436 
METEOROLOGICAL OBSERVATIONS 
of the dry air at its maximum at 45° exceeds the equatorial gaseous pressure by 
about 0 - 47 inch ; the pressure of the whole atmosphere at its maximum in 35° is not 
more than 04 8 above the equatorial pressure. 
“The following Table contains the approximate mean annual pressures of the 
atmosphere corresponding to different latitudes, as given by Dr. Erman : — 1 . Of the 
barometer ; 2, of the vapour; and 3, of the dry air. The Table is formed from ob- 
servations in both hemispheres, and in both the Pacific and Atlantic Oceans ; it 
also unites observations made in different seasons, with a single exception. 
Latitude. 
Barometer. 
Tension 
of the 
vapour. 
Pressure 
of the 
dry air. 
Remarks. 
o 
inches. 
in. 
in. 
0 
29-98 
0-77 
29-21 
5 
30-00 
0-77 
29-23 
10 
30-03 
0-75 
29-28 
15 
30-07 
0-70 
29-37 
20 
30-11 
0-65 
29-46 
25 
30-14 
0-61 
29-53 
30 
30-15 
0-55 
29-60 
35 
30-16 
0-50 
29-66 
40 
30-12 
0-44 
29-68 
45 
30-03 
0-35 
29-68 
50 
29-90 
0-26 
29-64 
Winter only. 
55 
29-64 
0-22 
29-42 
“ The summer pressures of the dry air are less than file winter ones, except at the 
equator ; the contrary is the case with the vapour.” 
On comparing Dr. Erman’s conclusions with those drawn from the observations 
in the Pagoda, it appears that they agree in placing the maximum barometric pres- 
sure in lat. 35°, the pressure diminishing thence rapidly to 56°, where the Pagoda’s 
observations show it to become nearly stationary; but they differ as to the place of 
the maximum pressure of the dry air, that being in lat. 40° or 45° by Dr. Erman’s ob- 
servations, and in lat. 35° by those of the Pagoda. It is possible however that a 
longer series of observations would have made the present ones agree more closely 
in this respect also with those of Dr. Erman, his means being taken from observations 
made in different seasons, and in various longitudes in both hemispheres. Taking 
rom Dr. Erman’s table 29 - 21 as the mean pressure of the dry air at the equator, the 
observations in the Pagoda show a difference of gaseous pressure between the equator 
and the high latitudes ( — 56° to — 67°‘5) of the southern hemisphere amounting to 
0’28 inch ; the observations in the Pagoda were however exclusively in the summer 
months, when the pressures are generally less than on the mean of the whole year. 
Owing to the increase in the elastic force of the aqueous vapour in the warmer re- 
gions of the globe, the difference of barometric pressure between the equator and the 
high latitudes (taking the data from Dr. Erman’s table on the one hand, and from the 
observations in the Pagoda on the other) amounts to 0’89 inch. 
As the facts shown by these observations are curious, and must be interesting to 
meteorologists, it is hoped that the Royal Society will not consider this paper 
unworthy of their acceptance. 
