20 



Den følgende Dag. den 31te Juli, laa Expeditionen 

 til Ankers i den store Rækved-Bugt paa Jan Mayens Øst- 

 side. Da Søgangen hindrede os fra at komme i Land, toges 

 fra Skibsborde en Række Solhøjder, med forskjellige Sex- 

 tanter, dels af Capt. Wille, dels" af mig. Omstændighederne 

 vare ikke gunstige. Skyer og Taage tog jevnlig Solen eller 

 Horizonten bort. 



Den Ute August varVejret noget gunstigere, og der 

 observeredes om Formiddagen en Del Solhojder fra samme 

 Ankerplads, forend vi lettede. 



I den nedenstaaende Tabel betegner G Capt. Grieg 

 og M Mobn; E betegner den Expeditionen tilhørende Sex- 

 tant og S en Skibet tilhørende Sextant. ■ 



Hver Iagttager bestemte sin Indexfejl. Jeg fandt 

 den for Troughtons Sextant den 31te Juli ved- Solen -f- 1' 

 38" og ved Horizonten -j- 1' 35". Benyttet er den første 

 Værdi. 



De fleste Observationer gjordes fra Hyttedækket. 

 Øjets Hojde regnedes her til 18 norske Fod eller 5.6 

 Meter. 



f Beregningen er benyttet Solradien etter Nautical 

 Almanac. Som det vil sees nedenfor, er den af Observå- 

 tionerne udledede Solradius større. 



Som Observationsuhr benyttedes dels Lommechroiio- 

 meter, dels Lommeuhre. der umiddelbart for eller eiter 

 hver Observationsrække sammenlignedes med Hovedchrono- 

 metret Reid. Hr. Tornoe. vor Chemiker. assisterede mig 

 ved flere Observationer, idet han noterede Uhret. Reids 

 Correction til Greenwich Middeltid beregnedes for Obsérva- 

 tionerne 



Juli 30 Juli 31 Aug. 1 



til -f 8»' 28/6 -f 8™ 29/2 -4- 8*" 30/2 



Efter foreløbige Beregninger sattes for Ankérpladsen 

 paa Østsiden ,/„ - 70° 58/0 og /„ = 0* 33™ 48/3 W. 

 Greenwich. 



Beliggehheden af Ankérpladsen paa Vestsiden er ret 

 nøje bestemt trigonometrisk i Fqrhold til Ankérpladsen 

 paa Østsiden. Ved Hjelp af Stormasténs Hojde. 18.6 

 Meter, der fra en Baad af Capt. Wille maaltes i Vinkel 

 til 4" 20/3,' fandtes Baadens Afstand fra Skibet = 245 

 Meter. Fra Baaden og fra Skibet (Mohn) sigtedes sam- 

 tidig til Toppen af "Fugleberget", én fremtrædende let 

 kjendelig Fjeldtop paa ( feris Vestside ved Mary Muss Bugten. 

 Vinkelen Fugleberg — Skib, seet fra Baad. var 86" 3/7, 

 Vinkelen Fugleberg — Baad, seet fra Skibet, var 90° 13/3, 

 hvoraf beregnes Afstanden fra Skibet til Fugleberget til 

 2/03. Fuglebergets Azimuth fra Skibel fandtes etter 3 

 Compas-Pejlinger paa 3 forskjellige Kurser = X. 25° AV. 

 Deretter ligger Fugleberget 1' 50."4 nordligere og 2' 38. "0 

 vestligere end Ankérpladsen paa Østsiden. Fra Fugleber- 

 gets Fod maalte jeg den.29deJuli Masthøjden til 0° 55/5. 

 hvilket giver en Afstand af 0/62. Skibets Azimuth fra 

 Fugleberget var ber omtrent 70°. Eeraf beregnes, at 



The following day. July 31st, the Expeditkm anchored 

 in Great Wood Bay. on the east coast of the island. The 

 swell preventing us from landing. Capt. Wille and myself 

 took a series of solar altitudes on board, with different 

 sextants. The atmospheric conditions were not favourable. 

 cloud and mist repeatedly blotting out the sun or the 

 horizon. 



On the Ist of August the weather cleared a little, 

 and in the forenoon a few solar altitudes were observed 

 from the same anchorage. shortly before we got under 

 weigh. 



In the Table given . below, G signities Capt. Grieg. 

 and M, Professor Mohn; E signities the sextant belonging 

 to the Expedition, and S a sextant belonging to the vessel. 



Each observer determined his index-error. For the 

 Troughton sextant. I found the index-error. on the 31 st 

 of July. to be + 1' 38" by the sim. and + 1' 35" by the 

 horizon. The first of these values was applied. 



Most of the observations were made from the deck 

 of the roundhouse, where the eye of the observer was as- 

 sumed to be 18 Norwegian feet. or 5. (i metres, above the 

 sea-level. 



■ For these computations, the sun's semidiameter was 

 tåken from the Nautical Almanac. As will appeal- in the 

 sequel. that deduced from the observations was somewhat 

 greater. 



We observed with the pocket-chronometer and ordi- 

 nary watches. each timepiece beihg compared, immediately 

 before and after a series of observations. with our chief 

 chronometer. the Reid. Mr. Tornoe. chemist to the Ex- 

 pedition, assisted me in several of the observations. by 

 noting the indications of the watch. The Reid correction 

 to Greenwich mean time was computed for the observa- 

 tions tåken — 



July 30 July 31 Aug 1 



at -j- 8™ 28/6 -f 8™ 29/2 + 8 m 30/2 



For the anchorage on the east coast of the island, 

 I put. as the result of preliminary computations. if = 

 70" 58/0 and /.„ = 0* 'å3 m 48/3 W. Greenwich. 



The position of the anchorage off the west coast of 

 the island relative to that of the anchorage on the easl 

 side. was determined trigonometrically witli tolerable exact- 

 ness. Taking the height of the mainmast. 18. ti metres. 

 which. as measured from a boat by Capt. Wille. gave an 

 angle of 4" 20/3, the distance of the boat from the ship 

 was found to be 245 metres. From the boat .and from 

 the ship (Prof. Mohn), we simultaneously observed the sum- 

 mit of the -Fugleberg" (bird-cliff), a conspicuous riioun- 

 tain-top on the west side of the island, in close proxiinity 

 to Mary Muss Bay. The angle Fugleberg -ship, as de- 

 termined from the boat. was 86° 3/7; the angle Fugleberg— 

 boat. as determined from the ship. 90° 13/3; and with these 

 results the distance from the ship to Fugleberg was com- 

 puted at 2/03. The azimuth of Fugleberg from the ship, 

 we found from '■'• compass-bearings on 3 different courses 

 = X. 25" W. The Fugleberg should accordingly lie r 

 50. "4 ful her north and 2' 38."0 farther west than our 



