This brilliant planet is often visible in the daytime.  I was once delighted by seeing Venus looking down, a little after mid-day through the open space in the dome of the Pantheon at Rome.  It has never since seemed to me as if the home of all the gods was deserted.  Phoebus, Diana, Venus and the rest, thronged through that open upper door at noon of night or day.  Arago relates that Bonaparte, upon repairing to Luxemburg when the Directory was about to give him a fete, was much surprised at seeing the multitude paying more attention to the heavens above the palace than to him or his brilliant staff.  Upon inquiry, he learned that these curious persons were observing with astonishment a star which they supposed to be that of the conqueror of Italy.  The emperor himself was not indifferent when [Page 140] his piercing eye caught the clear lustre of Venus smiling upon him at mid-day.

This unusual brightness occurs when Venus is about five weeks before or after her inferior conjunction, and also nearest overhead by being north of the sun.  This last circumstance occurs once in eight years, and came on February 16th, 1878.

Venus may be as near the earth as 22,000,000 miles, and as far away as 160,000,000.  This variation of its distances from the earth is obviously much greater than that of Mercury, and its consequent apparent size much more changeable.  Its greatest and least apparent sizes are as ten and sixty-five (Fig. 53).

[Illustration:  Fig. 53.—­Phases of Venus, and Varions Apparent Dimensions.]

When Copernicus announced the true theory of the solar system, he said that if the inferior planets could be clearly seen they would show phases like the moon.  When Galileo turned the little telescope he had made on Venus, he confirmed the prophecy of Copernicus.  Desiring to take time for more extended observation, and still be able to assert the priority of his discovery, he published the following anagram, in which his discovery was contained: 

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  “Haec immatura a me jam frustra leguntur o. y.” 
 (These unripe things are now vainly gathered by me.)

He first saw Venus as gibbous; a few months revealed it as crescent, and then he transposed his anagram into: 

  “Cynthiae figuras aemulatur mater amorum.” 
 (The mother of loves imitates the phases of Cynthia.)

Many things that were once supposed to be known concerning Venus are not confirmed by later and better observations.  Venus is surrounded by an atmosphere so dense with clouds that it is conceded that her time of rotation and the inclination of her axis cannot be determined.  She revealed one of the grandest secrets of the universe to the first seeker; showed her highest beauty to her first ardent lover, and has veiled herself from the prying eyes of later comers.

Florence has built a kind of shrine for the telescope of Galileo.  By it he discovered the phases of Venus, the spots on the sun, the mountains of the moon, the satellites of Jupiter, and some irregularities of shape in Saturn, caused by its rings.  Galileo subsequently became blind, but he had used his eyes to the best purpose of any man in his generation.