and carried to the conductor E. The rubber is fastened to a glass pillar, G, and the conductor E stands likewise on glass, the cylinder L M is also insulated, therefore before the machine can be worked with effect, a chain must be hung on the rubber to communicate with the table, and by means of the table with the earth. By this chain the electricity is collected, for the rubber having parted with all it has, is supplied from the ground.

If an ostrich's feather be placed in the hole x of the conductor E, and the machine worked, the parts of the feather will endeavour to avoid each other, and stand erect, because the several filaments being electrified with the same electricity repel each other. The electrical bells, fig; 2, shew the manner in which electricity is communicated. The two outer bells zz are suspended on chains, the middle one is insulated or hung on a silken thread: the two small brass balls a a are likewise insulated. If the apparatus be hung on the conductor E, and the machine worked, the bells zz will become electrified or have more than their natural share of electricity, and will attract the balls a a, which will receive from the bells a part of their superabundant electricity, and will carry it to the bell r, this by means of the chain conveys it to the earth, the great repository of electricity: hence so long as the machine is worked the bells will keep ringing. If an apparatus of this kind be connected with a conductor on the outside of a building, it will serve to give notice of the approach and passage of any strongly electrified cloud.

Electricity may be communicated to the whole surface of any glass, or to any given part of it,

if that part be covered with a metallic surface, as tinfoil. This is called coating the glass. A glass jar, fig. 3, coated about three fourths over, leaving the upper rim two or three inches deep quite free from coating, is called a Leyden-jar, so named from the town at which it was first made. If the knob r be brought near the conductor E while the machine is working, it will be charged, provided the jar is held in the hand, or stands on a table, &c. which communicates with the earth, because the inside will receive from the conductor more than its natural share, but, as no body can contain in the whole, more than a certain quantity, it will throw off as much from the outside as it receives superabundant inside, of course the two sides of the jar will be in different states of electricity, the inside plus, and the outside minus, and the glass rim being a non-conductor, the electric fluid cannot of itself pass from the inside to the outside, but if the discharging rod, fig. 4, be brought to the jar, so that the knob r shall touch the outside coating, and the knob z touch the wire that communicates with the inside of the jar, then, in an instant, the extra fluid of the inside, will pass through the wire z mato the outside, and the equilibrium will be restored. If instead of the discharging rod, a person touch the outside coating with one hand, and bring the knuckle of a finger of the other hand to the wire a, which communicates with the inside, his body becomes the discharger, and he will feel a shock, which will be more or less severe, as the phial is more or less charged. Any number of persons may receive the shock if they all hold hands, and the person at one extremity touch the outside of the

.

jar while the person at the other extremity touch the wire r of the jar.

Several Leyden jars connected together, Fig. 5, by making a communication between all the outsides, and another between all the insides, form an electrical battery. By means of this, if gunpowder, -gold leaf, or any other inflammable substance be laid on the glass plate a x, and an electrical charge be sent through them, they will instantly take fire. Slender wire may be made red hot, and small animals killed with the electrical battery.

Fig. 6. is an electrometer intended to measure the degree to which any jar, or battery is charged, for if the wire a be unscrewed from the stand, and be fixed at r on the conductor, or a of the Leydenjar, or at F in the battery, when they are charged or charging, then in proportion to the quantity of electricity thrown in, the index u will make a smaller or greater angle with the pillar b u.

It is now ascertained that lightning and electricity are the same; that is, lightning is the rapid motion of vast masses of the electric matter, and thunder is the noise produced by the motion of lightning. Metallic points silently attract electricity from the bodies charged with it, hence the use of pointed conductors to secure buildings from the effects of lightning. The Aurora Boreales, or northern lights, are the effects of the electric fluid passing through highly rarefied air.

Earthquakes, whirlwinds, and water-spouts are generally accompanied with, and dependant upon electrical phenomena. There are three kinds of fish that possess the power of giving the electrical shock similar to that which is experienced from the Ley