54 



Der tindes imidlertid blandt vore Stationer nogle, 



hvor Usikkerheden af den paaværende Plads gaar op til 5 

 å 6 Minuter. nemlig udenfor den nordvestlige Del af Spids- 

 bergen. nordenfor 78° Bredde. Effcerat den paaværende 

 Plads var bestemt ved Solobservationer saavel Formiddag 

 som Eftermiddag, viste det sig. da vi tik Land i Sigte, at 

 Resultatet af Pejlinger af Nordpynten af Pr. Charles 

 Foreland gav en 5' til 6' sydligere Plads end Sol- 

 observationerne. Men Aarsagen viste sig ogsaa i en stærk 

 Hildring, der krævede en anden Værdi for Kimmingdalin- 

 gen end den normale, som var benyttet. Under saadanne 

 Forhold er paaværende Plads umulig at bestemme med 

 vanlig Nøjagtighed eiter Solobservationer, selv om man laa 

 for Anker og observerede Højder i alle Azimuther. thi 

 Horizontalrefraktionen vil variere med Retningen og med 

 Dagstiden paa en ganske uperiodisk Maade, der er umulig 

 at bringe i Regning. Et lignende Exempel paa Virkningen 

 af Hildring havde vi om Morgenen den 10de August 1877 

 udenfor Lofoten. Maaling af Horizontalvinkler mellem 

 kjendte Punkter gav Fartøjet en paaværende Plads, der 

 laa i en betydelig Afstand fra den Stedlinie, som en over 

 den ostlige. falske Horizont maalt Solhøjde gav. 



Til Slutning skal jeg nævne. at Expeditionen var ud- 

 rustet med Apparater til at maale Strøm i Overfiaden og 

 paa Dybet, Disse kom ikke til Anvendelse, først fordi 

 Vejret det første Aar var saa særdeles ugunstigt, og senere 

 fordi de andre Arbejder, som skulde udføres, krævede al 

 vor Tid og ikke turde forsinkes af Operationer, om hvilke 

 det altid maatte være tvivlsomt, hvorvidt noget brugbart Resul- 

 tat kunde erholdes. Bestemmelser af Strømmen i Overfladen 

 effcer den almindelige nautiske Methode lod sig ikke. und- 

 tagen i yderst faa Tilfælde. udføre paa vor Expedition. da 

 Sejladseii under Skrabuing, som nævnt, umuliggjorde et 

 skarpt Hestikbold. 



Meanwhile. for some of our observing-stations, the 

 possible error of the shij>'s position amounts to from 5 to 

 li miles. viz. those off the uorth-western extremity of Spitz- 

 bergen. in latitude from 78" to 80° N. After determining 

 the ship's position by observations of the sun's altitude. 

 tåken before as well as after noon. we found, on sighting 

 land. the bearing of the northern promontory of Prince 

 Charles' Foreland to give a point from 5 to (5 miles farther 

 south than tliat determined by the solar altitudes. Tbis. 

 however. was obviously the result of mirage; and hence 

 our constant value for the dip of the horizon would not 

 serve. Under such circumstances it is impossible, were the 

 ship at anchor even and the altitudes observed in all azi- 

 mutbs, to determine her position with the usual accuracy 

 by observations of the sun. since the horizontal refraction 

 according to the direction and the time of da.y will not v a ry 

 periodically, and its true value cannot be tåken into account. 

 A similar instance of the effects of mirage occurred on the 

 morning of the lOth of August 1877, off Lofoten. By 

 measuring horizontal angles betveen known objects, wc 

 found the ship's position to be a considerabh- distance from 

 the line of equal altitudes marked out from observations 

 of the sun above the eastern delusory horizon. 



Finally. I must not omit to mention thnt the Expe- 

 dition was provided with instruments for determining both 

 surface and deep-sea currents. These apparatus, however. 

 were not made use of. - - at first owing to the very unfa- 

 vourable weather we encountered on the opening cruise, and 

 afterwards to avoid impeding the chief exploratory work by 

 operations from which it was auvthing but certain that 

 practical results would be obtained. Nor bad we. save in 

 a very few cases, opportunity of determining the surface- 

 current in the usual nautical way, the effect of dredging aud 

 trawling. as stated above. inevitably putting us out of our 

 reokoning. 



•■ i 



Translated into Enjrlish by John Hazeland. 



