Improvements in Safety Envelopes.
Year: 1896

page_text: Date of Application, 12th May, 1895-Accepted, 9th Jan., 1897
COMPLETE SPECIFICATION.
Improvements in Safety Envelopes.
I, ROBERT SCHAELLIBAUM, a citizen of the United States, of Lowell, in the State of
Massachusetts, U.S.A., Engineer, do hereby declare the nature of this invention and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
This invention relates to safety envelopes; and the object thereof is to provide an
envelope of this class which having been once sealed cannot be opened by applying
steam, or moisture thereto without leaving evidence of the fact.
My invention is fully disclosed in the following specification, of which the
accompanying drawing forms a part, in which :-
Fig. 1, is a side view of an envelope which is made according to my invention;.
and,
Fig. 2, a similar view with the envelope sealed.
In the drawing forming a part of this specification, I have shown an ordinary
envelope, said envelope being composed of a body portion A, folded ends B, a
folded side C, and a flap D, and the ends, or the sides thereof, adjacent to the flap are
preferably inclined from the corners inwardly toward the center as usual in this class
of devices, and in the practice of my invention, I cover the outer surfaces of said ends.
adjacent to said inclined edges with a black, dark, blue, or other colored ink, or
paint, as shown at E, and I also cover the inner surface of the flap D, adjacent to the.
outer edges thereof with gum as shown at F, and the gummed portion of the flap is
provided with numerous fine perforations G.
When it is desired to seal the envelope, the gummed surface of the flap is moistened
in the usual manner, and said flap is folded over the sealed ends B, and the side (;
and in this operation the paint or ink at E, will not interfere with the sealing of the
envelope.
The paint or ink is composed of a composition which will dissolve when moisture
is applied thereto, and flow through the perforations G, and spread over the outer
surface of the envelope, and will thus show if an attempt has been made to unseal the
envelope, or if the envelope has been unsealed, by applying steam, or moisture
thereto.
This invention is simple in construction and operations, and does not add materially
to the cost of the envelope as usually made, and my invention is not limited to the
coloring material employed, any suitable material being sufficient; and it will also
be apparent that my invention is not limited to the form of the envelope herein
described; and that the same is applicable to any style or form of envelope or wrapper
now made.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. An envelope or other wrapper, which is provided with a flap, the inner surface
of which is gummed, and said Hap being also provided with numerous fine perfora-
tions which are formed in said gunmed portion, and that portion of the envelope or
wrapper to which the flap is adapted to be sealed being provided with suitable coloring

page_text: material, which is adapted to be dissolved by steam or moisture, substantially as shown
and described.
2. An envelope of the usual form, and provided with a flap, the inner surface of
which is gummed, that position of said envelope over which the flap is adapted to be
folded being provided with suitable coloring material or ink, which is adapted to be
dissolved by steam or moisture, and said flap being also provided with fine perforation,
substantially as shown and described.
3. An envelope of the usual form, provided with a body portion, two folded ends
and a folded side, said ends and said side being sealed together, and said envelope
being also provided with a flap which is gummed on its inner surface, and the
perforated ends being provided on their outer surfaces with ink, or other colored
material which is adapted to be dissolved by steam or moisture, substantially as shown
and described.
Dated this 19th day of May 1896.
WHEATLEY & MACKENZIE,
40 Chancery Lane, London, W.C., Agents.