Mr. C. Tomlinson on some Effects of Lightning. 121 



to an optical illusion. We need not discuss his objections, 

 seeing how numerous the cases are, and, apparently, well 

 established. Let us take only one or two cases. Mr. Chalmers 

 states (' Phil. Trans.' xlvi.) that, being on board the ' Mon- 

 tague ' (seventy-four guns) on November 4th, 1749, he 

 observed a large ball of blue fire rolling along on the surface 

 of the water, as big as a millstone, at about three miles dis- 

 tant. 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 in pieces. So also on the Malvern Hills, in 

 June 182 G, a ball of fire was observed to roll along the hill 

 towards a building where some people had taken shelter. 

 Here it exploded, and killed two of them. 



According to Snow Harris these luminous balls result 

 from a kind of brush, or glow-discharge. In the case of the 

 1 Montague/ it was rolling on the surface of the water 

 towards the ship from to windward. This was evidently a 

 sort of glow-discharge, or St. Elmo's fire, produced by some 

 of the polarized atmospheric particles yielding up their elec- 

 tricity to the surface of the water. On nearing the ship the 

 point of discharge became transferred to the head of the 

 mast ; and the striking distance being thus diminished, the 

 whole system returned to its normal state, that is to say, a 

 disruptive discharge ensued between the sea and the clouds, 

 producing the usual phenomena of thunder and lightning, 

 termed by the observers " the rising of the ball through the 

 mast of the ship." The case on the Malvern Hills is another 

 instance of the same kind. 



Arago is particularly sceptical as to the appearance of 

 globular lightning within the walls of a building, but he 

 quotes a case related by Maffei, which occurred in September 

 17 lo, in the territory of Massa-Canara, in Italy. He took 

 refuge from a storm in a chateau, where he was received by 

 the mistress of the house in a room on the ground floor. 

 Suddenly they saw a bluish-white flame rise from the floor, 

 agitated, but with no progressive motion. After gradually 

 acquiring a considerable volume it suddenly disappeared. 

 Maffei felt in his shoulder, proceeding from his back upwards, 

 a peculiar tickling sensation (un cltatoidllement particulier) , 

 plaster detached from the ceiling fell upon his head, and an 

 explosion occurred, which did not resemble the sound of 

 thunder. 



A case is recorded in Mr. Symons's Meteorological Maga- 

 zine for 1883, as having occurred on July 28th, about G p.m., 

 in the printing-office of Mr. Hurt, Mount Washington, New 



