- Søbarometret Adie 1498 opbevaredes 1 sin Kasse paa 
Observatoriet i Bergen og opstilledes i Juni 1877 ombord 
i *Vøringen” paa samme Plads som tidligere. Dets Correc- 
tion controlleredes før, under og efter Rejsen ved Sammen- 
ligning med Stationsbarometer Adie No. 1506, hvis Correc- 
tion var fundet i Christiania 1 April 1877 at være = 
—0,”m42, og i Maj 1878 fandtes = —0.””41. De ombord 
i *Vøringen” gjorte Sammenligninger gave følgende Resul- 
tater. 
1877. Lufttryk (Pressure). 
The marine barometer Adie No. 1493, was kept in 
its case at the Bergen Observatory, and in June 1877 
mounted on board the *Vøringen” in the same place as on 
the previous cruise. ‘he correction of the instrument was 
controlled before, during, and after the cruise, by compa- 
rison with the station barometer Adie No. 1506, for which 
the correction had been found in Christiania, in April 1877, 
— Q.mm42. and in May 1878 = — 0.7741. The com-'* 
parisons made on board the *Vøringen” gave the following 
results: — 
Corr. for Adie No. 1493. 
Juni (June) 8 Bergen 759.2" — 0.60”” 9 Observationer (Observations). 
Aug. 16 Bodo 759.5 — 0.52 | 
Sot SAG ale 758.1 GB == OG 
18» 757-7 =o99 | 
» 21 Christiansund 756.7 — 0.69 2 = 
» 23 Bergen 753.2 — 0.58 
Middel (Mean) 737 05 = oÖT (MF — + 0.067) 
Reduction til Havfladen (to the Sea-level) + 0.13 
Correction i (vn) 1877 — 0.48 
Søbarometrets Correction synes saaledes at være steget 
lidt siden 1876. Observationernes Beregning for 1877 fore- 
toges med den samlede Reduction af — 0.””5, 
I 1877 var paa Hyttedækket opsat et Bestikhus (Fig. 
1, Fig. 2, h). Inde i dette opsatte jeg, paa den agterste 
Veg, et godt Aneroidbarometer, der var forsynet med 
Thermometer. 
Dette Instrument blev for Fremtiden benyttet af Iagt- 
tagerne til Observation af Lufttrykket. De herved opnaaede 
Fordele vare dels, at Iagttageren ikke behøvede at forlade 
Deekket, for at udføre de meteorologiske Iagttagelser. dels 
at man undgik Tidsspilde, naar Søbarometret pumpede, i 
hvilket Tilfælde Aflæsningen af Aneroidbarometret kunde 
noteres lige saa sikkert paa 0.””1 som i roligt Vejr, og 
ligesaa hurtigt. Det indskjærpedes Iagttagerne, at notere 
Instrumentets Temperatur først, at banke paa Aneroidba- 
rometret før Aflæsningen, og at stille sig med Øjet centralt 
foran Skiven. 
Selv overtog jeg at holde stadig Control med Ane- 
roidbarometrets Stand. Til det Øjemed observerede jeg, 
hver Dag Søen var rolig nok, til at Søbarometret nede i 
Arbejdssalonen ikke pumpede og saaledes kunde aflæses 
Den norske Nordhavsexpedition. H. Mohn: Meteorologi. 
Hence, the correction of the marine barometer would 
appear to have inereased slightly since 1876. The com- 
putation of the observations for 1877, were made with the 
aggregate reduction of — 0.775, 
In 1877, a deckhouse (see Fig. 1, Fig. 2, h) was 
erected on the spar deck. Here, on the after bulkhead, I 
had mounted a good Aneroid barometer, provided with a 
thermometer. 
This instrument was subsequently used for observing 
the atmospheric pressure. The advantages thus. obtained 
lay partly in the observer not having to leave the deck to 
take the meteorological observations, and partly in a con- 
siderable saving of time when rough weather caused the 
marine barometer to pump, since the readings of the Ane- 
roid barometer could in such case be noted as accurately, 
within 0.””[, as in calm weather, and as quickly. The 
observers were expressly told, first to read off the temper- 
ature of the instrument, to tap the Aneroid barometer 
previous to noting its indications, and to have thei eye 
fixed centrally before the disk. 
I undertook myself to keep the error of the Aneroid 
at all times controlled. With this object in view, I observed 
every day the sea was sufficiently calm to keep the marine 
barometer from pumping, and thus admit of its being read 
D 
