of which wire are bent at right angles, and run into the board.  The plate will consequently turn on this axis as on a hinge.  At the top of the plate, d, a small projection of the tin turns inward, and to this one end of the cord, m m, is attached.  This cord passes back from d to a small pulley at the upper part of the board, and at the lower end of it a tassel, loaded so as to be an exact counterpoise to the card, is attached.  By raising the tassel, the plate will of course fall over forward till it is stopped by the part b striking the board, when it will be in a horizontal position.  On the other hand, by pulling down the tassel, the plate will be raised and drawn upward against the board, so as to present its convex surface, with the words STUDY HOURS upon it, distinctly to the school.  In the drawing it is represented in an inclined position, being not quite drawn up, that the parts might more easily be seen.  At d there is a small projection of the tin upward, which touches the clapper of the bell suspended above every time the plate passes up or down, and thus gives notice of its motions.

[Illustration]

Of course the construction may be varied very much, and it may be more or less expensive, according to the wishes of the teacher.  In the first apparatus of this kind which I used, the plate was simply a card of pasteboard, from which the machine took its name.  This was cut out with a penknife, and, after being covered with marble-paper, a strip of white paper was pasted along the middle with the inscription upon it.  The wire c c, and a similar one at the top of the plate, were passed through a perforation in the pasteboard, and then passed into the board.  Instead of a pulley, the cord, which was a piece of twine, was passed through a little staple made of wire and driven into the board.  The whole was made in one or two recesses in school, with such tools and materials as I could then command.  The bell was a common table bell, with a wire passing through the handle.  The whole was attached to such a piece of pine board as I could get on the occasion.  This coarse contrivance was, for more than a year, the grand regulator of all the movements of the school.

I afterward caused one to be made in a better manner.  The plate was of tin, gilded, the border and the letters of the inscription being black.  A parlor bell-rope was carried over a brass pulley, and then passed downward in a groove made in the mahogany board to which the card was attached.

A little reflection will, however, show the teacher that the form and construction of the apparatus for marking the times of study and of rest may be greatly varied.  The chief point is simply to secure the principle of whispering at definite and limited times, and at those alone.  If such an arrangement is adopted, and carried faithfully into effect, it will be found to relieve the teacher of more than half