108 
Østlandet. Aar (Year). 
Dovre 16 1865—80 
Christiania 15 67—81 
Sandøsund 20 
Efter Observationerne fra det astronomiske Observato- 
rium 1 Christiania har Lufttrykket i Sommermaanederne et 
Maximum ved Kl. 9 Morgen og et Minimum ved Kl. 5—6 
Eftermiddag. Natte-Maximum og Minimum falde bort. Den 
hele Amplitude er henimod 0.””9, Dovre synes at have en 
lignende Periode; i Sandøsund synes Morgenmaximum at 
falde noget senere, ialfald begynder den raske Synken først 
efter Kl. 2 Eftm. Vi møde her, navnlig i Christiania, den 
bekjendte periodiske Gang med en temmelig stor Amplitude. 
Stille vi Christiania og det norske Hav sammen, efter Af- 
vigelserne fra Dagsmediet, faa vi følgende Tabel: 
6 
220 Å 
Christiania 
Norske Hav (Norwegian Sea) 
61—80 
8 
—+0.23 +0.26 +0.32 +0.35 +0.32 
—0.17 —0.29 —0.22 —0.12 —0.0I 
8 a.m. 2 p.m. 8 p.m. 
+024" —0.24"" — 0.01”, 
+ 0.44 — 0.16 — 0.28 
+ 0.19 + 0.16 — 0.35 
According to the observations taken at the Astrono- 
mical Observatory in Christiania, the pressure of the air 
in the summer months has a maximum at 9 o'clock in the 
morning and a minimum at 5 to 6 o’clock in the afternoon. 
The night maximum and minimum disappear. The total 
range is about 0.””9, Dovre would appear to have a 
similar period; at Sandøsund the morning maximum would 
appear to occur somewhat later; at all events, the rapid 
fall does not commence till after 2 o'clock in the afternoon. 
Here — particularly in Christiania — the known periodical 
variation has a rather large range. On comparing Chris- 
tiania with the Norwegian Nea, as regards the deviations 
from the daily mean, we obtain the following Table: — 
Forskj el (Difference) 
Mellem Middag og Kl. 10 Aften er der, samtidig, 
Overskud af Luft over Havet og det skorter paa Luft over 
Landet, mellem Midnat og Kl. 10 Formiddag er der, sam- 
tidig, Overskud af Luft over Landet og det skorter paa 
Luft over Havet. 
Til Oplysning om Lufttrykkets daglige Periode i Som- 
mermaanederne paa Randen af Grønlandshavet tjene føl- 
gende Resultater fra den svenske Expedition til Spidsbergen 
1872—73 og den tyske Expedition til Østgrønland 1869 
70. Efter de af Dr. A. Wijkander i “Observations météo- 
rologiques de lVexpédition arctique Suédoise 1872—73” Side 
98 meddelte timevise Observationsmedia for Juni findes 
(Mosselbay) følgende observerede Afvigelser fra Middel af 
KIL & 2 og os 
+.0,05 0.00 — 10.06 
altsaa et Formiddagsmaximum og et Eftermiddagsmini- 
mum. 
Ved gratisk Udjevning findes endvidere: 
Maximum KI. 11 a.m. 10.087” Minimum K1. 7 p.m. — 0.11” 
Midnat + 0.05 = » 6 a.m. —O:01 
Perioden er altsaa den sædvanlige, med noget for- 
sinkede Epoker for Vendetidérne. Amplituden er liden, 
aa (Opa 18). 
Efter de af Capt. K. Koldewey i “Zweite Deutsche 
Nordfahrt IV, Meteorologie und Hydrographie,” Side 604 
--0.40 0:55 10.54 90.47 +-0.33 
10 12 20 Al 6 8 10 12 p.m. 
=|-0.09 —0.2'5 0.50 —0.53 = 0.37) -—0.08) 0.10 
+0.15 -+0.24 +0.20 +0.12 +0.06 +0.06 0.00 
—0.06 og —0.70 —0.63 —0.43 —0:14 0.16 
Between noon and 10 p.m. there is simultaneously a 
surplus of air above the sea and a comparative lack of air 
above the land; between midnight and 10 a.m. there is a 
surplus of air above the land and a comparative lack of air 
above the sea. 
With a view to elucidate the diurnal period of the 
pressure of the air in the summer months at the borders of 
the Greenland sea, I will here cite the followmg results ob- 
tained on the Swedish Expedition to Spitzbergen, 1872 and 
1873, and on the German Expedition to East Greenland, 
1869 and 1870. From the hourly observed means for June 
(Mossel Bay), communicated by Dr. A. Wijkander in “Ob- 
servations météorologiques de l’expédition aretique Suédoise, 
1872 — 1873,” p. 98, are found the following observed 
deviations from the mean of 8”, 2”, and 8”. 
JE O00 —003, 
accordingly a maximum in the morning and a minimum in 
the afternoon. 
Furthermore, drawing a free hand curve I 
by 
found: — 
ro 
Maximum 11 am. + 0.087”: Minimum 7 p.m. — 0.11”. 
ao 12 pm. +05 ; is 6 am. — 0.01. 
The period is therefore that commonly found, with 
somewhat retarded epochal hours. The total range is small, 
only 0.7719, 
According to the means for every alternate hour during 
the months of June, July, and August, communicated by 
