9306 on 11 and 12 April 1965, and referred to 

 herein as tlie check survey to detect any changes 

 in the horizontal and vertical distribution of 

 water mass types and associated dynamic prop- 

 erties. The first cruise was terminated on 12 April 

 1965. 

 During the second cruise, which lasted from 



24 April to 12 May 1965, Evergreen occupied serial 

 stations 9313 to 9351 to pi'ovide a dynamic topo- 

 graphic chart of the water over the northeastern 

 slope of the Grand Banks. These stations, which 

 were occupied duruig the period 7 May to 10 May 

 1965, were in eastward oriented sections termi- 

 nating at the latitude of Flemisli Cap and rep- 

 resent an attempt to define any easterly branch- 

 ing of the Labrador Current. 



The thu'd cruise began with the occupation of 

 station 9352 on 19 May 1965. A line of serial 

 stations running east to the northern tip of Flemish 

 Cap was occupied to provide overlap with the 

 sections completed on the previous cruise. Serial 

 stations weve occupied d(jwn to the Tail-of-the- 

 Banks which approximated those occupied during 

 the first cruise. Occupation of station 9408 on 



25 May 1965, completed the survey for the season. 



Additional Projects 



As a part of a continuing study of iceberg drift 

 and deterioration, a series of photographs, sup- 

 ported by sextant angles and range finder dis- 

 tances, were taken at 30-degree intervals around a 

 berg to permit detection of mass wastage. These 

 observations were made at approximately 24-hour 

 intervals during the period from 26 April to 6 May 

 1965. A track of the drift of the same berg was 

 maintained by hourly navigational positions ob- 

 tamed by radar reference to a buoy from 26 to 29 

 April 1965. Experimental dye-marking of the 

 berg selected for these studies was also performed. 



A study of the effect of pH of seawater upon 

 its electrical conductivity, as utilized in salinity 

 measurements witii the inductive salinometer, was 

 conducted during the first cruise as was a study 

 of the possibility of classification of surface water 

 type by Forel Color Scale. Inconclusive results 

 were obtained and no data is presented. 



During the first cruise an investigation was 

 made of the steady state conditions presumptive 

 in geostrophic circulation by means of analysis of 

 electronic bathythermograph (ELBT) traces. 

 The traces obtained gave indications of gross 

 changes in the thermal structure over all periods 

 covered by the study (6-minute to 1-week scales). 



Instrumentation 



Teflon-lined water sampling bottles of the 

 Nansen type, manufactured by the Ballauf Manu- 

 facturing Co. or the United Machine Co., were 

 used during each cruise. Temperatures were 

 measured with protected deep-sea reversing ther- 

 mometers mostly of Richter & Wiese manufacture, 

 but with some manufactured by G. M. Manufac- 

 turing Co., Kahl Scientific Instrument Corp., and 

 Walter H. Kessler Co., Inc. Thermometer per- 

 formance was continually monitored by pairing 

 and intercomparison. The following standard de- 

 viations from the accepted paired average reflect 

 thermometer performance during the season. 



Depths of observation are based on wire angle 

 geometry and thermometric computations from 

 unprotected deep-sea reversing thermometers. 

 The salinity of each seawater sample collected 

 was measured with an RS-7A inductive salinom- 

 eter manufactured by Industrial Instruments 

 Corp.. Forty-one replicate salinity samples were 

 intercompared using a Hytech Corp. 6210 in- 

 ductive salinometer which yielded a standard 

 deviation of 0.007°/«.. The salinity determination 

 procedures used were those described by Morse 

 (1963). It is considered that the precision of 

 measurement was within 0.005 /= and that the 

 accuracy of the reported salinities is ±0.01 / = . 



Depth to the bottom at each station was de- 

 termined with an Alpine Precision Echo Sounder 

 Recorder (PESR). 



All observed data were processed by a PDP-5 

 digital computer manufactured by the Digital 

 Equipment Corp. The computer was programed 

 for the correction of reversing thermometers and 

 determination of thermometric depth; computa- 

 tion of sigma-t, specific volume anomaly and 

 dynamic height integration; and computation of 

 volume transport. The programing of the com- 

 puter lias been described in greater detail by 

 O'Hagan (1964), and Morse and O'Hagan (1964). 



At eacli station a Hylech Corp. electronic 

 bathytiiermograph (ELBT) Model 480 MOD I, 



