105 
 Ffter denne findes: 
1 Maximum: -+ 0.""24, 
2 Å 
2 MBS TDL, 
+ 0.""06, 10% 15” p.m. 
Amplitude: 0.””53. 
Da den saaledes fundne daglige Periode for Lufttrykket 
paa Havet i Sommermaanederne er saa afvigende fra den 
ellers bekjendte Periode, kunde man fristes til at tro, at 
den ikke havde nogen reel Betydning, men at den beroede 
f. Ex. paa en mangelfuld Reduction at de observerede 
Verdier. For at undersøge dette Forhold har jeg gaaet 
frem paa følgende Maade: 
Ved Hjelp af de paa de norske meteorologiske Kyst- 
Stationer samt paa Færøerne og Island! 3 Gange daglig 
gjorte Barometer-lagttagelser lader der sig anstille en Sam- 
menligning mellem vore Resultater fra Havet og Barometrets 
daglige Periode paa Kysten. Idet jeg udtog af Observa- 
tionsrækkerne de Dage, der ere benyttede til Bestemmelsen 
af Perioden paa Havet, og behandlede Observationerne fra 
Kyststationerne aldeles paa samme Maade som de ombord 
gjorte, idet Middelværdierne for hver af de 3 Observations- 
klokkeslet corrigeredes for Barometrets absolute Variation 
fra Begyndelsen til Enden af hver Række af benyttede 
Dage, derpaa tog Medium af de tre daglige Observationers 
Media og beregnede hver af de 3 første Medias Afvigelse fra 
dette sidste Medium (positiv naar det første er højere end 
det sidste), fik jeg følgende Resultater: 
1876. 8 am. 2 DN, 8 p.m. 
Florø — 0.27 "mL 0.257" + 0.027", 
Christiansund —o.39  +0.21 +0.18. 
Brønø — 0.27 +0.23 + 0.05. 
Samtlige Stationer udvise et Minimum i Morgenti- 
merne og et Maximum om Eftermiddagen, ligesom Observa- 
tionerne fra Expeditionen. Tages Middel af de 5 Kyst- 
stationer, faar man 
From this we find: 
Al 15” 3.m. 
9 h 
1 Minimum: — 0.""29, 
2 - -+- OQ,mm( JD, 
Total Range 0.”"53, 
The diurnal period of the pressure of the air found 
at sea, as deseribed above, in the summer months deviating 
so widely from the period otherwise known, it might be 
reasonably supposed to have no real significance, but to lie, 
for instance, in a defective reduction of the observed values. 
With a view to investigate this question, I have proceeded 
0” p.m. 
- in the following manner. 
By referring to the barometrical observations taken 
at the Norwegian meteorological coast-stations and those 
at the Færoes and Iceland! (3 times a day), a comparison 
may be made between the results of our observations at 
sea and the diurnal period of the barometer on the coast. 
Extracting from the series of observations the days from 
which the period at sea was determined, I treated the ob- 
servations from the coast-stations precisely in the same 
manner as those taken on board, correcting the mean value 
of each of the 3 hours of observation for the absolute 
variation of the barometer from the beginning to the end 
of each series of days, after which I took the mean of the 
means of three daily observations, and computed the deviation 
of the first means from the said mean (positive when the former 
is higher than the latter), and obtained the following results: — 
8 am. 2 p.m. 9 p.m. 
Thorshavn 0.00” — 0.07" + 0.07”. 
Berufjord —0.24 +011 +0.14. 
All the stations show a minimum in the morning 
hours and å maximum in the afternoon, as with the obser- 
vations from the Expedition. If we take the mean derived 
from the 5 coast-stations, we get — 
8 a.m. 2pm. 8,9 p.m. 
‘ Kyststationer — 0.237 + 0.157" + 0.09”. Coast-Stations. 
Expedition 1876 — 0.04 +019 —o.16. Expedition. 
1877. 8 a.m. 2 Di, 8 p.m. 
Brønø 0.007” + 0.0677 — 0.067, 
Bodø — 0.09 +015 — 0.06. 
Tromsø — 0.16 —oor +o.rz. 
Middel (Mean) —o0.08 +007 0.01. 
Expedition 1877 — 0.23 +013 + 0.10. 
Altsaa utter begge Minimum om Morgenen, Maximum 
om Eftermiddagen. 
1 Meteorologisk Aarbog, udgivet af det danske meteorol. Institut. 
Den norske Nordhavsexpedition. H. Mohn: Meteorologi. 
Thus, both with a minimum in the morning and a 
maximum in the afternoon. 
1 “Meteorologisk Aarbog, udgivet af det danske meteorol. Institut.” 
14 
