CHAPTER XL 



VENUS AND MERCURY. 



AMONG the planets of our system Venus is one which has 

 always been most tantalizing to astronomers. Notwith- 

 standing the fact that when this beautiful globe is seen at 

 its best it is far brighter than any star or any other planet^ 

 yet as a telescopic object Venus is often disappointing. It 

 shows, no doubt, the beautiful crescent which charmed 

 Galileo, when he first directed the newly invented tube 

 towards it, and the crescent of the evening star is still one 

 of the most pleasing telescopic spectacles, which speci- 

 ally delights the beginner who for the first time finds 

 himself in the possession of a telescope. But it is the 

 very brilliancy of Venus which often leads to disappoint- 

 ment. We see a radiant object, a beautiful gem of light, 

 but the brightness tends to prevent us from seeing the 

 actual features on the planet. In this respect we can 

 contrast Venus with another globe, namely, the planet 

 Mars. This body is our next neighbour on the outside, 

 just as Venus is the next neighbour on the inside. It is, 

 therefore, of particular interest for us to learn all we can 

 about the two bodies which are similarly situated witK 

 regard to the benefits which the sun dispenses so liberally 



