Kahl Scientific Instrument Corp. Depths of observation are based 

 on unprotected reversing thermometers made by Richter & Wiese and 

 hy Kahl Scientific Instrument Corp. As in other years, a program of 

 intercomparison of protected thermometers was carried out in the 

 field measurements. The thermometers were used in pairs and one of 

 each pair was shifted periodically so that the same thermometer was 

 eventually paired with a number of otlier thermometers. From a 

 total of 2,022 intercomparisons, the standard deviation between the 

 corrected readings of a pair of protected thermometers was ±0.010° C. 

 Of these comparisons, 1,611 involved thermometers having a range of 

 — 2° to +8° with a standard deviation of ±0.008°, 310 comparisons 

 between thermometers of range —2° to +20° or greater gave a 

 standard deviation of ±.013° and 101 comparisons were between 

 thermometers with a range of +3° to +13° and gave a standard 

 deviation of ±0.008°. As most of the observed temperatures listed 

 in the Table of Oceanograpliic Data are the means of the corrected 

 readings of a pair of thermometers and as numy of the tliermometers 

 had recent ice point determinations, it is considered that tlie tabulated 

 observed temperatures are good to ±0.01° C. 



As in past j^ears, salinities were measured with a Wcnner sahnity 

 bridge. Prior to the beginning of field work, two check rims were made 

 to verify the calibration curve using samples whicli had been stored 

 in glass for 1 3'ear after the precise chlorinity determinations nuule in 

 February of 1960. No significant change in the calibration curve 

 was observed. In the field measurements, the bridge was standardized 

 with water from an oil-sealed carboy of sea water. Copenhagen 

 standard water of batch P29 was measured as an unknown twice during 

 each sahnity run. At the end of each survey, these measurements 

 were used to correct the tentative value of tlie sahnity of the oil-sealed 

 carboy which liad been used as a substandard of salinity and to deter- 

 mine the corrections to the salinities for the survey. The corrections 

 indicated were as follows: first survey +0.01n°/oo; second survey 

 + 0.005%o; third survey +0.0l2°/oo; fourth survey +0.00i°/oo; post- 

 season survey +0.02o°/oo. Necessary corrections have been applied to 

 the tabulated values appearing ui the Table of Oceanograpliic Data and 

 have been considered in the construction of the dynamic topographic 

 charts. Temperaturecontrolof the samples in the electrolytic cells of the 

 bridge limit the precision of the individual measurements to 0.005°/oo. 

 In view of the precise chlorinity determinations of February 1960 

 and the check runs on the calibration curve this would also have been 

 the accuracy of the 1961 field measurements. Difficulties with the 

 standardization technique, however, make it appear tliat the precision 

 and accuracy of the values tabulated here are about 0.01 °/oo. 



Figures 15 through IS show the dynannc topography, in chronolog- 

 ical order, found during the four surveys made during the season. As 

 in the past, the reference surface used was 1000 decibars. The first 



21 



