18 THE KING'S MIRROR 



In this theory there is nothing new or original : the be- 

 lief that the earth is of a spongy constitution and that 

 earthquakes are caused by air currents is a very old one, 

 which can be followed back through the writings of 

 Alexander Neckam,* the Venerable Bede,f and others, 

 at least as far as to Isidore.! The elder Pliny, who wrote 

 his Natural History in the first century of the Christian 

 era, seems to have held similar views: " I believe there 

 can be no doubt that the winds are the cause -of earth- 

 quakes." 



The chapters that deal with the northern lights are 

 interesting because they seem to imply that these lights 

 were not visible in those parts of Norway where the 

 King's Mirror was written. The editors of the Christi- 

 ania edition of this work call attention to the fact that 

 there have been periods when these phenomena were 

 less prominent, and suggest that there may have been 

 such a period in the thirteenth century. || The author 

 discusses these lights as one of the wonders of Green- 

 land, and the natural inference is that they were not 

 known in Norway. But it is also true that he speaks of 

 whales as if they were limited to the seas about Iceland 

 and Greenland, which is manifestly incorrect. It is 

 likely that the author merely wishes to emphasize the 

 fact that the northern lights appear with greater fre- 

 quency and in greater brilliance in Greenland than any- 



* De Naturis Rerum, 158. 



t De Natura Rerum, c. xlix: Migne, Patrologia Latina, XC, 275-276. 



t De Natura Rerum, c. xlvi: Migne, Patrologia Latina, LXXXIII, 1015. See 



also The Christian Topography of Cosmas (written about 547), 17-18; Cosmas 



scoffs at the theory. 



Naturalis Historiae, I, 201 (ii, c. Ixxix). 



|| P. ix, note. 



