The Middle Ages 49 



other, fire sparkles from tfie water and the sailor imagines he is pro- 

 ceeding through a sea of fire." 



According to E. Wiedemann (1909) , the geographical Lexicon of 

 Jaqut mentions a place in Persia where rubies are found which 

 luminesce in the dark and Al Muquaddasi recorded stones which 

 luminesced at night. Wiedemann is inclined to think that tribo- 

 luminescent materials were known to the Arabs and that Arabic 

 alchemists must surely have run across calcium sulphide phosphors 

 in the course of their many chemical procedures. However, no 

 references are given by Wiedemann, although such things play a 

 part in Arab legends. 



Arabic science in Persia, Egypt, and other parts of the Middle 

 East began to wane in the latter part of the tenth century, but 

 continued to flourish in Spain and spread to western Europe. Much 

 of the knowledge was recorded by Adelard of Bath {ca. 1090-1150) , 

 the English natural philosopher, who lived for a time in Spain 

 and traveled widely in southern Europe. His book, Qiiaestiones 

 Naturales Perdifficiles, was published at Venice in 1472 and an Eng- 

 lish translation made by H. Gollancz (Oxford, 1920) . It unfortu- 

 nately contains nothing on luminescence, although questions on 

 such matters as " XII. Why some animals see more clearly by night 

 than by day," or " XX. Why men go bald in front," were answered 

 in a manner that can best be described as nonsense. 



Alhertus Magnus and the Encyclopedists 



During the thirteenth century revival of art and learning, again 

 with the exception of fireflies and glowworms, practically nothing 

 of special interest for the history of luminescence is to be found.^^ 

 Learning of the time was recorded in the great books of knowledge. 

 These enormous encyclopedic compilations had grandiose titles, such 

 as De Proprietatibus Rerum (written in 1230-1240 and published in 

 1470) by the Franciscan monk, Bartholomaeus (Bartholomew Glan- 

 vil, ca. 1190-1260) ; ^« or De Natura Rerum (written in 1228-1244) 



^^ In the generation following Adelard of Bath {ca. 1090-1150), the best-known 

 English scientist and the first English writer on zoology was Alexander Neckam (1157- 

 1217), the author of De naturis rerum libri duo {ca. 1190), whose natural history 

 was taken from Aristotle, Pliny, Solinus, Cassiodorus, and Isidore. The text has been 

 edited by T. Wright, No. 34 of the Chronicles and memorials of Great Britain and 

 Ireland during the Middle Ages, London, 1863. The glowworm, cicindela, does not 

 occur in the index. 



"The English translation of 1397 or 1398, Properties of All Thynges by John 

 of Trevisa (1326-1412), chaplain to Sir Thomas lorde of Berkeley, was printed by 

 Wynken de Worde in 1494. A later version by S. Bateman or Batman in 1582 was 

 " newly corrected, enlarged and amended." It was the first encyclopedia in the Eng- 

 lish language and a source of natural history knowledge in the Middle Ages and later. 



