FAIRY KINGS. 31? 



storm passed over the western extremity of London. I was then at 

 Bat terse;;, and made no other remark on tiie phenomena than that 

 the explosions, which were very marked and distinct, were in many 

 instances forked at the lower end, but never at the top; whence it 

 follows, that the clouds were in the positive state for the most part. 

 On the following Sunday, namely the 24th, I happened to he n 

 Kensington Gardens ; in every part of which extensive piece of 

 ground the lightning had left some marks of its agency, chiefly by 

 discoloration of the grass in zipzag streaks, some of which were 

 fifty or *ixty yards in length. Instances of this superficial course of 

 the lightning along the ground, before it enters the earth, are suffi- 

 ciently frequent. But the circumstances which attracted my atten- 

 tion the most was seen in a small grove of trees at the angular point 

 of one of the walks." 



[Journal of Natural Philosophy, Vol. I. p. 546. 



Dr. Darwin is well known to have been one of the chief advocates 

 for this electrical hypothesis. It is thus he adverts to it in his 

 Boianic Garden, Canto I. 1.369: 



So from dark clouds the playful lightning springs, 

 Rives the firm oak, or prints the fairy-rings. 



Upon which he has the following note towards the end of the 

 volume : 



"There is a phenomenon, supposed to be electric, which is yet un- 

 accounted for; I mean the Fairy-rings, as they are called, so often 

 seen on the grass. The numerous flashes of lightning which occur 

 every summer are, I believe, generally discharged upon the earth, 

 and but seldom (if ever) from one cloud to auother. Moist trees 

 are the most frequent conductors of these flashes of lightning, and 

 I am informed by purchasers of wood that innumerable trees are 

 thus crocked and injured. At other times larger parts or promi- 

 nences of clouds gradually sinking as they move alor%. are dis- 

 charged on the moister parts of grassy plains. Now this knob or 

 corner of a cloud, in being attracted by the earth will become nearly 

 cylindrical, as loose wool would do when drawn out into a thread, 

 and will strike the earth with a stream of electricity perhaps two or 

 ten yards in diameter. Now, as a stream of electricity displaces 

 the air it passes through, it is plain no part of the grass can be burnt 



