312 Meteorological Observations at Hudson, Ohio. 
According to observations for five years at Montreal, by Mr. 
M’Cord, the mean pressure was greatest in autumn and least in 
summer, the difference being .090. This coincides in part with 
my own result. The fluctuations of the barometer are however 
so great and seemingly anomalous, that observations need to be 
continued for a long period to establish any general law. The 
mean pressure at Hudson for the three years is 28.806 inches. 
In order to appreciate the value of this result, we must compare 
it with observations made at other stations. The following table 
exhibits the mean pressure of the atmosphere at the places 
named, according to M. Schouw, the heights being reduced to the 
level of the sea at the temperature of 32° F’., and corrected for 
the change of gravity in different latitudes. The table is found 
in the Comptes Rendus des Séances de |’Académie, 1836, i, 573. 
Latitude. Barom. ’ Place. Latitude. — 
33° 56/s. |30.008 | London, 51° 28'n.|: 
22 56’s.| .026]} Altona, 53 32 
24’n.|29.849 | Dantzic, 54 21 
48 .856] Kénigsberg, |54 43 
ard 019 Reikiavig, 64 00 
‘52 | .003/Godthaab, (64 00 
AT (29.993 Eyafiord, 65 50 
56 | .999;)Godhavn, 68 00 
30 (30.006; Upenavik, (73 00 | 
> 24 -007 | Melville Isl. (74 30 
48 50 [|29.988]Spitzbergen, !75 30 
The denis of the barometer near the equator, as well as 
in high northern latitudes, is strikingly exhibited by this table. 
With this standard let us compare some observations made in 
this country. The data for New York are furnished by Mr 
Redfield, Am. Journal, vol. xxxviii, p. 326. ‘Those for Mon- 
treal, by Mr. M’Cord, being the mean of five years’ observations, 
po a for Quebec by Mr. Watts, N. Y. Regents’ Report for 
: The reduction. to the level of the sea was compu- 
Laplace, Mee. Cel. vol. iv, p: 572; and 
e formula H=H’ 
