ir guide into a
large room, where they were greeted by a rush of warm air. Here their
guide showed them the method of gumming the stamps and the curious
apparatus used for the purpose. Along the entire length of the room,
with a narrow passage between, are ranged a series of wooden boxes,
quite sixty feet in length. These are heated by steam, and through each
box passes a sort of double endless chain. The sheets are fed, face
down, into this queer machine, and passed under a roller, which allows
the escape of just enough gum to coat the sheet thinly and evenly. The
sheet is now caught on the endless chain by two automatic clamps, and
carried into the long hot-box. It takes only a few moments for the
journey through, but the sheets appear at the other end perfectly dried,
and ready to be trimmed and perforated.

As the method of gumming stamps used by the various bank-note companies
has been a carefully guarded and secret process, the Bureau of Engraving
and Printing has been forced to invent its own machine for this purpose.
The sheets are gummed at the rate of about eighteen a minute, which is
certainly a vast improvement over the old method of putting on the gum
by hand with a brush.

[Illustration: MIXING THE GLUE.]

When the children were weary of watching the funny little brass fingers
move along and hurry the sheets off into the hot-box, they turned to a
corner where a workman was busy over a series of vats and buckets mixing
the gum, which looked very clean and nice, and is made of dextrine, a
vegetable product. The guide now showed them how the gummed sheets are
pressed smooth for perforation, and then led them into a room where a
score or more of odd little machines were in swift operation. Each
machine is tended by two workwomen, most of whom wear fantastic caps of
paper to shade their eyes, as the sheets must be fed into the machines
with absolute accuracy in order that the perforations shall come in the
right place. Each sheet has register lines printed in the margin, which
must be adjusted exactly under a black thread fastened across the
feeding-table. A quick whir of the wheels puts a neat line of pin-holes
lengthwise between the stamps, cutting the sheet in half at the same
time. The next machine perforates the sheet crosswise, and again cuts it
in two, so that the sheets are now divided up into the regulation size
of one hundred stamps each.

The children thought the minute disks of paper punched out