ately cool. The boxes soon become more or less distorted,
and then even the best of lifting devices will not remove a hot
pot without several minutes labor in front of the doors.

In Fig. 107 is shown a method of arranging a shield on one type of
charging and removing truck. This shield cannot afford more than
a partial protection to the body of the furnace tender, because
he must be able to see around it, and in some cases even push it
partly through the door of the furnace, but even small as it is it
may still afford some welcome protection. The great advantage in
this case of having the shield on the truck instead of stationary
in front of the furnace, is that it still affords protection as
long as the hot pot is being handled through the shop on its way
to the quenching tank.

It might be interesting to many engaged in the heat-treating or
case hardening of steel parts, to make a special note of the design
of the truck that is illustrated in connection with the shield;
the general form is shown although the actual details for the
construction of such a truck are lacking; these being simple, may be
readily worked out by anyone wishing to build one. This is considered
to be one of the quickest and easiest operated devices for the
removal of this class of work from the furnace. To be sure it may
only be used where the floor of the furnace has been built level
with the floor of the room, but many of the modern furnaces of
this class are so designed.

The pack-hardening pots are cast with legs, from two to three inches
high, to permit the circulation of the hot gases, and so heat more
quickly. Between these legs and under the body of the pot, the two
forward prongs of the truck are pushed, tilting the outer handle
to make these prongs as low as possible. The handle is then lowered
and, as it has a good leverage, the pot is easily raised from the
floor, and the truck and its load rolled out.

HEATING OF MANGANESE STEEL.--Another form of heat-treating furnace
is that which is used for the heating of manganese and other alloy
steels, which after having been brought to the proper heat are drawn
from the furnace into an immediate quenching tank. With manganese
steel in particular, the parts are so fragile and easily damaged
while hot that it is frequent practice to have a sloping platform
immediately in front of the furnace door down which the castings
may slide into a tank below the floor level. Such a furnace with
a q