Procure a pane of glass about 10 inches in width and 14 in length, and support it between two large books, as shown in Fig. 1.  The glass must be inserted in the books in such a way that it shall be an inch and a fraction above the surface of the table.  Then, with a pair of scissors, cut out of a piece of tissue-paper a number of figures, such as men, women, clowns, frogs, etc.  These little figures must not exceed three-quarters of an inch in length.  We show some of actual size in Fig. 1.  They may be cut out of papers of different colors, so as to give variety to the scene.  After they are prepared they are to be placed in the ball-room, that is to say, in the space between the books, glass, and table.  They should be laid flat upon the table, and alongside of one another.  Now rub the upper surface of the glass vigorously with a piece of silk or woolen, and, in a few instants, the figures will be attracted by the electricity, and suddenly stand up straight and jump up to the transparent ceiling of their ball-room.  Then they will be repelled, and again attracted, and thus keep up a lively dance.  When the rubbing is stopped, the dance continues spontaneously for some little time, and even the contact of the hand suffices to animate the figures.  In order that this experiment shall prove a success, the glass used must be very dry, as well as the fabric with which it is rubbed.  If the latter be warmed, the manifestation will be more rapid and energetic.  Silk answers better than woolen.

[Illustration:  FIG. 2.—­SILHOUETTE PORTRAITS.]

Silhouette Portraits.—­Take a large sheet of paper, black on one side and white on the other, and affix it to the wall, white surface outward, by means of pins or tacks.  Place a very bright light upon the table, at a proper distance, and allow the person whose portrait it is desired to form to stand between it and the wall (Fig. 2).  Then, with a pencil, draw the outlines of the shadow projected.  While this is being done, it is very necessary that the subject shall keep perfectly immovable.  When the outlines are sketched, remove the paper from the wall and cut out the portrait.  After this, all that remains to be done is to turn the portrait over and paste it to a sheet of white paper.  The silhouette is profiled in black, and if the operation be skillfully performed, the resemblance will be perfect.—­La Nature.

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HOW TO BREAK A CORD WITH THE HANDS.

Our readers have often seen grocers’ clerks or employes of business houses break the string with which they had tied up a package, by seizing it with the hands, bringing the latter close together, and then suddenly separating them with a quick movement.  If it be thought that this quick motion is sufficient, let any one try it, and he will merely cut his hands without breaking the string, provided the latter has some little strength.  In order to succeed, the cord must be arranged in a certain manner, as we shall explain.