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of two large circles, which reprefent the 
two hemifpheres of the globe, fuppofmg it 
cut into two equal parts. The broad ex- 
ternal circles which furround thefe two he- 
mifpheres reprefent the horizon 3 that is, the 
imaginary circular line, which, if you were 
raifed fo far above the Earth as to fee one 
half of it, would divide the vifible from the 
invifible half. 
That ftraight horizontal line which di- 
vides the northern from the fouthern he- 
mifphere, is called the Equator: on the Earth 
it is an imaginary, and, on a globe, a real 
circle. The double circle which pafTes over 
the middle of New Holland, and that which 
you fee at the fame diftance from the Equa- 
tor on the north fide, are called the Tropics. 
The other two double circles near the north 
and fouth poles, are the Polar Circles. They 
are of ufe in Geography in determining what 
are called the Zones. The fpace between 
the two Tropics is the torrid-, between thofe 
and the polar circles, the temperate, and 
within thofe circles, the frigid Zones. 
In this, and in all other maps, the top is 
the north ; the bottom, the fouth', your right 
hand, the eaft; and your left, the wejl. 
Thofe circles, which you fee meet in both 
N 2 poles, 
