568 THE INTELLECTUAL RISE IN ELECTRICITY. 



tion, the material theory of the lightning which Aristotle 

 had propounded gradually replaced the imaginative one. 

 The flame came to be regarded as fire not ordinary fire, 

 but what Jerome Cardan 1 calls the "fire of fires." Fire, 

 he says, which is hotter than any other differing from 

 any other because the mere touch of it kills the "fire of 

 thunder." It will melt the very money in your purse, 

 and yet so subtly as not to harm the purse itself. It 

 enters the metal and tears it asunder. Then he has this 

 curious passage: 



"And this kind of fire must necessarily have great 

 velocity in solid matter. Indeed, why does the thunder 

 never touch columns or sink ships? It seldom touches 

 them, although once I saw in Florence, at the great 

 church, a column broken and shattered by the thunder; 

 but it does not strike them often, nor throw them down, 

 because the blow glances because of the rotundity. Sim- 

 ilarly, it seldom strikes the bottoms of ships, because it 

 cannot penetrate more than five cubits below the surface 

 of the earth; and the bottom of the ship is low and the 

 mast is high, and this last is often struck. A certain 

 remedy against thunder is to hide in deep caverns, and 

 this is more sure than to crown oneself with sealskin or 

 the skin of an eagle, or to carry a hyacinth stone; for it is 

 said that these things are not touched by thunder. But I 

 have known a laurel to be injured by thunder in Rome." 



Observe that in Cardan's time the idea of possible pro- 

 tection against lightning had become thinkable thanks, 

 perhaps, to the Reformation and the power is supposed 

 to lie in the hyacinth stone, "which protects men from 

 the thunder;" and this "is no small power, seeing the 

 many noble personages who have thus suddenly perished 

 Zoroaster, King of the Bactrians; Capaneus, in the 

 Theban War; Ajax, after the destruction of Troy; Anas- 

 tasius, the Emperor, in the 27th year of his reign; Carus, 

 also, and other emperors. Let us consider how this can 



1 De Subtilitate, Lib. ii. 



