51 



Kroribmetrene stod i et Skal) i Arbejdssalonen om 

 Bagbord (Fig, 4, c). De blev optrukne hver Morgen og 

 derpaa indbyrdes sammenlignede. 



I 1S76 liavdes 3 Kronometre ombord, et at' Kullberg, 

 et af Mewes og et at' Frodsham. J ><-i første, der ved deri 

 paa Bergens Observatorium ai' Hr. Åstrand foretagne Un- 

 dersogelsc for Rejsen viste den jevneste Gang, blev benyttet 

 som Hoveduhr. 



I 1877 og 1878 liavdes 4 Kronometre ombord, nemlig 

 fortiden de 3 nævte. et af Reid. der var Skibet tilhørende. 

 Dette Kronometer viste en saa fortræflfelig jevn Gang, at 

 det benyttedes som Hoveduhr de 2 sidste Aar. 



Kronometrenes Stand blev bestemt, først paa Bergens 

 i (bservatorium (undtagen Reid) og senere hovedsagelig ved 

 de telegrafiske Tidssignaler fra Christiania. Disse Signaler 

 gives fra Observatoriet i Christiania hver Onsdag Morgen 

 Kl. 8 Formiddag og hver Søndag Morgen Kl. 9 Fonn.. 

 Greenwich Middeltid, til samtlige norske Telegrafstationer. 

 Signalerne gives paa Observatoriet direkte etter Normalpen- 

 delen. Der telegraferes hver Gang 3 Signaler, hvert be- 

 staaende af el enkelt Slag fra Nøglen paa Morses Tele- 

 grafapparat, nemlig 7* 59 m 0*, 8'' <)'" S og 8* 1 '" 0' om 

 Onsdagen og 8'' 59™ S , 9* 0'" S og 9* 1 '" S om Søn- 

 dagen. For at skille mellem Signalerne betegnes de hen- 

 holdsvis med 1, 2 og 3 dobbelte Slag strås eiter Signalet. 

 Paa Modtagelsesstationen, hvor man indfinder sig med sit 

 Kronometer eller Observationsuhr, hores Signalerne kort og 

 skarpt paa Morses Apparat. 



Ved 15 Par korresponderende Solhøjder paa Huse 

 (4" 36' 57" ost f. Greenwich) fandt Prof. Mohn den 10de 

 Juni 1876 Kronometret Kullberg * 38 m 43.3 * foran Green- 

 wich Middeltid. 



Under Expeditionens Ophold i Reykjavik toges af 

 Lieutn. Petersen og mig den Iste August 1876 14 Par 

 korresponderende Solhøjder paa en Plads, der ligger omtrent 

 200 Alen østenfor Kirken. Ifølge velvillig Meddelelse fra 

 Chefen for det Kgl. Danske Søkaart-Archiv, Hr. Komman- 

 dør Rothe, er, ifølge saavel ældre som nyere lagttagelser, 

 Længden af et Punkt, der ligger 600 Alen vestenfor Kirken 



21" 54' 46" W. Greenwich. 



Vor Observationsplads ligger saaledes ca. 800 Alen 

 øst for dette Punkt, hvilket, da Bredden er 64 ° 9', svarer, 

 til 38" i Længde, og Længden af vor Observationsplads 

 bliver saaledes 21° 54' 8" W. Greenwich eller i Tid: 



1 >' 27 " 36.»5 

 Kronometrets Stand for Stedets Middel- 

 tid faml tes 2'' 6™ 55.'7 foran 



altsaa dets Stand for Greenwich Mid- 

 deltid 



0* 39'" 19. s 2 foran 



frequently observed the sun at. midnight. The days on which 

 no oDservations could be tåken were very few indeed. 



The Clirniioviefcrs wc kept in a cupboard in the work- 



i ni. on the port side (Fig. 4, c). .They were wound up 



every morning, and duly compared. 



On the first cruise, in 1876, we had 3 chronometers, — 

 one by Kullberg, one by Mewes, aud one by Frodsham 

 That by Kullberg, which, previous to the departure of the 

 Expedition. Mr. Astrand, Director of the Bergen Observatory 

 had found to have the most uniform rate of the three, wa 

 our principal timekeeper in 1876. 



In 1S77 and 1878 there was a fourth chronometer, 

 one ut Reid's, belonging to the ship. This instrument 

 having a remarkably uniform rate, we made it our chief 

 timekeeper on the two last cruises. 



The error of each chronometer was Hrst determined 

 at the Bergen Observatory (saving that of the Reid), and 

 afterwards chiefly by comparison with the time-signals tele- 

 graphed from Christiania. The observatory of that city trans- 

 inits these signals every Wednesday morning at 8 a. m. and 

 every Sunday morning at 9 a. m., Greenwich mean time, 

 to all Norwegian telegraph-stations. The time is tåken at 

 the observatory direct from the standard-clock. Three 

 separate time-signals, each consisting of a single click, are 

 telegraphed, from the key of Morse's apparatus, at intervals 

 of one minute, viz.: -- Wednesdays, at l 1 ' 59 m S , 8'' 0"' 

 0», and 8'' 1 '" S ; Sundays, at 8* 59 m S , 9'' m 0*, and 

 9* 1™ S . To distinguish between the signals, they are 

 respectively indicated by double clicks, 1. 2, and 3, following 

 after the signal in the order of successioii. At the receiving 

 station. where the observer stands by with his chronometer 

 or hack-watch in hand, the signals come sharp and distinct 

 from Morse's apparatus. 



From 15 pairs of equal solar altitudes, tåken at Husø 

 (long. 4° 36' 57" E.) on the lOth of June 1876, Professor 

 Mohn found the error of Kullberg's chronometer, on Green- 

 wich mean time, to be 0'' 38™ 43.*3 fast. 



During the stay of the Expedition at Reykjavik, 

 Lieutenant Petersen and myself took 14 pairs of equal 

 solar altitudes, at a point about 140 yards east of the 

 cathedra! From information kindly furnished by Commo- 

 dore Rothe, Hydrographer to the Royal Danish Navy, it 

 appears that the longitude of a point 410 yards west of the 

 church, has been found, by earlier as well as recent ob- 

 servations, to be — 



21° 54' 46" W. 



Our post of observation was thus about 550 yards 

 east of this point, which corresponds, the latitude being 

 64 ° 9', to 38" in longitude. Hence, our post of observation 

 was in 



Longitude 21 ° 54' 8" W., or in time 1 * 27 m 36.'5 

 Error of chronometer on mean time of 



place 2'' 6'" 55. s 7 fast; 



therefore on Greenwich mean time 



'' 39 ™ 19.«2 fast. 



