THUNDERBOLTS 155 



masts of ships and the tops of trees, when clouds are low 

 and tension great. It is, in fact, the equivalent in nature 

 of the brush discharge from an electric machine. The 

 Greeks and Romans looked upon this lambent display as a 

 sign of the presence of Castor and Pollux, ' fratres Helenas, 

 lucida sidera,' and held that its appearance was an omen of 

 safety, as everybody who has read the ' Lays of Ancient 

 Rome ' must surely remember. The modern name, St. 

 Elmo's fire, is itself a curiously twisted and perversely 

 Christianised reminiscence of the great twin brethren ; for 

 St. Elmo is merely a corruption of Helena, made mascu- 

 line and canonised by the grateful sailors. It was as 

 Helen's brothers that they best knew the Dioscuri in the 

 good old days of the upper empire ; and when the new 

 religion forbade them any longer to worship those vain 

 heathen deities, they managed to hand over the flames at 

 the masthead to an imaginary St. Elmo, whose protection 

 stood them in just as good stead as that of the original 

 alternate immortals. 



Finally, the effects of lightning itself are sometimes 

 such as to produce upon the mind of an impartial but un- 

 scientific beholder the firm idea that a bodily thunderbolt 

 must necessarily have descended from heaven. In sand or 

 rock, where lightning has struck, it often forms long hol- 

 low tubes, known to the calmly discriminating geological 

 intelligence as fulgurites, and looking for all the world like 

 gigantic drills such as quarrymen make for putting in a 

 blast. They are produced, of course, by the melting of 

 the rock under the terrific heat of the electric spark ; and 

 they grow narrower and narrower as they descend till they 

 finally disappear. But to a casual observer, they irresistibly 

 suggest the notion that a material weapon has struck the 

 ground, and buried itself at the bottom of the hole. The sum- 

 mit of Little Ararat, that weather-beaten and many-fabled 



