DAVIS STRAIT AND LABRADOR SEA 15 



The customary practice of spacing the water bottles on the wire 

 was followed, viz, bottles were placed at shorter intervals, directly 

 proportional to the depth of the most rapid change in the tem- 

 perature and the salinity. The maximum depth of observation for 

 the deeper stations was 3,100 meters, with 11 stations 2,000 meters 

 or more, and 61 stations betAveen 1,200 and 2,000 meters. 



The thermometers on board the General Greene for the 1931 expe- 

 dition totaled 25 as follows: 2 Richter & Wiese and 4 Negretti 

 & Zambra with scales graduated into two-tenths of a degree centi- 

 grade. The remainder were of an older type divided into two-tenths 

 of a degree and without auxiliary thermometers. 



The Greene-Bigelow water bottles contained two thermometers 

 each, old and new thermometers being paired together, the correc- 

 tions for the instruments having auxiliaries being applied also to 

 those without same. A comparison of all corrected temperatures 

 showed a difference less than one one-hundredth of a degree centi- 

 grade in 34 percent of the observations. The average difference for 

 all the temperature records was 0.03° C. The mean corrected tem- 

 peratures of paired thermometers is shown in the 1931 station tables 

 except where a difference greater than 0.04° C. occurred. In such 

 cases only the corrected temperature from the thermometer equipped 

 with the auxiliary has been printed. 



The surface temperatures were obtained with thermometers having 

 a scale divided into 0.1 of a degree centigrade, the length of 1 degree 

 being 10 millimeters. The surface water was brought on deck by 

 means of a metal dip bucket. 



Salinities in 1931 were determined partly by means of the electric 

 conductivity method on board or by means of titration. Faulty 

 mechanical functioning of the electrical equipment necessitated re- 

 course to titration of about 100 samples from stations 1220 to 1287 

 on board and titration of samples from stations 1288 to 1341 at 

 the Woods Hole Oceanographic Institution on the return of the 

 General Greene. Each sample was titrated twice, and if the differ- 

 ence in salinity exceeded 0.02%o a third titration was made. Out 

 of approximately 550 samples, stations 1220 to 1286, along the Labra- 

 dor coast, 250 have been determined twice. At those stations where 

 titrations have been made, the mean of the determinations by the 

 salinometer and by titration, have been printed in the tables except 

 where the difference exceeded 0.03%o, and in such cases titrated 

 values only have been used. 



There are about 300 salinities, stations 1220 to 1287, which have 

 been determined by the salinometer only once, and it is, of course, 

 impossible to tell the accuracy of these determinations. Salinity 

 curves for each station, however, have been carefully constructed, 

 and they do not show any marked irregularities in the deeper or 

 higher strata, the salinities apparently agreeing very well with the 

 checked values. The values of the salinities from stations 1254 and 

 1255 are higher by 0.10%o to 0.15%o than for stations 1253 and 

 1256. No extra samples unfortunately were retained from these sta- 

 tions. The salinities are obviously incorrect, and they have, accord- 

 ingly, been stricken from the tables. 



As in 1928 on the Marion the General Greene carried no unpro- 

 tected thermometers in 1931. It was attempted, as far as possible, 



