an envelope stamp with the head deeply embossed. The
Heligoland stamp like all the stamps of that island is in the local
colors, red, white and green, of which the inhabitants are so proud. In
the case of the Heligoland and Bavaria stamps the entire sheets are
embossed at one time and not each stamp singly, as is usual.

[Illustration]

Some curious varieties of this sort of printing are found among the
early issues of Peru. The machine in use there printed the stamps one
at a time on long strips of paper. When the end of a strip was reached
another was attached to it with gum, in order that the process might be
continuous. It frequently happened that an impression was printed upon
or partly upon the overlapping ends of the strips. In the course of time
these ends became separated and thus we find stamps embossed partly with
and partly without color and occasionally entirely without it.
Philatelists call these varieties semi-albinos and albinos. The latter
term is also applied to envelope stamps which have been embossed without
the die being inked.

Lithography, while a simpler and less expensive mode of making stamps
than those previously described, is not often employed for the purpose.
The work is inferior in quality and too easily counterfeited to commend
itself. In lithography the lines of the design are neither sunken nor,
to any appreciable extent, raised above the surface. The design is
practically a drawing, in a certain greasy ink, upon stone of a
particular quality. When several colors are used, as in
chromo-lithography, a separate stone is prepared for each. The design is
sometimes drawn directly on the stone and at others transferred to it.
For stamps a die is made in wood, metal or stone. Impressions from this
are made in transfer ink (a very "fat" ink, made of soap, resin, tallow,
etc.) upon transfer paper. These impressions are placed, face downward,
on the stone and the paper is moistened. On being passed through a press
the ink adheres to the stone and the paper is easily removed. A wet
sponge is passed over the stone, the water adhering to the exposed
surface but not to the greasy ink. While it is moist a roller, covered
with transfer ink, is rolled over the designs to which it adheres. The
wetting and rolling are alternated until the designs have sufficient
body. Lastly, a very weak solution of nitric acid, gum arabic and water
is passed over the stone. This is at once washed off. It bites the ston