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44
Slyngethermometret var inddelt i hele Grader, y er
Vindens Vinkel med Kursen. Nogen bestemt Afhængighed
af Forskjellen mellem begge Thermometre og Vinkelen y
kan ikke sees. I Gjennemsnit vise begge den samme
Temperatur. Middeltallet af Afvigelserne mellem begge, uden
Hensyn til Fortegn, er +0.°21. Dette Tal er ikke større,
end at det nok kan forklares af Observationsfejl,
Correc-tionsfejl og virkelig Forskjel mellem Temperaturen i
Ther-mometerhuset og over Hyttedækket. Forsøgene med
Slyngethermometret modsige saaledes ikke den Antagelse, at
Thermometret til Lufttemperaturen var anbragt paa en
hensigts-svarende Maade og paa en heldig Plads.
For muligens at kunne controllers
Psychrometerobser-vationerne medtog jeg et Daniell’s Hygrometer, forfærdiget
af Aderman i Stockholm. Dets Thermometre verificeredes
af mig i Christiania. Det opstilledes, naar der gjordes
Forsøg med det, paa Forkant af Hytten til Luvart. En
Assistent aflæste paa givet Signal det indre Thermometer,
medens jeg iagttog Duggens Tilsynekomst og Forsvinden.
Begge stode vi i Læ af Instrumentet. Observationen af
dette Instrument var ingenlunde let. Der skulde for hver
Gang flere Forsøg til, førend jeg fandt den rette Mængde
Æther, der gav et tydeligt Belæg af Dug, som kort efter
forsvandt. Naar denne Mængde var funden, toges en Række
Forsøg, af hvilke de nedenstaaende ere Middel. Jeg vil
efter dette ikke tillægge disse Forsøg, ligesom heller ikke
de ovenstaaende med Slyngethermometret, synderlig Vægt.
Resultaterne af Forsøgene vare følgende:
The sling thermometer was graduated in whole
degrees: y is the angle subtending between the direction of
the wind and the ship’s head. Any appreciable
dependence of the difference between the two thermometers and
the angle y cannot be detected. On an average, both were
found to indicate the same temperature. The mean of the
deviations between both, without regard to sign, is +0.°21.
These figures are not greater than errors of observation,
errors of correction, and the true difference in temperature
within the thermometer-case and above the roof of the
roundhouse, are amply sufficient to account for. Hence,
the experiments with the sling thermometer do not oppose
the supposition, that the thermometer for ascertaining the
temperature of the air was mounted in a suitable manner
and in a favourable place.
With the object of possibly controlling the
psychro-meter-observations, I took with me a Daniell’s hygrometer,
made by Aderman of Stockholm. The thermometers of
this instrument I verified myself in Christiania. It was
mounted, when experiments were to be taken, on the fore
part of the roundhouse, to windward. An assistant read
off at a given signal the inner thermometer, whilst I
observed the formation and disappearance of the dew. Both
of us stood on the lee side of the instrument. To observe
with this instrument was no easy matter. On each
occasion several experiments had to be made before I could
find the quantity of ether that gave a perceptible coating
of dew, which shortly after disappeared. Having found the
said quantity, I made a series of experiments, of which
those tabulated below are the mean results. To these
experiments, as also to those with the sling thermometer, I
will not attach any great value. The results were as
follows: —
Dag. (ftv.) Psyclirometer, Daniell’s Hygrom. e« — e, Vindhastighed, observeret. (Velocity oj Wind obeerued.)
Tørt. (D’ll) Vaadt. ( er Dugpunkt. <Iliw Fnint.) e»
1876. Juni 22. IOA 45" am. ■3-°5 12.»6 10.3" I 2."15 10.6— + 0.3- 7™ pr. See.
(June) „ 7 0 pm. 14. 9 13- 9 11.2 13- 5 11.5 + 0.3 6
,, 30. 0 15 piil. 12. 7 II. 2 9.0 9- 5 8.9 —■ O.I 7
Juli 2. 7 0 pin. 12.0 10.8 8.9 10. 5 9-5 + 0.6 14
(My) 8. 10 30 ain. II. 4 10. 6 9., 9.0 8.6 — 0.5 5
r - i 30 pm. II. 9 li. i 9-4 9- 4 8.8 — 0.6 I
25- 1 30 pm. 10. 6 8.4 6.8 7.0 7-5 + 0.7 7
» 26. 6 45 pm. 10. 25 9- 35 8.2 8.5 8-3 + 0.1 3
1877. Juni 14- 6 0 pm. 10. 9 10. I 8.7 10. 0 9.2 + 0.5 7
Middel (Mean). 9.07°"" 9.21""" +0.14""" 6.3™
ep er Vanddampenes Tryk beregnet efter Psychrometret
(Jelinek’s Tabeller), eh Vanddampenes Tryk beregnet efter
Dugpunktet.
ep is the force of vapour computed from the psychrometer
(Jelinek’s Tables); eh the force of vapour computed from
the dew-point.
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