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which its more rapid angular motion around the Sun enables itat such a time to overtake and pass by the Earth . It may alsobe noticed that the result is brought out by the diagram,without any mathematical calculations, simply by joining cor-responding places of the Earth and of the planet, and by pro-ducing the lines so drawn to meet the imaginary celestialsphere to which our eyes refer the place of the latter.
It follows, then, that as Venus travels between, or nearlybetween, the positions v 3 and v 8 , or for a certain distance oneach side of v 6 , one of its nearest approaches to the Earth , ! itwill appear to retrograde in the sky. And we may see that,
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at such a time, as observation also proves, its motion, as itgradually overtakes and passes the Earth , will seem to be muchslower than that which it will manifest when it is on theopposite side of the Sun, and moving in a direction the veryopposite of that of the Earth .
Moreover, it would also result, when the planet reverses itsapparent movement from progression to retrogression, and viceversd, that it must make a slight pause, and for a few daysmove so slowly as to seem to remain very nearly still. Thismay he further illustrated by a diagram (see Fig . XL.) of apart of its apparent path during the year 1884, deduced from theplaces given in the Nautical Almanac, in which year it will he