hydrology were to be taken at close intervals, the 

 former comprising both vertical and horizontal tow-net hauls, worked on a scheme in- 

 tended to give strictly comparable results, the latter designed to supply the fullest 

 possible information on the temperature, salinity, hydrogen-ion concentration and phos- 

 phate and oxygen content of the water. 



Such intensive surveys would not, however, yield all the information desired. Ex- 

 perience in the north had shown that conditions in any localized area can be properly 

 understood only by a study of the mass movements of water in the surrounding oceans ; 

 alterations in the direction and intensity of these movements will involve marked altera- 

 tion in the physical and biological environment of any small area situated in their path. 

 It was thus necessary to supplement the survey of the South Georgia grounds by other 

 investigations — necessarily less intensive — spread over a wider field. The region en- 

 closed by lines connecting the Falkland Islands, South Georgia, the South Orkneys, 

 the South Shetlands and Cape Horn was considered the most important, but observa- 

 tions were to be made whenever practicable in other parts of the southern ocean. 



It is in these investigations that the ' Discovery ' has been primarily engaged during a 

 commission which lasted two years,^ but before she left this country the Committee 

 foresaw that the work was likely to be more than a single square-rigged vessel could 

 undertake and that certain other lines of research were beyond her power. 



Whales are well known to be migratory animals. In the southern winter they are 

 for the niost part absent from the waters of the Dependencies and there is definite 

 evidence that the Humpback travels up the west coast of Africa in the southern autumn 

 and returns to the south in the following spring. There is good reason to believe that 

 this species pairs, and that the young are born, during this sojourn in warmer waters, 

 and the available evidence indicates that little or no food is taken at this time. In the 

 south there are abundant food supplies and the migrations have in consequence been 

 called respectively the breeding migration (northwards, in the southern winter) and the 

 feeding migration (southwards, in the southern spring). Such information as we possess 



1 Some indication of the degree of success which has so far attended the work may be obtained by in- 

 spection of the charts accompanying the Station List, Plates I-V of this volume. 



