The Middle Ages 45 



bands, larger toward the base, were narrowed at the summit, where 

 they terminated as a kind of monk's hood." ^ 



The number of displays recorded increased during the seventh to 

 tenth centuries, with the usual interpretation of bloody battles and 

 dire portents of public catastrophes. De Mairan (1733: 163) re- 

 gretted that it was necessary to resort to the work of astrologers to 

 obtain the old records, rather than the writings of astronomers, and 

 asked how much attention would have been paid to the aurora by 

 Isidore of Seville, had not Attila taken Europe by fire and blood 

 immediately afterwards. During the tenth to thirteenth centuries, 

 especially in Russia, the aurora borealis was regarded as a " struggle 

 of celestial armies coming to help and sustain those fighting on 

 earth," but during the fourteenth century, when the Russian gov- 

 ernment wished to colonize the northern regions of tundra, par- 

 ticularly beautiful displays were interpreted as divine commands to 

 erect churches or monasteries.^ 



Isidorus, Rahanus, and Hildegard 



An important source of knowledge during the Middle Ages was 

 the Etymologiae of Saint Isidore, Archbishop of Seville (ca. 560- 

 636) , an encyclopedia in twenty books, compiled from various 

 sources. It was quoted by Vincent de Beauvais (died 1264) and 

 others. Isidore gave nearly the same account of luminous stones as 

 did Pliny, referring to the carbuncle and also to a blue stone which, 

 " exposed in the day time becomes impregnated with rays of light." 

 The wording is such as to suggest phosphorescence but reflection of 

 light is just as probable. Among insects the cicindela * (firefly or 

 glowworm) is described as " a genus of beetles, which is said to 

 shine, either walking or flying." 



The glowworm was noticed by a number of subsequent writers. 

 During the Renaissance of Charlemagne (742-814) , Rabanus 

 Maurus {ca. 776-856) , the Praeceptor Germaniae, a monk edu- 

 cated at Fulda and Alkwin and later Archbishop of Mainz, described 

 cicindela, a lighting beetle, in his scientific reference book, De 

 Universo.^ 



2 Quoted from de Mairan (1733: 128) . 



^ See G. Sarton, Introduction to the history of science 3, 709-711, 1948, and the review 

 of the aurora borealis in Russian literature from an article by D. O. Sviatskii (1934) , 

 Isis 24: 282, 1936. 



* Spelled in different ways by different authors. In modern tiines, the name Cicindela 

 is used for a genus of tiger beetles, with brilliantly colored wing covers but not 

 Ivmiinous. 



^ Printed in 1617 (Coloniae Agrippinae) and in 1852 (Paris) . De universo was a 

 forerunner of the Speculum of Vincent de Beauvais. 



