520 PHYSICAL GEOGRAPHY. 



occurred, conveying the impression of balls of fire to the observer. An instance is given 

 by Mr. Chalmers while on board the Montague, of seventy-four guns, bearing the flag of 

 Admiral Chambers. In the account read to the Royal Society, he states, that "on 

 November 4th, 1749, while taking an observation on the quarter-deck, one of the quarter 

 masters requested him to look to windward, upon which he observed a large ball of blue 

 fire rolling along on the surface of the water, as large as a mill-stone, at about three miles 

 distance. Before they could raise the main tack, the ball had reached within forty yards 

 of the main-chains, when it rose perpendicularly with a fearful explosion, and shattered 

 the main-topmast to pieces." In an account of the fatal effects of lightning in June 1826, 

 on the Malvern Hills, when two ladies were struck dead, it is stated, that the electric 

 discharge appeared as a mass of fire rolling along the hill towards the building in which 

 the party had taken shelter. Sir W. Snow Harris remarks upon the difficulty of explaining 

 these appearances. The amazing rapidity of the ordinary electric spark, and the momentary 

 duration of the light, render it impossible that they should be identical with it ; but he 

 conjectures that there may be a "glow discharge" preceding the main shock, some of the 

 atmospheric particles yielding up their electricity by a gradual process before a discharge 

 of the whole system takes place. In this view, the distinct balls of fire of sensible duration 

 which have been perceived, are produced in a given point or points of a charged system 

 previously to the more general and rapid union of the electrical forces. 



The remarkable electrical meteor called the Mariners' Lights, or St Elmo's Fire, 

 has frequently been observed during storms at sea. Pliny mentions lights noticed 

 by the Roman mariners during tempests, flickering about their vessels, to which Seneca 

 likewise makes allusion. By the superstition of modern times they have been converted 

 into indications of the guardian presence of St. Elmo, the patron saint of the sailor, hence 

 called cuerpo sante by the Spanish mariners. During the second voyage of Columbus 

 among the "VYest India islands, a sudden gust of heavy wind came on in the night, and his 

 crew considered themselves in great peril, until they beheld several of these lambent 

 flames playing about the tops of the masts, and gliding along the rigging, which they 

 hailed as an assurance of their supernatural protector being near. Fernando Columbus 

 records the circumstance in a manner strongly characteristic of the age in which he lived. 

 " On the same Saturday, in the night, was seen St. Elmo, with seven lighted tapers, at the 

 topmast. There was much rain and great thunder. I mean to say that those lights 

 were seen which mariners affirm to be the body of St. Elmo, on beholding which they 

 chanted many litanies and orisons, holding it for certain, that in the tempest in which he 

 appears, no one is in danger." A similar mention is made of this nautical superstition in 

 the voyage of Magellan. There is on such occasions a strong charge of electricity in the 

 air, which becomes visible in the form of pale-coloured flames, as it is gradually relieved. 

 These harmless fires usually appear quivering on the extremities of bodies, as the topmasts 

 and yard-arms of ships, the points of spears and military weapons, with other projecting 

 and exposed objects. In showers of rain and snow, the drops and flakes have been 

 observed to be luminous. 



It is a striking instance of the triumph of mind, that by the introduction of lightning 

 conductors into different civilised states, the power of this most energetic agent of nature 

 is controlled, and comparative security provided for life and property, otherwise in 

 imminent jeopardy, when a severe thunder-storm occurs. Experience has taught the 

 prime importance of furnishing exposed or elevated structures with a conducting apparatus, 

 and has sufficiently shown that the immunity from danger enjoyed by many an unprotected 

 building has been merely accidental ; for when the teeming thunder-cloud has been wafted 

 within reach of the edifice hitherto unscathed, the delusion has vanished, that man may 

 carelessly and with impunity thrust up his handiwork into the region of storms, as if 



