SU 
af en Observation af Aneroidbarometret. Den støtste Af- 
vigelse mellem os er 0.””4, 
De 1 Observationstabellerne opførte Barometerhøjder 
for 1877 ere Styrmændenes Noteringer af Aneroidbaro- 
metret, reducerede til sand Barometerhøjde ved Havets Over- 
flade efter de her beskrevne Methoder. 
I 1878 anvendtes de samme Barometre, paa den samme 
Plads ombord og de samme Control- og Reductionsmethoder 
som 1 1877. 
Som Rejsenormal medfulgte Stationsbarometer Adie 
No. 1506, hvis Correction fandtes i Christiania | 
— O.7"41 i Mai 1878. 
—0. 371 Oct. 1878. 
Den første Verdi er anvendt. Desuden medtulgte 
Expeditionen et Fortinsk Barometer af Sécrétan, der oftere 
observeredes ved Siden af Adie 1506, naar Skibet laa roligt, 
tilsyneladende uden verticale Bevægelser. Dette sidste var 
en aldeles nødvendig Betingelse tor, at det Fortinske Baro- 
meter skulde kunne benyttes. Der skulde meget liden 
vertical Bevægelse til at bringe dette Instrument til at 
pumpe. Barometret Sécrétan stemte, naar dets i Christi- 
ania bestemte constante Correction anvendtes, ret godt med 
Adie 1506. Men som Controlbarometer var det, ophængt 
ombord i et Fartøj i Havne, som Hammerfest, hvor der 
næsten altid er en Smule Dynning, ikke fuldt tjenligt, 
hvorfor jeg ved Beregningen ikke har taget Hensyn til de 
med samme gjorte Observationer. Stationsbarometret Adie 
No. 1506 (Kew Model) derimod, var fortrinlig skikket til 
dette Brug, da dets Rør er indsnevret saa vidt, at det 
taaler en ganske svag Dynning uden at pumpe, paa samme 
Tid som det er langt folsommere end et Søbarometer. Ob- 
servationerne med Sécrétan vare dog forsaavidt af Værd, 
som de tjente til Control for, at Adie 1506 var i fuld 
brugbar Stand. 
De første Controlbestemmelser gjordes den 26de Juni 
1 Vardø, hvor Søbarometret observeredes ombord, medens 
jeg under Inspection af den meteorologiske Station samme- 
steds observerede Séerétan 1 Land. Begge Barometres An- 
givelser, reducerede til samme Øjeblik og samme Niveau, 
gave for Søbarometret en Correction af — 0.7762. Da disse 
Sammenligninger ikke vare directe, har jeg ikke medtaget 
dem i den følgende Tabel, ihvorvel deres Resultat kommer 
overens med det definitive. Den følgende Tabel giver de 
Værdier af Søbarometrets Correction, der ere fundne af 
directe Sammenligninger ombord, hvor begge Barometre 
hang ved Siden af hverandre. Rubrikken *Lutttryk” er 
Observationerne af Adie 1506, reducerede til 0°, og for- 
mindskede med 0.741, 
equal to the probable error, given above, of one observation of 
the Aneroid barometer. The greatest deviation occurring 
between my observations and those of the mates, is 0.4, 
The height of the barometer given in the Observation 
Tables for 1877, is the mates’ readings of the Aneroid 
reduced to true barometric pressure at the sea-level, ac- 
cording to the methods here set forth. 
In 1878, the same barometers were made use of, 
mounted in the same place on board, and the same methods 
of control and reduction applied as in 1877. 
As a travelling standard barometer, was taken out on 
the Expedition the station barometer Adie No. 1506, the 
correction for which had been found in Christiania to be 
—O."41 in May 1878, and 
—0. 37 in Oct. 1878. 
The first of these values was applied. Moreover, a 
Fortin’s barometer, by Sécrétan, was also taken out on the 
Expedition, the readings of which were also noted and com- 
pared with those of Adie No. 1506, when the vessel lay 
well-nigh motionless, and apparently without any vertical 
movement. The latter condition was indispensible to admit 
An exceedingly slight 
vertical movement would cause the said instrument to pump. 
The barometer Sécrétan was, on applying its constant correc- 
tion, determined in Christiania, found to agree pretty well 
of observing the Fortin barometer. 
with Adie No. 1506. Meanwhile, as a control barometer, 
mounted on board a vessel in port, — Hammerfest, for 
instance, — where there is almost always a little swell, it 
did not prove thoroughly serviceable; and hence, in making 
the computations, I had no regard to the observations taken 
with the said instrument. The standard barometer Adie 
No. 1506 (Kew model) was, on the other hand, excellently 
adapted for that purpose, its tube being so far contracted, 
that it will bear a slight swell without pumping, and is 
The 
observations taken with the Sécrétan instrument proved, 
however, so far of value, as they served to show, that the 
Adie barometer No. 1506 was in good order. 
besides far more sensitive than a marine barometer. 
The first control determinations were made on the 
26th of June, at Vardg, where the marine barometer was 
observed on board, while I, when engaged in inspecting the 
Meteorological Station of that place, observed the Séerétan 
instrument on shore. The readings of both barometers, 
reduced to the same moment and to the same level, gave 
for the marine barometer a correction of —0.””62. These 
comparisons, however, not having been undertaken direct, 
I have not included them in the following Table, notwith- 
standing their result agrees with that definitively found. The 
following Table gives the values of the correction determined 
for the marine barometer by direct comparison on board, 
where the two instruments were mounted side by side. 
The Column *Pressure” contains the observations taken 
with Adie No. 1506, reduced to 09 and diminished with 
Q.mm4l, 
