other parts were painted a bright vermilion.

Figure 3 explains one way of connecting levers, and their uses as a
mechanical aid. The base is four by fifteen inches in size, and the
pillars are respectively six and ten inches in height, and are firmly
mortised and glued into the base. The upper lever is eighteen inches in
length, and connects with the ten-inch lower lever.

The lead weights, sliding on the narrow edges of the levers, balance
each other, and show how the heavy wagon of coal is balanced in the
office by the weight on the scale-beam.

A wedge made of oak ten inches in height and five inches in width is
indicated by Figure 4.

Figure 5 represents a diminutive pile-driver, twenty-eight inches in
length, showing the plan and action of a large machine.

[Illustration: SIMPLE MECHANICAL APPARATUS MADE BY BOYS UNDER 14 YEARS
OF AGE.

DRAWN BY J. ABDON DONNEGAN.

Fig. 1. FURNACE

Fig. 2. FORGE

Fig. 3. LEVER SCALES

Fig. 4. WEDGE

Fig. 5. PILE DRIVER

Fig. 6. SCREW PRESS

Fig. 7. INCLINED RAILWAY]

The two-pound drop-hammer falls a distance of twenty-two inches in the
grooves of the vertical posts which are mortised and glued into the
base, as are also the oblique braces to which are attached the bobbin,
or axle, and crank, on which the cord is wound that raises the hammer.
This hammer is a flat piece of iron having two pieces of wood, each four
by two and one-half inches in size, cemented to it. A wire hook is
attached just above, and the extended arm of the hook as the weight
nears the top, meets a projecting pin, and slips the weight from the
cord.

Figure 6 is the model of a wood-press useful in pressing flowers for an
herbarium. The base and pressure board are each ten inches square, the
supports eight inches in height, and a wooden screw connected with the
upper board turns in the cross-piece. This and the models shown in the
drawings numbered 3, 5, and 10 were made by Harry Stoecker.

Figure 7 represents the model of an inclined railway constructed upon
the plan of the inclined railway actually in use between Hoboken and
Jersey City Heights. A board forty-five inches in length and ten inches
in width connects the terminal platforms of this model. The upper
platform rests on a support thirty-three inches in height; to this
support is attached an axle turned by a crank, on which are wound the
reversed cords which connect with the ascending and descending
platforms. These platforms are