Part 15 (1/1)

It has not been found, that the electric shock takes up any sensible space of tireatest distances

The electric shock, as also the coh which it passes; and if its passage from conductor to conductor be interrupted by non-conductors of a e, in such a manner as to exhibit the appearance of a sudden expansion of the air about the center of the shock

If the electric circuit be interrupted, the electric e, will pass to any other body that lies near its path, and instantly return This may be called the _lateral explosion_ The effect of this lateral explosion through a brass chain, when the quantity of electricity is very great, will be the discolouring and partial burning of the paper on which it lies

If a great quantity of electricity be accumulated, as in a _battery_, the explosion will pass over the surfaces of i the _concussion_ of the substance Also the electric matter thus accumulated and condensed will, by its repulsion, for the surface of a flat piece of metal on which the explosion is received

If an electric shock, or strong spark, be h, or over, the belly of a muscle, it forces it to contract, as in a convulsion

If a strong shock be sent through a small animal body, it will often deprive it instantly of life

When the electric shock is very strong, it will give polarity to netic needles, and sometimes it reverses their poles

Great shocks, by which animals are killed, are said to hasten putrefaction

Electricity and lightning are in all respects the sa may be imitated by electricity, and every experiht down from the clouds by means of insulated pointed rods of metal

LECTURE xxxVI

_The same Subject continued_

Three curious and i the latest improvements in electricity, deserve a particular explanation, and in all of theeneral principles mentioned above, viz that bodies placed within the influence, or, as it is usually termed, within the atmosphere, of an electrified body, are affected by a contrary electricity, and that these two electricities mutually attract each other These instruments are the _electrophorus_, the _condenser_ of electricity, and the _doubler_ of it

The electrophorus consists of an insulated conducting plate applied to an insulated electric If the latter have any electricity coative, the positive electricity of the former will be attracted by it, and consequently the plate will be capable of receiving electricity fro, in this situation, capable of containing more electricity than its natural quantity Consequently, when it is removed from the lower plate, and the whole of its electricity equally diffused through it, it will appear to have a redundance, and therefore will give a spark to any body co then replaced upon the electric, and touched by any body coain affected as before, and give a spark on being raised; and this processthe place of any other electricalplate of the electrophorus be applied to a piece of dry wood, h which electricity can pass but very slowly, or if the insulated conducting plate be covered with a piece of thin silk, which will e of electricity, and it be then applied to another plate co with the earth; and if, in either of these cases, a body with a large surface possessed of a weak electricity be applied to the conducting plate, the weak electricity not being able to overcome the obstruction presented to it, so as to be communicated to the other plate, will affect it with the contrary electricity, and this reacting on the first plate, will condense its electricity on that part of the plate to which it is contiguous; in consequence of which its capacity of receiving electricity will be increased; so that on the separation of the two plates, that electricity which was before condensed, being equally diffused through the whole plate, will have a greater intensity than it had before, attracting light bodies, or even giving a spark, when the body from which it received its electricity was incapable of it For though it contained a great quantity of electricity, it was diffused through so large a space that its intensity was very small

This instrument is therefore called a _condenser of electricity_

If an insulated plate of ree of electricity be presented very near to another plate co with the earth, it will affect this plate with the opposite electricity; and this being, in the same manner, applied to a third plate, will put it into the same state with the first If then these two plates be joined, and the first plate be presented to either of the attracted by that of the plate presented, that of the other will be drawn into it, so that its quantity will be doubled The saain double the electricity of this plate, till, fro quite insensible to the most exquisite electroive sparks This instrument is therefore called a _doubler of electricity_, of excellent use in ascertaining the quality of atmospherical electricity when ever so small If this instrument be so constructed that these three plates can be successively presented to one another by the revolution of one of the doubler_; and in this form it is most convenient for use

THE END