a dry rat may. 4. Lightning burns: fo does elec tricity. Dr. Franklin fays, that he could kindle with it hard dry rofin, fpirits unwarmed, and even wood. 5. Lightning fometimes diffolves metals: fo does electricity. 6. Lightning has often been known to strike people blind. And a pigeon, after a violent fhock of electricity, by which the Doctor intended to have killed it, was observed to have been ftruck blind. 7. Lightning destroys animal life. Animals have likewife been killed by the fhock of electricity. The largest animals, which Dr. Franklin and his friends had been able to kill, were a hen, and a turkey which weighed about ten pounds.

To demonftrate, in the clearest manner poffible, the fameness of electrical fire with the matter of lightning, Dr. Franklin, aftonishing as it muft have appeared, contrived actually to bring lightning from the heavens, by means of an electrical kite, which he raised, when a ftorm of thunder was perceived to be coming on.

This kite had a pointed wire fixed upon it, by which it drew the lightning from the clouds. The lightning defcended along the hempen string that held the kite and was received by a key tied to the extremity of it. That part of the string, which

the

the Doctor held in his hand, was of filk, that the electric fire might ftop at the key, and not reach his body.

He found, that the ftring would conduct electricity even when nearly dry, but that, when it was wet, it would conduct it quite freely; fo that it would ftream out plentifully from the key, at the approach of a person's finger. At this key he charged phials, and from electric fire thus obtained, he kindled spirits, and performed all the common electrical experiments.

This discovery, of the sameness of lightning and electricity, was applied by Dr. Franklin to a moft useful purpose; namely, to the securing buildings from the dreadful effects of lightning in a thunder ftorm. With regard to thunder itself, or the found or noise we hear, it is perfectly harmless. It is the lightning that does the mifchief.

He effected this, by fixing a pointed iron rod higher than any part of the building, and joining to the lower end of it a wire, which communicated with the earth. This rod the lightning was fure to feize upon, in preference to any other part of the building, and defcended along it and the wire

* Some bodies conduct the electric fire, and fome do not conduct it. Silk is of the latter kind. P 6

till

till it reached the earth, where it was inftantly diffipated without doing any harm.

All public buildings, and especially all magazines, ought to have fuch an apparatus for defend- · ing them from lightning; and many, I believe,

have.

The fire of electricity is very different from common fire, and operates in a very different manner. It has been known to melt a fword in the fcabbard, without injuring the scabbard itself; and to melt money in a man's pocket without burning his clothes. In a word, it feems to be of fuch a nature, that it can easily penetrate through porous bodies without affecting them, and spends all its force upon those that are hard and folid.

The experiment of drawing lightning from heaven, by means of an electric kite, is attended with danger. It proved fatal to Abbé Richman, who, in 1753, was killed by a flash of lightning, which he drew from the clouds, in an experiment he was making at Petersburgh.

Electricity has been applied to some medical purpofes, with fo much fuccefs, that it may now be confidered as part of the fcience.

CHAP.

CHA P. CXXXIII.

ON THE SOUND OF THUNDER, AND THUNDER

BOLTS.

HE reafon, why we do not hear the dreadful

THE

noise of the thunder, as foon as we fee the lightning, is, because found is longer in arriving to our ears, than light to our fight.

Sound

Light moves almost instantaneously. moves no more than 1142 feet in a fecond. That light moves much faster than found, any one may fatisfy himself by observing a gun discharged at a distance; for he will fee the fire long before he hears the found.

The continuation and repetition of the found is caused by a kind of echo formed in the clouds, to which many hard bodies upon the earth may contribute, which return those rollings we hear after a great clap of thunder.

A thunder bolt is nothing but a more solid and moft rapid flame, which, with incredible swiftness flies from the clouds to the earth, and through every thing standing in its way, being interrupted by nothing. It fometimes kills men and animals, burns and overthrows large trees and buildings, and fets fire to every thing in its way.

СНАР.

CHA P. CXXXIV.

OF WATER-SPOUTS, WHIRLWINDS AND Hur

RICANES.

SIGNIOR Beccaria, of Turin, thinks that elec tricity is the cause of water-spouts. To make this more evident, he firft defcribes the circumstances attending the appearance of these spouts ; which are as follow.

They generally appear in calm weather. The fea feems to boil, and fend up a fmoke under them, rifing into a hill towards the fpout. At the fame time, perfons who have been near them have heard a rumbling noise.

The bape of a water-fpout is that of a speaking trumpet, the wider end being in the clouds, and the narrower end towards the fea.

The fize is various, even in the fame fpout. The colour is fometimes inclining to white, and fometimes to black. Their pofition is fometimes perpendicular to the fea, fometimes oblique, and fometimes the fpout itself is in the form of a curve. Their continuance is very various, fome disappearing as foon as formed, and fome continuing a con

fiderable