REPORT ON METEOROLOGY. 
231 
to M. Carlini* * * § , whose Memoir is rather upon the general sub¬ 
ject of the variations of the barometer, than containing minute 
original observation, his register having been continued only 
for a short time ;—to the Geneva and St. Bernard Observa¬ 
tories, where the registers are kept with a regularity and pre¬ 
cision worthy of the greatest commendation, and which annually 
are affording data of the highest value for science f. I have 
already noticed the important fact that the mean annual oscilla¬ 
tion is actually reversed at the St. Bernard, 8000 feet above the 
sea. M. Escliman has since noticed that it is almost extinct 
on the summit of the Rigi J. 
Professor Hansteen has published some observations, con¬ 
tinued however for only six months, at Christiania, where he 
gives 0 mm -53 for the morning oscillation, and 0 mm, 40 for the 
evening §. 
M. Hallstrbm from observations at Abo, (likewise of too 
short continuance,) has endeavoured to deduce the principal 
oscillation, which he states at G mm *44; and he has attempted to 
assign in a general way the law of diminution from the equator 
to the poles ; it is however formed on imperfect data ||. A being 
the oscillation in latitude /, he gives 
V = 0*3931 - 2-3536 cos l + 4*5687 cos^ l 
for millimetres. This would give a positive oscillation, at the 
pole, of 0 mm '39, which is quite improbable. 
In 1828 I published some observations made by myself at 
Rome the previous year If. Though continued only for a short 
time, yet, as I frequently made twelve or fourteen observations 
in a day, I was enabled to trace out very well the diurnal curve of 
variation, establish the critical hours of morning and evening 
maxima and afternoon minimum, and give an approximation to 
the amount. 
Since that, I have investigated with great care, during the 
years 1827-30, the oscillation in latitude 56°,—the most north - 
* Memorie della Socicld Italiana, tom. xx. In this paper, which is of con¬ 
siderable length, M. Carlini has aimed at giving a type of the mode of treating 
such observations generally, rather than affording extremely accurate results by 
the analysis to which he has submitted his own, which were only continued for 
a few weeks in summer, and again in winter. These observations, however, 
having being made during part of the time every two hours, are well worthy of 
being consulted on their own account. 
f The annual means are regularly published in the Bibliotheque Vniverselle. 
X Bibliotheque Universelle, 1827. 
§ Bulletin des Sciences Mathematiques , ix. 32. 
li Poggendorff’s Annaleti,]! 826. Bulletin des Sciences Mathematiques, ix. 190. 
If Edinburgh Journal of Science , January and April 1828. 
