Transparent, clear, capable of being seen through.

     Resinous, containing resin, a gummy vegetable juice.

Name a few substances possessing this remarkable property.

Silks of all kinds; the hair and fur of animals, paper, sulphur, and some other minerals; most of the precious stones; the paste of which false gems are made; and many other substances used by us in the common affairs of life, are susceptible of electrical excitement; among domestic animals the cat furnishes a remarkable instance.  When dry and warm, the back of almost any full-grown cat (the darker its color the better) can be excited by rubbing it with the hand in the direction of the hair, a process which is accompanied with a slight snapping noise, and in the dark by flashes of pale blue light.  When a piece of glass is rubbed with silk, or a stick of red sealing-wax with woollen cloth, each substance acquires the property of attracting and repelling feathers, straws, threads of cotton, and other light substances; the substances just mentioned as highly electric are, however, merely specimens.  All objects, without exception, most probably are capable of being electrically excited; but some require more complicated contrivances to produce it than others.

     Electric, having the properties of electricity.

     Susceptible, disposed to admit easily.

     Repelling, the act of driving back.

     Complicated, formed by the union of several parts in one.

Is there not a machine by which we are enabled to obtain large supplies of electric power at pleasure?

Yes; the electrical machine.  It is made of different forms and sizes:  for common purposes those of the simplest form are the best.  A common form of the machine consists of a circular plate of glass, which can be turned about a horizontal axis by means of a suitable handle.  This plate turns between two supports, and near its upper and lower edges are two pairs of cushions, usually made of leather, stuffed with horse-hair and coated with a mixture of zinc, tin, and mercury, called an amalgam.  These cushions are the rubbers for producing friction, and are connected with the earth by means of a metal chain or rod.  Two large hollow cylinders of brass with globular ends, each supported by two glass pillars, constitute the reservoir for receiving the electricity.  They are called the prime conductors, and are supplied with U-shaped rods of metal, furnished with points along their sides, called combs, for the purpose of receiving the electricity from the glass plate, the arms of the U being held upon either side.  The other ends of the conductors are connected by a rod from the middle of which projects another rod terminating in a knob, for delivering the spark.

On turning the plate, a faint snapping sound is heard, and when the room is darkened, a spark is seen to be thrown out from the knob projecting from the prime conductors.