THE ECLIPTIC. 



57 



the tropic of Cancer. A similar line D S, which passes through 

 J? 



the centre of the earth, and a point 23J south of the equator, 

 will trace out the circle C' S', called the tropic of Capricorn. .The 

 circle P E' P' E, will represent a meridian, or a great circle which 

 passes through the poles and the centre of the earth. Let S S', 

 be a great circle, (of course seen edgewise in the diagram) this 

 will represent the ecliptic which is inclined 23| to the equator 

 E E'. When the sun is at S in the ecliptic, his apparent diurnal 

 path in the heavens, as the earth turns around, will be the circle C 

 S ; and to a spectator at B, the sun would be directly vertical, or 

 overhead, at noon. If we suppose a little circle marked on the 

 earth, corresponding with C S, we can readily perceive, that, as 

 the sun is fixed, while the earth turns around, all those places 

 upon the %arth which lie in this circle, will have the sun vertical 

 at noon. But a^ spectator at A, nearer the north pole of the earth, 

 would have his Zenith, or highest point of the heavens, as at Z, 

 hence the sun would come to the meridian below the Zenith. 

 This is the case at all places north of the tropic of Cancer, or 

 south of the tropic of Capricorn. Suppose now the sun to have 

 moved in his orbit from S to O, he would then appear to rise at 

 the same time with the star O, and describe the diurnal circle F 

 G in the heavens, parallel to the equator, arriving at the meridian 



