ATLANT. DEEP-SEA EXPED. 1910. VOL. i] PHYSICAL OCEANOGRAPHY AND METEOROLOGY 



15 



effect will be even more marked than in the case of 

 constant flow of "Equatorial" air, because this would 

 have been subject to continual cooling and therefore be 

 in a state of stability. In the latter case, however, an 

 encounter with "Polar" air would give a vertical com- 

 ponent upwards, with a resulting condensation and rainfall. 



In view of what has been said above it seems very 

 desirable to establish closer and more general co-operation 

 between physical oceanography and meteorology than 

 has hitherto existed.') 



III. SUB-SURFACE TEMPERATURES, SALINITIES, 

 and DENSITIES (METHODS). 



12. The Temperature Observations. 



In by far the greater number of cases the sub-surface 

 temperatures were observed by means of reversing ther- 

 mometers obtained from C. Richter in Berliti. The ther- 

 mometers were carefully tested, and new determinations 

 of the zero-point were made on April 9th. Almost without 

 exception the best thermometers worked excellently. In 

 one of the water-bottles the same two thermometers 

 where used simultaneously 517 times. The difference 

 between the corrected temperatures was 



The average difference was less than 001° and the 

 mean error about + 0-005° C. 



The determinations with each thermometer are slated 

 separately in Table II. The thermometers were always 

 allowed 3 minutes or more at the depths of observation 

 before they were reversed. The thermometers were read 

 by means of a magnifying lens [cf. Hell.'^nd-Hansen, 1912, 

 for further particulars as to the reading and correction of 

 the thermometers]. 



Pettersson-Nansen's insulating water-bottle was used 

 at some stations, viz: 



Stat. 



10, 183 metres (the first observation, at 14'' 41'") 

 274 m, 640 m. (the second observation, at 

 15'' 50""), 914 m. (the first observation, at 

 14" ll-"), and 1372 m. 



10 A, 1829 metres. 



91, 4750 „ 



97 — 116 (incl.), for all sub-surface obser- 



In these cases a NANSEN-thermometer, fixed tightly 

 in the lid of the water-bottle, was used for the temperature- 

 determinations, generally together with a reversing ther- 

 mometer placed in a special frame on the water-bottle. 

 The readings of the NANSEN-thermometers were corrected 

 for the adiabatic cooling of the water-sample and the 

 water-bottle as well as for instrumental error. The cor- 

 rected temperatures recorded by the NANSEN-thermometer 

 are marked with an asterisk in Table II, in the case of Stations 

 97 — 116. In the case of the other stations mentioned 

 above, the asterisk was inadvertently omitted when prin- 

 ting the Tables. Where a determination with a reversing 

 thermometer was also made, the temperature is printed 

 in the Tables below that recorded by the NANSEN-ther- 

 mometer. 



The same NANSEN-thermometer (made by Muller in 

 Ilmenau) was always used in the Pettersson-Nansen 

 water-bottle. By determinations of the zero-point on April 

 9th the reading in pure melting ice was —0027° C, 

 and the relative corrections for other parts of the scale 

 were known from earlier determinations. When the ther- 

 mometer was used at Stat. 10 it was observed that a 

 small drop of mercury had detached itself and come 

 into the upper enlargement of the thermometer. It could 

 not be brought back again by simple means available on 

 board. When the thermometer was used afterwards, it 

 was observed that the small drop apparently remained 

 constant. After the return of the Expedition to Bergen 

 it was found that the reading of the thermometer in pure 

 melting ice was —0-09° C, the drop thus corresponding 

 to 006°. 



vations. 



') During the "Armauer Hansen" Expedition to tlie eastern part 

 of tlie Nortli Atlantic in tlie summer of 1922 very extensive mete- 

 orological material was collecleJ in close connection with liydrogra- 

 pliical observations. This work was to a great extent inspired by 

 the results of the 'Michael Sars" Expedition. 



