There are few scientific studies more attractive to the general reader than electricity, and few admit of more popular demonstration. The success of the late electrical exhibition in Paris, and its successor in London at the present time, are proofs of the interest taken in this great and mysterious agent whose origin we are in ignorance of, and of whose nature and powers we are daily discovering more and more, and finding there is still an immense field for its application. Some fundamental facts regarding electricity may very easily be studied with the assistance of every-day objects at hand. Amber was the first substance to show attraction when rubbed, but Gilbert found out that glass and sealing-wax, etc., possessed like properties with amber. If we rub a stick of sealing-wax with a piece of cloth, we shall see that it will attract some small fragments of paper placed near it. Nothing is easier than to construct a small pendulum to show with perfect clearness the phenomenon of electric attraction. A piece of iron is fixed on a wooden pedestal, and supports a thread of silk, to the end of which is fastened a little ball cut out of a piece of cork. The stick of sealing-wax after being rubbed with the cloth will attract the ball as shown in fig. 200. [Illustration: Fig. 200.—Sealing-wax attracting a piece of cork.] By means of a piece of paper we can produce a spark. I take a large, strong sheet of drawing paper, heat it very thoroughly, and lay it on a wooden table. I rub it with a perfectly dry hand, or with a piece of woollen material until it adheres to the table. That done, I place a bunch of keys in the centre of the sheet of paper, which I raise, lifting it by two corners. If at this moment any one touches the bunch of keys with his finger, a bright spark will be elicited. The metal is charged with the electricity developed on the paper; if the weather is dry, and the paper thoroughly heated several times, the spark may attain nearly an inch in length. We can easily construct other electrical apparatus. For instance, an “Electrophorus,” or instrument for obtaining electricity by means of induction, or a Leyden jar, can both be made at home. Let us proceed to construct the former, of which we give an illustration (fig. 201). We take a lacquered tea-tray about a foot long, and cut out a sheet of thick wrapping paper, so that it will lie over all the level portion of the tray. At each side of this sheet of paper we fix two bands of paper, as in the illustration (fig. 201), so as to serve as handles. The tea-tray should be placed upon two tumblers to support it and to insulate it, glass being a “non-conductor.” (We will speak of conductors and non-conductors presently.) We have now our Electrophorus made ready for action; let us proceed to see how it will act. [Illustration: Fig. 201—Simple Electrophorus.]