the printed sheet. The printer in charge of the
press has the most difficult part of the work, which consists in
polishing the plate with his bare palms after it has been mechanically
inked. This must be done so delicately as to leave neither too much nor
too little ink upon the plate, but only _just enough_ to give a clean,
fine impression.

The presses clattered and clanked, and the children watched with
breathless interest while a great stack of the dampened paper
disappeared rapidly, sheet by sheet, through the press, reappearing
again to be stacked in a second neat pile in the form of thousands upon
thousands of new red two-cent stamps.

Besides the ordinary issues, the young investigators were much
interested in seeing the printing of revenue stamps, of the long-strip
stamps for cigar-boxes, and other tobacco stamps, and particularly the
new two-cent stamps for playing-cards.

Having watched to their entire satisfaction the various movements of the
great presses, the children began to feel that the object of their visit
had been realized, and that there was nothing more to see. They were
therefore somewhat surprised to learn that the _printing_ of the stamps
is merely the beginning of the work upon them, and that a number of very
important things must happen to these small squares of red, blue, brown,
and purple before they are ready to be sold through the little window in
the post-office. After they are printed the sheets must be dried and
pressed out, gummed, dried and pressed again, the sheets perforated and
cut apart, trimmed, and, in addition, carefully counted before and after
each of these operations.

In the early days of postage-stamps, and for several years after they
first came into use, two serious difficulties presented
themselves--_i.e._, the gumming and separating of the stamps. For a time
a thick muddy mucilage was used, which curled up the sheets in a very
inconvenient way. Then, again, before the ingenious device of
perforation was hit upon, it was necessary to cut the stamps apart with
a pair of scissors. Imagine a post-master in these busy days supplying
his customers by the scissors method!

[Illustration: IN THE DRYING-ROOM.]

Fortunately a clever Frenchman conceived the plan of punching a series
of small holes between the stamps, and his invention was promptly
introduced into this country. The children were now eager to see the
finishing processes of stamp-making, and so followed the