VOL. Lll.] PHILOSOPHICAL TRANSACTIONS. (^6\ 



pened to the Harriot packet is no more than what often happens to a ship at 

 sea, or to a church, house, or other edifice on land, when the lightning has 

 entered into it, and cannot procure an easy passage out of it. The attempting 

 to procure this easy passage, and thereby avert the mischiefs attending the want 

 of it, is the more particular subject of this communication. 



A few years ago the nature of thunder and lightning, which are both to be 

 considered as different appearances of the same meteor, was very little under- 

 stood. Our predecessors in all ages regarded it as an instrument of Divine ven- 

 geance. They stood too much in awe of it to consider it closely ; and though 

 the Greeks and Romans* were in possession of some observations which might 

 have led them to a more intimate knowledge of it, they were not apprized that 

 what they saw had any relation therewith. It was not, till by experiments and 

 observations on the nature and properties of electricity, and comparing them 

 with the phenomena of thunder and lightning, we were informed that electricity 

 and thunder arose from the same cause; or to speak nearer the truth, were different 

 modifications of the same meteor; that they varied in nothing essential, and only 

 differed in being in degree greater or less. 



The same means^ which taught us the management of one, give us great 

 reason to believe that many of the mischiefs may, by a proper and well disposed 

 apparatus, be prevented of the other. A quantity of electricity, accumulated to 

 a degree sufficient to destroy a large animal, will innocently discharge itself 

 through the smallest wire. And Mr. de Romas in France has found that one of 

 his kites, when flown with a cord composed of hemp and wire, will silently and 

 without any report bring down the matter of thunder from a cloud; though 

 when the apparatus has been altered, and an easy passage has been denied to it, 

 the streams of fire have been seen an inch thick, and 10 feet long, and the re- 

 port has been equal to that of a pistol. It was owing to this easy passage of 

 lightning being interrupted, that occasioned the death of professor Richmann at 

 Petersburg by his own apparatus. 



There is great reason to think, that the mischiefs arising from thunder and 

 lightning happen always near the place where the explosion is made; as those 

 persons who have been present when great mischiefs have been done, universally 

 agree, that when these accidents have happened, the report of the thunder has 

 instantly succeeded the flash of the lightning. As the progress of light is nearly 

 instantaneous, and that of sound somewhat more than 1 100 feet in a second of 

 time, the thunder and lightning happening in the same instant proves the explo- 

 sion to have been very near. We are therefore to guard against the thunder 

 clouds which are near us. The mast of every ship, which is beset on its tops 



* See Plutarch in the life of Lysander, Pliny, Seneca, Caesar, Livy, kc. — Orig. 



