72 SIXTEENTH CENTURY. rr. in. 



CHAPTER X. 



SCIENCE OF THE SIXTEENTH CENTURY (CONTINUED). 



Battista Porta Kircher Dr. Gilbert Tycho Brahe, the Danisl 

 Astronomer Rudolphine Tables Galileo on Mechanics and Phy 

 sics Summary of the Science of the Sixteenth Century. 



Battista Porta's Discoveries about Light, 1560. The 



next discovery in science was about Light, and it was made 

 by a boy only fifteen years of age. Battista Porta was born 

 in Naples in 1545. He was so eager for new knowledge, 

 that, when quite a boy, he held meetings in his house for 

 any of his friends to read papers about new experiments. 

 These meetings were called ' The Academy of Secrets,' and 

 in the year 1560, when Porta was fifteen, he published an 

 account of them in a book called Magia Naturalis or 

 * Natural Magic.' In the seventeenth chapter of this book 

 he relates the following experiment, which he had made 

 himself. 



He says he found that by going into a darkened room 

 when the sun was shining brightly, and making a very small 

 hole in the window-shutter, he could produce on the wall of 

 the room, opposite the hole, images of things outside the 

 window. These images were exactly the shape of the real 

 objects, and had always their proper colours; as, for example, 

 if a man was standing against a tree outside the house, the 

 green leaves of the tree and the different colours of the man's 

 clothes would be clearly shown on the wall. There was 



