I'HASKb Ol- VKMJs. 35 



disc being turned towards the earth at E. When at B, she would 

 appear half illuminated, as the enlightened hemisphere is now 

 partly turned from the earth. At C, she would appear either wholly 

 unilluminated or at best a 'slight crescent, since her enlightened 

 portion is now wholly or almost wholly turned from the earth, at 

 D, she would appear again half illuminated. These phases were 



not really observed in the case of Venus, although Copernicus 

 predicted they would be, when we could see Venus plainer, and this 

 was considered by some as an unanswerable argument against the 

 truth of his theory, while others maintained that the planets shone 

 by their own inherent light, and of course had no phases. Such 

 was the state of science when Copernicus died, but already the 

 dawn of a brighter clay was advancing. The use of spectacle 

 glasses was quite common, and many shops were engaged in 

 their manufacture. It is related that some children of a Dutch 

 optician, while playing with the spectacle -glasses one day, chanced 

 to arrange two at such a distance as gave a magnified but inverted 

 image of distant objects, and the optician following out the idea 

 thus accidentally presented, the telescope was first made in Hol- 

 land. Gallileo, at this time professor of Mathematics, at Padua, 

 heard of this wonderful tube, and immediately set himself to 

 work to construct one. In this he was eminently successful, and 

 in his hands it gave the death blow to the opposers of the system 

 of Copernicus. With the telescope, Venus was clearly ob- 

 served exhibiting the phases which Copernicus had predicted. 



