45 



ildregnet af Skibsjournalens Opgaver over Klokkeslettet, da 

 Skrabe (Trawl) blev sat ud. da Loddeme blev slupne, da 

 man begyndte Bundskrabningen, da den endte, og Indhiv- 

 oingen begyndte, og da Skraben (Trawlen) kom op igjen, 

 viser, at en Skrabning paa L00 Favnes Dyb gjennemsnitlig 

 tog P/2 Time. paa 500 Favnes Dyb 4 1 , Time. paa L000 

 Favnes Dyb 7 1 /.; Time. paa 1500 Favnes Dyb LO 1 3 Time. 

 Eller, udtrvkt ved en Tilnærmelsesformel, kan man sige, al 

 Tiden for en Bundskrabning = 



1.5+ (Dybden —100-Fv.) 0.654 Timer. 



Denne Formel giver for en Dybde af 2000 Favne 

 en Tid af 14 Timer. Forresten kunde Tiden for en 

 Bundskrabning paa en vis Dybde være temmelig for- 

 skjellig, ettersom Manøvren idk mere eller mindre heldig. 

 Var Trawlen meget tung f. Ex., maatte der hives langsom- 

 mere ind. I 1878, da Trawlen mest var i Brug. vårede 

 gjerne selve Skrabningen Lengere end tidligere (2 Timer 

 mod l 1 2 Time). Og Trawlen var ofte meget tung. Det 

 viser sig af vor Statistik ogsaa, at Varigheden af den hele 

 Operation gjennemsnitlig i 1*7* var større end i 1*77. 



Overfladenet. Formlen de ovenfor beskrevne Fangst- 

 redskaber brugtes ogsaa meget hyppigt af Prof. Sårs et 

 Overfladenet, som bestod af en omtrent 1 Meter (3 Fod) 

 lang Pose af tin Kammerdug, spids i den ene Ende. og 

 aaben i den anden, der var nestet til en King af Messing- 

 traad. Til denne blev fastgjort i Hanefod en smækker 

 Line. Naar der ved Ankomsten til en Arbejdsstation blev 

 kommanderet •'Sagte", udkastedes Nettet, og det slæbte 

 etter Skibet under den aftagende Fart. Undertiden blev 

 det ogsaa blot kastet ud fra Fartøjet under Stilleliggen og 

 strax indhalet. 



Navigering. 



Til Expeditionen var anskaffet et Admiralitets-Xbwjrøs 

 fra England. Dets Plads var. som tidligere anført, strax 

 forenfor Bestiklugaret paa Hytten (Fig. 2 c). Dets Devia- 

 tion bestemtes ved Svingning af Skibet. i 1876 i Husø, i 

 1877 i Huso, ved Bøst og i Vestfjorden, i 187* i Bergen, 

 paa Kysten af Øst-Finmarken mer Vardø, udenfor Sørøen 

 ved Hammerfest, paa Ishavet vestenfor Beeren Eiland. 

 under Beeren Eiland. under Spidsbergens Sydkap, under 

 Grønlandsisen paa 76 1 /;.. Grads Bredde. Observationerne 

 blev beregnede eiter Arcbibald Smiths Methode strax etter, 

 at de var tagne, og Resultaterne anvendte til Bestemmelse 

 af Kursen. De benyttede Værdier af Misvisningen toges 

 af de norske, britiske og danske Søkarter, naar Misvisnin- 

 gen ikke var bestemt ved vore egne Observationer. 



strunient when down. Reference to the sbip's logbook. in 

 which were recorded the details of every operation. com- 

 prising the moment at which the di*edge (or trawl) was 

 put over, that at which the sinkers were let go, the actual 

 dredging was commenced and terminated, when the heaving 

 in began, and when the apparatus «as hauled on deck. — 

 shows the average time to have been as follows: - At a 

 depth of 1»»*» fathoms, 1 hour 30 min.; at a depth of 500 

 fathoni.s. 4 hours 30 min.; at a deptb of L000 fathoms, 7 

 hours 2ii min.; and at a depth of 1500 fathoms. 10 lunns 

 30 min. Or. expressed by an approximate formula, the 

 time required tor a dredging = 



1.5 -f (the depth —lon fathoms) 0.654 hours. 



For 2000 fathoms. this formula will give 14 hours. 

 Meanwhile, the time a dredging would occupy at an\ 

 given depth, was found to v a ry not a little according 

 to the greater or less success attending the opera- 

 tion. And moreover. if the trawl had got an exceptio- 

 nally heavy freight, the rate of heaving in had to be reduced. 

 In 187*. when chief use was made of the beam-trawl, we 

 as a rule kept the apparatus longer at the bottom than 

 on the two preceding cruises, and it otten came up very 

 heavy It appears, too, from the entries in the log-book, 

 that the average duration of a east of the trawl in 1878 was 

 greater than in 1*77. 



The Toic-Xet. — Among the apparatus for prosecut- 

 ing zoological work was a tow- or surface-net, of which 

 Professor Sårs made frequent use. It consisted of a coni- 

 cal muslin bag. 3 feet deep, attached to a stout brass ring. 

 which, by means of a crow-foot. was made tast to a line 

 of suitable thickness. Shortly before our arrival at an 

 observing-statiou. after the ship's way had been deadened, 

 Professor Sårs east out the tow-net, which was pulled 

 along after the vessel till she stopped. Sonietimes, he 

 merely threw it over and hauled it in when there was no 

 way on the ship. 



Navigating the Ship- 



An Admiralty-compass had been procured from Eng- 

 land for the Expedition. Its place, as previouslv stated. 

 was just forward of the chart-room on the roundhouse. 

 The deviation of the instrument we determined by swing- 

 ing the ship. — in 1876 at Huso; in 1*77 at Huso. at Rost. 

 and in the Vestfjord: in 1878 at Bergen, off the coast of 

 East Finmark (near Vardo). off Soroen (near Hammerfest). 

 in the Arctic Ocean (west of Beeren Eiland). off South 

 Cape, Spit/bergen, and off the Greenland ice-barrier, in 

 lat, 76" 30' X. Immediately on being tåken, the observa- 

 tions were computed by Arcbibald Mnith"s method. and 

 the results employed for shaping the ship's course. The 

 variation was tåken trom the Norwegian. British, or Danish 

 charts. when not previouslv determined by our own obser- 

 vations. 



