I. 
Havets Temperatur. 
I. De benyttede Instrumenter. 
Angaaende lagttagelsen af Havoverfladens Temperatur 
henvises til min Afhandling ,Meteorologi* Side 46. 
Til Expeditionens første Rejse i 1876 var anskaffet 
10 Miller-Casella’s Dybvandsthermometre af den alminde- 
lige Construction og Størrelse (Indfatningsrammen 23 cm.). 
Disse Instrumenter ere nu saa ofte beskrevne!, at det ikke 
her er nødvendigt at beskrive dem nøjere. De vare ind- 
delte i Celsius-Grader og prøvede ved et Tryk af 2.5 
Tons pr. Kvadrattomme. De fra Fabrikanten opgivne 
Correctioner for Tryk kom, som senere skal omtales, ikke 
til Anvendelse ved Observationernes endelige Beregning. 
De 9 af disse Instrumenter, der jevnlig anvendtes paa 
alle Expeditionens tre Togter, 
ved Romertallene I til IX. 
I 1876 og 1877 anvendtes nogle faa Gange et Dyb- 
vandsthermometer af Negretti & Zambra.? Det er U-formet 
og havde en Vendemekanisme, der ved Ophaling virkede 
gjennem en Skruepropeller. Da den oprindelige Vende- 
mekanisme virkede saa hurtigt, at man var udsat for, at 
Thermometret under Søgang kunde vende sig, og derved 
registrere Temperaturen, førend det havde accommoderet 
sig, blev Mekanismen af Capt. Wille til Rejsen i 1877 
forandret til en langtsomt virkende. Ved Temperaturrækker 
haledes da Lodlinen, efterat Thermometret havde accom- 
moderet sig i Dybet, ind nogle Favne og firedes atter 
ud, hvilket gjentoges saamange Gange, at man var sikker 
paa, at Thermometret var vendt. Derpaa begyndte den 
egentlige Indhaling. En saadan Operation tog megen Tid, 
hvorfor Instrumentet sjelden anvendtes. 
tegnes 1 det Foleende ved N Å. 
ere 1 det folgende betegnede 
Instrumentet be- 
1 Se f. Ex: Wyville Thomson. The Depths of the See. S. 291. 
2 Beskrevet 1 “Nature,” Vol IDK, Sh BT 
Den norske Nordhavsexpedition. H. Mohn: 
Nordhavets Dybder, Temperatur og Stromninger. 2 
I. 
Temperature of the Sea. 
i. Instruments. 
Respecting the observations taken of the tempera- 
ture of the sea-surface, I refer to my Memoir — *Meteoro- 
logy,” p. 46. 
For the first cruise of the Expedition, in 1876, had been 
provided 10 deep-sea Miller-Casella thermometers, of the 
usual construction and size (frame 23 em.). These instru- 
ments have been so often deseribed! as to ‘render further 
description here superfluous. They were divided in de- 
grees centigrade, and had been tested by a pressure of 2.5 
tons per square inch. The corrections given by the in- 
strument-maker were not, as will be subsequently explained, 
made use of when finally reducing the observations. Of 
instruments, the 9 im constant use on each of the 
3 cruises of the Expedition will be indicated by the Roman 
letters I to IX. 
In 1876 and 1877, a deep-sea thermometer by Ne- 
these 
gretti and Zambra was used on a few occasions.? This 
instrument is U-shaped and furnished with a mecha- 
nism for turning over in the water, which, on hauling 
it in, acts by means of a small propeller. The orig- 
inal mechanism operating with such rapidity that in a 
heavy sea the thermometer was lable to turn over and 
the temperature before the 
accomodate — Capt. Wille gave it, for 
1877, a slower-acting mechanism. 
register instrument could 
the cruise in 
When measuring serial 
few 
temperatures, the sounding-line was hauled in a 
fathoms, as soon as the thermometer had been given 
time to accomodate in the deep, and then veered out 
again, the operation being repeated sufficiently often to 
ensure the thermometer having turned over. Then com- 
menced the final hauling-in. An operation of this kind 
naturally took up a great deal of time, and hence the 
instrument was seldom made use of. 
will be indicated by the letters N Z. 
This thermometer 
1 See, for example, Wyville Thomson. The Depths of the Sea, p. 291. 
? Described in “Nature,” Vol. IX. p. 387. 
