LIGHTNING. 



allowed, that lightning- is really an elec- 

 trical explosion or phenomenon. Philoso- 

 phers had not proceeded far in their ex- 

 periments and inquiries on this subject, 

 before they perceivedthe obvious analogy 

 between lightning and electricity, and 

 they produced many arguments to evince 

 their similarity. Hut the method of prov- 

 ing this hypothesis, beyond a doubt, was 

 first proposed by Dr. Franklin, who, 

 about the close of the year 1749, con- 

 ceived the practicability of drawing light- 

 ning down from the clouds. Various cir- 

 cumstances of resemblance between light- 

 ning and electricity were remarked by 

 this philosopher, and have been abun- 

 dantly confirmed by later discoveries, 

 such as the following : Flashes of light- 

 ning are usually seen crooked and waving 

 in the air; so the electric spark drawn 

 from an irregular body at some distance, 

 and when it is drawn by an irregular body, 

 or through a space in which the best con- 

 ductors are disposed in an irregular man- 

 ner, always exhibits the same appearance. 

 Lightning strikes the highest and most 

 pointed objects in its course, in prefe- 

 rence to others, as hills, trees, spires, 

 masts of ships, &.c. so all pointed conduc- 

 tors receive and throw off the electric 

 fluid more readily than those that are 

 terminated by flat surfaces. Lightning is 

 observed to take and follow the readiest 

 and best conductor ; and the same is the 

 case with electricity in the discharge of 

 the Leyden phial : from whence the Doc- 

 tor infers, that in a thunder-storm it 

 would be safer to have one's clothes wet 

 than dry. Lightning burns, dissolves 

 metals, rends some bodies, sometimes 

 strikes persons blind, destroys animal 

 life, deprives magnets of their virtue, or 

 reverses their poles; and all these are 

 well-known properties of electricity. 



To demonstrate, however, by actual 

 experiment, the identity of the electric 

 fluid with the matter of lightning, Dr. 

 Franklin contrived to bring lightning 

 from the heavens by means of a paper 

 kite, properly fitted up for the purpose, 

 with a long fine wire string, and called an 

 electrical kite, which he raised when a 

 thunder storm was perceived to be com- 

 ing on : and with the electricity thus ob- 

 tained, he charged phials, kindled spirits, 

 and performed all other such electrical 

 experiments as are usually exhibited by 

 an excited glass globe or cylinder. This 

 happened in June, 1752, a month after 

 the electricians in France, in pursuance 

 of the method which he had before pro- 

 posed, had verified the same theory, but 

 without any knowledge of what they had 



done. The most active of these were 

 Messrs. Dalibard and Delor, followed by 

 M. Maze;\s, and M. Monnier. 



Nor had the English philosophers been 

 inattentive to this subject. Mr. Canton, 

 however, succeeded in July, 1752 ; and 

 in the following month Dr. Bevis and Mr. 

 Wilson observed nearly the same appear- 

 ances as Mr. Canton had done before. By 

 a number of experiments Mr. Canton also 

 soon after observed, that some clouds 

 were in a positive, while some were in a 

 negative state of electricity : and that the 

 electricity of his conductor would some- 

 times change from one state to the other 

 five or six times in less than half an hour. 



How it happens that particular parts of 

 the earth, or the clouds, come into the op- 

 posite states of positive and negative elec- 

 tricity, is a question not absolutely deter- 

 mined : though it is easy to conceive that 

 when particular clouds, or different parts 

 of the earth, possess opposite electricities, 

 a discharge will take place within a cer- 

 tain distance ; or the one will strike into 

 the other, and in the discharge a flash of 

 lightning will be seen. Mr. Canton 

 queries whether the clouds do not be- 

 come possessed of electricity by the 

 gradual heating and cooling of the air ; 

 and whether air suddenly rarefied may 

 not give electric fire to clouds, and va- 

 pours passing through it, and air suddenly 

 condensed receive electric fire from them. 

 Mr. Wilcke supposes, that the air con- 

 tracts its electricity in the same manner 

 that sulphur and other substances do, 

 when they are heated and cooled in con- 

 tact with various bodies. Thus, the air 

 being heated or cooled near the earth, 

 gives electricity to the earth, or receives 

 it from it ; and the electrified air being 

 conveyed upwards by various means, 

 communicates its electricity to the clouds. 

 Others have queried, whether, since 

 thunder commonly happens in a sultry 

 state of the air, when it seems charged 

 with sulphureous vapours, the electric 

 matter then in the clouds may not be 

 generated by the fermentation of sul- 

 phureous vapours with mineral or acid 

 vapours in the air. With regard to places 

 of safety in times of thunder and light- 

 ning, Dr. Franklin's advice is, to sit in the 

 middle of a room, provided it be not un- 

 der a metal lustre suspended by a chain, 

 sitting on one chair, and laying the feet 

 on another. It is still better, he says, to 

 bring two or three mattresses, or beds, 

 into the middle of the room, and folding 

 them double, to place the chairs upon 

 them ; for as they are not so good con- 

 ductors as the walls, the lightning will 



