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