CHAPTER II 



THE MIDDLE AGES 



Introduction 



A FTER the period of advanced knowledge of the Greeks and the 

 -tx. Romans, which may be considered to end with Galen ^ (a. d. 

 131-200), comes the long gap of the Dark Ages and Middle Ages 



(a. D. 200-1400) with little original scientific observation, despite 

 the growth of Alexandrian and Byzantine centers of learning, and 

 the Carolingian renaissance. The intellectual mind was centered 

 on heaven rather than on nature and the influence of classical inter- 

 preters was paramount. No new luminous phenomena were observed 

 during the period, and mention of luminescence occurs chiefly in 

 connection with the sea, the aurora borealis, with luminous jewels, 

 and fireflies or glowworms (cicindelae) . St. Augustine (354-430) 

 and Gregory of Tours (544-595) both mention cicindelae, and 

 Gregory gave a minute description of the northern lights. 



The aurora borealis was without doubt the most spectacular exam- 

 ple of luminescence, although of infrequent appearance in central 

 and southern Europe. In Dortous de Mairan's great work on this 

 subject, L'Aurore Boreale (1733) , records of the aurora begin with 

 a statement of Nicephorus Callistus (fl. fourteenth century) , a 

 Byzantine monk, who reported in his Ecclesiastical History (Book 

 XII, Chap. 37) that a great number of " lances " or " jets of light " 

 were seen in the sky at night before the death of the Roman 

 emperor, Theodosius the Great (a. d. 346-395) . A second record, 

 with the return of similar celestial phenomena, is from the " History 

 of the Goths " of Isidore of Seville {ca. 570-636) around 447 a. d., 

 before the entrance of Attila (406P-453) into Italy and Gaul. A 

 third account, about 502, is to found in the Edessan Chronicles, 

 and a fourth, in 585, was described at great length in the Historia 

 Francorum (VIII, 7) by Gregory of Tours (Georgius Floretinus 

 Gregorius, 544-594) . He spoke of " brilliant rays of light in the 

 north, which seemed to come into collision and to cross the one with 

 the other, after which they separated and vanished." One great 

 display " took possession of part of the heavens and seemed to tra- 

 verse it . . . there was in the midst of the sky a luminous cloud, to 

 which all the rays combined in the form of a tent from which many 



^ Perhaps the fall of Rome (a. d. 476) or of Alexandria (a. d. 642) might be taken 

 as the beginning of the Dark Ages. 



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