Der er Tegn til, at de større Vindhastigheder gjøre 
e, for liden, og de mindre e, for stor, saaledes som man 
kunde vente. Allerede en Vindhastighed af 6” pr. Secund 
skulde gjøre e, 0.””14 for liden, en Vindhastighed, der er 
lavere end den gjennemsnitlige 1 alle 3 Expeditionsaar. Det 
synes ikke, herefter at dømme, at Thermometrene have 
manglet det nødvendige Luftdrag. Medens saaledes denne 
Tagttagelse taler til Gunst for Nojagtigheden af vore Luft- 
temperaturer, faa vore Fugtighedsbestemmelser finde sig i 
at være underkastede Virkningen af Psychrometrets Ufuld- 
kommenhed. Denne Virkning har dog paa Søen vistnok 
mindre at betyde, da den relative Fugtighed altid er stor. 
De i Observationstabellerne givne Værdier af Vand- 
dampenes Tryk og den relative Fugtighed ere beregnede efter 
Psychrometeriagttagelserne ved Hjelp af Jelinek's Tabeller. 
I 1876 og 1877 havde jeg, som allerede nævnt, et 
lignende Thermometerhus, som det under Fokkestaget. op- 
stillet paa Agterdækket lige ved Roret. Da Thermome- 
trene i dette viste overensstemmende med de forud i alle 
Tilfælder med Undtagelse af, naar Vinden var ret forind og: 
hele Skibets Varme strømmede agterover, bleve Thermome- 
trene agterud ikke aflæste til de regulære Observationstider, 
og 1 1878 vare de ikke opstillede. 
I 1876 havde jeg opstillet et Thermometerhus med 
Psychrometer, af den af Meteorological Office i London 
benyttede Model, paa Forkant af Hytten om Bagbord lige 
ved den Plads (Fig. 2, y), hvor man tog Vandets Tem- 
peratur. Dette Instrument viste en smuk Overensstem- 
melse med det under Fokkestaget hængende, naar det var 
i Skygge, men skinnede Solen det mindste paa Kassen, 
viste Thérmometrene for hojt. Da jeg ingen Anledning 
havde til at anbringe Skjærme mod Solen, blev Instrumentet 
ikke opstillet de følgende Aar. 
4. Skyernes Form noteredes paa samme Maade som 
ved det meteorologiske Instituts Land-Stationer. (Howards 
Betegnelser). 
5. Skydækkets Størrelse noteredes efter den sæd- 
vanlige Scala: 0 = klart, 10 = overskyet. 
6. Nedbørens Slags noteredes for hver Time i en 
særskilt Rubrik, med specielle Betegnelser for dens Styrke. 
Desuden noteredes i Anmerkningsrubrikken Nedbør, 
som faldt mellem Observationstiderne. 
45 
There are indications to the effect, that with greater 
wind-velocities e, is too small, and with smaller wind-yelocities 
too large, which was indeed to be expected. Even with a 
velocity of 6” per second, e, should be 0.””14 too small — a 
velocity lower than the mean for all three cruises of the 
Expedition. Hence, judging from this circumstance, the 
thermometers would not appear to have lacked the requisite 
draught of air. Thus, while this result argues in favour 
of the accuracy with which the temperature of the air was 
determined, we must, as regards our determinations of 
humidity be content to take them subject to the influence 
exerted by the imperfection of the psychrometer. This in- 
fluence, however, at sea is of minor importance, the relative 
humidity. being invariably great. 
The values given in the Tables for the force of vapour 
and relative humidity were computed, according to Jelinek’s 
Tables, from the observations taken with the psychrometer. 
In 1876 and 1877, I had, as previonsly stated, a ther- 
mometer-case similar to that under the fore stay mounted 
close to the rudder. The thermometer in the said case 
having always indicated the same temperature as those 
under the fore stay, save when the wind came right ahead 
and the whole heat of the ship was carried aft, they were 
not read off at the regular hours of observation, and in 
1878 they were not mounted. 
In 1876, I set up a thermometer screen with a psy- 
chrometer, the identical model adopted by the Meteorolo- 
gical Office in London, on the fore bulkhead of the round- 
house (port side of the vessel), in immediate proximity to 
the place (see Fig. 2, y) where the temperature of the 
sea-water was taken. This instrument exhibited a remark- 
able agreement with that suspended under the fore stay, 
when in the shade, but if the sun shone ever so little on 
the case, the thermometers indicated too high a temperature. 
Being without the necessary means of screening off the sun, 
the instrument was not set up the following’ year. 
4. The Form of the Clouds was noted in the same 
manner as at the Land Stations of the Meteorological In- 
stitute (Howard’s Nomenclature). 
5. The Amount of Cloud was noted according to 
the usual scale: 0 = clear, 10 = overcast. 
6. The Nature of the Precipitation was noted every 
hour, and entered in a separate column, with special symbols 
to indicate its force. 
Moreover, the nature of the precipitation that fell 
between the hours of observation was noted m the column 
for General Remarks. 
