Dækket brudt ved et foran eller agtenfor Skorstenen op- 
hengt Røgsejl, der enten fordelte Rogen eller nødte den 
til at stige saa højt tilvejrs, før den gik agterover, at den 
ikke rørte Thermometerhuset. 
Med Vinden paa Bougen, tvers eller paa Laaringen 
kom Luttstrømmen altid frit fra Havet til Thermometer- 
huset. Med Vinden næsten eller ganske ret agterind kunde 
det tænkes, at det opvarmede Fartøj og navnlig Skorstenen 
kunde give den Luftstrøm, som naaede Thermometerhuset, 
en for høj Temperatur. Samtidige Iagttagelser af Thermo- 
metre, opstillede ganske paa lignende Maade agterud ved 
Roret (Fig. 2, 2), viste imidlertid, at Thermometrene forud 
under Fokkestaget viste samme Temperatur som de agterud, 
naar Vinden var agterind. Dette Resultat skyldtes væsent- 
lig den Højde, i hvilken Thermometrene forud hang, thi 
med Vinden forind viste Thermometrene agterud. der stode 
i Mandshøjde over Dækket, i Regelen højere end de forud. 
De til Lufttemperaturens og Fugtighedens Bestem- 
melse benyttede Thermometre vare af Aderman i Stock- 
holm. De vare hvert Aar sammenlignede i Christiania ved 
det meteorologiske Institut med Normal-Thermometer, der 
er os sendt fra Kew-Comiteen. De vare inddelte 1 1/; 
Grad og de fundne Correctioner mindre end 0.91. Til 
Thermometerhuset under Fokkestaget udvalgtes 2 Thermo- 
metre, hvis Correctioner vare under 0.005. 
I 1876 og tildels i 1877 gjorde jeg nogle sammenlig- 
nende Forsøg med Slyngethermometer og vort tørre Ther- 
mometer forud. Slyngethermometret svingedes oppe paa 
Forkant af Hytten, i samme Højde som Thermometret i 
sit Hus under Fokkestaget. Resultatet af disse Forsøg 
var følgende: 
= 
| 
| 
87% Jun 20, 76 pin 
(June) 30. o pm. 
Muli 2, 7 ppm 
(July) 3. 7 pm. 
3 » & pi 
. Fo UO Di. 
1877. dum 2 © pp 
(June) 15. 11 am. 
5 38 jon 
45 
Slyngetherm. 
(Sling Therm.) 
Corr. 
11.°8 
1220 
IT. 
Tt. 
Sms ono DST MA 
of such smoke was as a rule in a great measure counteracted 
by a smoke-sail hoisted either before or behind the galley- 
funnel, this sail either dissipating the smoke, or compelling 
it to ascend so far up before passing aft that it did not 
come in contact with the thermometer-case. ‘ 
With the wind on the bow, on the beam, or on the 
quarter, the current of air reached the thermometer-case 
unopposed from the sea. With the wind almost or right 
aft, it might be supposed that the heated vessel, and more 
especially the funnel, could impart to the current of air on 
its reaching the thermometer-case too high a temperature. 
Simultaneous observations of thermometers mounted aft in 
proximity to the rudder (Fig. 2, z) precisely as described 
above, showed, however, that the thermometers under the 
fore stay indicated the same temperature as those mounted 
aft, when the wind came right over the taffrail. This result 
must be ascribed chiefly to the height at which the ther- 
mometers in the fore part of the vessel were suspended; 
for, with the wind right ahead, the thermometers at the 
stern of the vessel, 5 or 6 feet above the deck, indicated 
as a rule a higher temperature than those under the fore 
stay. 
The thermometers used for determining the tempera- 
ture and humidity of the air were by Aderman of Stock- 
holm. They were each year compared in Christiania with 
the standard thermometer of the Meteorological Institute, 
presented by the Kew Committee. These instruments were 
eraduated in fifths of a degree C., and the corrections did 
not amount to 0.91. For the thermometer-case 
under the fore stay, 2 thermometers were selected, for which 
the corrections were under 0.°05. 
In 1876, and occasionally in 1877, I made compara- 
mounted 
tive experiments with a sling thermometer and with the dry 
thermometer under the fore stay. The sling thermometer 
was swung on the fore part of the roundhouse, at the same 
height as the thermometer in its case under the fore stay. 
The result of these experiments was as follows: — 
Middel (Mean ). 
Tørt. , 
Forskjel. 
(Dry.) ip) Y 
Therm. 
WDD | — 004 | 1809 
øy 7) — 0.3 27 
| 12.0 — 0. 3 35 
| 20 + 0. 2 101 
10. 8 + 0. 3 102 
10. O 0.0 24 
RR Å + 0.2 45 
Op å + 0.1 (0) 
6.5 + 0.1 22 
— 0°01 
6* 
