G70 
PROFESSOR JAMES THOMSON ON THE 
The continents and lands generally are not exhibited, and their disturbing effects on 
the atmospheric motions are left almost entirely out of consideration. The cir¬ 
culation imagined and described by Maury in connection with the diagram is meant 
to be a fair representation of what he would suppose likely to be realised in case of 
local and temporary disturbances and irregularities being only in a small degree 
effective. His supposed circulation may be thus described :—He supposes that the air 
entering the Belt of Equatorial Calms from the southern hemisphere rises there to the 
lofty regions of the atmosphere, and flows thence as an upper current to the Belt of 
the Calms of Cancer where it descends to the bottom, from whence it travels on as a 
south-west wind over the surface of the sea to the high latitudes round the Pole ; 
Fig. 2. 
M AU RY -1 855. 
and that then ascending at and near the Pole, it flows as an upper current out to the 
Calms of Cancer, where it sinks again to the bottom of the atmosphere crossing the 
current already mentioned as descending there, and then passes along the surface of 
the sea as a bottom current forming the north-east Trade Wind, and then enters the 
Belt of Equatorial Calms, rises there, crossing the previously mentioned rising current 
there, and thence departs as an upper current towards the Calms of Capricorn, to go 
through a circulation in the Southern Hemisphere which is an exact counterpart of 
that already described for the Northern Hemisphere. The supposed currents are 
further indicated by arrows in the diagram, which, on inspection, may easily be 
