Phosphorescence 313 



cats, the heads of certain fish, the mold of ships, and similar things " 

 which are not produced by a luminous body but have their own 

 light implanted by nature for certain definite ends. 

 He held that the Bolognian stone 



by the calcination and baking is purified of the admixture of earthly 

 dirt so that, when its crasser and denser substance has been purified 

 and attenuated, it becomes a body most fitted to receive through the 

 opening of its pores the vapors of which the air is full in the presence 

 of a luminous t)ody, whether from a fire or the full sun. If these sugges- 

 tions are accepted, then our stone, with its pores open because of the 

 calcination, thirsty on account of its dryness, naturally desires that vapor, 

 which is pregnant with its conception of light. And, just as a sponge 

 draws the neighboring water to itself, the white magnet draws slag, and 

 the similar bodies of the nature of gypsum attract wet lips, flesh, and 

 other things of humid nature; so it happens that the vapor now imbued 

 with light is attracted by the thirsty stone and is received into its pores.^- 



In short, Kircher's study of the Bolognian phosphor led him to 

 the belief that the material was made porous by the calcination 

 necessary for its preparation, thereby holding the subtile vapors of 

 air suffused with light in its pores as a sponge holds water. This 

 position was also taken in 1659 by his friend, Kaspar Schott (1608- 

 1666) , a fellow member of the Jesuits and a teacher at Palermo and 

 at Wiirzburg. Schott added nothing new to the study of the Bolog- 

 nian phosphor but, like Kircher, took a great interest in unusual 

 physical phenomena. 



NICOLAI ZUCCHI AND MID-SEVENTEENTH-CENTURY OBSERVATIONS 



The stone was mentioned by Thomas Bartholin (1616-1680) of 

 Copenhagen, but only casually, in his De Luce Animalium (1647) , 

 by Pierre Borel (1620-1689) in connection with his explanation of 

 the light of lamb's flesh at Montpellier, and by Olaus Worm (1588- 

 1654), also of Copenhagen, in his Museum, Wormianum seu His- 

 toria Rerum Rariorum (1655) . As the century progressed, " expla- 

 nations " of the light are more clearly expressed. After describing 

 the appearance of the Bolognian Stone, the method of preparing 

 the phosphor from it and how the phosphor behaves. Worm dis- 

 cussed the various theories regarding it, but added nothing new to 

 general knowledge. 



Apparently John Evelyn (1620-1706) was one of the first English- 

 men to learn of the marvel, as indicated by an entry in his diary. 

 During a visit to Bologna in late May 1645 he wrote: ^^ 



^'^ Diary and correspondence of John Evelyn, ed. by Wm. Bray, v. 1, London, 1819. 



