IMPROVEMENTS IN THE MANUFACTURE OF ENVELOPES AND WRAPPERS
Year: 1876

page_text: LETTERS PATENT to Jolin Broad, of Hornsey Rise, in the County of Middlesex,
Chemist, and William Brooks Claxton, of George Square, Hoxton, in the County
of Middlesex, Manufacturer, for the Invention of "IMPROVEMENTS IN THE
MANUFACTURE OF ENVELOPES AND WRAPPERS."
Scaled the 30th September 1876, and dated the 4th April 1876.
PROVISIONAL SPECIFICATION left by the said John Broad and William
Brooks Claxton at the Office of the Commissioners of Patents on the 4th April
1876.
JOHN BROAD, of Hornsey Rise, in the County of Middlesex, Chemist, and
WILLIAM BROOKS CLAXTON, of George Square, Hoxton, in the County of Middlesex,
Manufacturer. "IMPROVEMENTS IN THE MANUFACTURE OF ENVELOPES AND
WRAPPERS."
The object of this Invention is protecting the adhesive portions of the envelope,
and for more perfectly securing the fastenings of envelopes and wrappers, rendering
the opening or tampering of them by steam or moisture or any other way very
difficult, if not impossible.
The Invention consists in making the external or internal surfaces corresponding
with the adhesive portions of the envelopes or wrappers waterproof, or in placing
a waterproof substance beneath the adhesive material. The same principle may be
applied in the form of a wafer, the one side of which is adhesive and the other
waterproof, in the usual position of a seal, the wafers being made in various patterns
and colours.
The gums we use in the waterproofing process are those which are insoluble in
water, such as gum copal and similar gums, but one particular gum we cannot
We also use a com-
adhere to, as different papers require different treatment.
position of linseed or other suitable oil and a pigment, the object in all cases being
the same, viz., to make the external side of the adhesive portions of the envelope
or wrapper waterproof. For blue commercial envelopes we use a size before apply-
ing the waterproofing material.
The preparations and waterproofing material can be applied to the surface of the
paper either before the envelope is cut, or afterwards. When the envelopes or
wrappers are made of thick paper we chamfer or bevil off the edges of the paper,
and in some cases reduce the strength of the flap here and there so as to make it
rend or tear readily if force is used.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Broad and William Brooks Claxton in the Great Seal Patent
Office on the 4th October 1876.
JOHN BROAD, of Hornsey Rise, in the County of Middlesex, Chemist, and WILLIAM
BROOKS CLAXTON, of George Square, Hoxton, in the County of Middlesex, Manu-
facturer. "IMPROVEMENTS IN THE MANUFACTURE OF ENVELOPES AND WRAPPERS."
The object of this Invention is protecting the adhesive portions of the envelope,
and for more perfectly securing the fastening of envelopes and wrappers, rendering
the opening or tampering of them by steam or moisture or any other way very
difficult, if not impossible.
The Invention consists in making the external or internal surfaces corresponding
with the adhesive portions of the envelopes or wrappers waterproof, or in placing
a waterproof substance beneath the adhesive material. The same principle may be
applied in the form of a wafer, the one side of which is adhesive and the other
waterproof, in the usual position of a seal, the wafers being made in various patterns
and colours.
The gums we use in the waterproofing are those which are soluble in æther and
alcohol and insoluble in water, such as gum copal and similar gums, but one
particular gum we cannot adhere to, as different papers require different treatment.
We also use a composition of oil and a pigment, the object in all cases being the
same, viz., to make the external surface of the envelope or wrapper waterproof.
For blue commercial envelopes we use a size before applying the waterproofing.
The preparations and waterproofing can be applied to the surface of the paper,
either before the envelope is cut or afterwards, and in some cases the whole of the
back of the envelope is made waterproof. When the envelopes or wrappers are
made of thick paper, we chamfer or bevil off the edges of the flap, and in some cases
reduce the strength of the flap here and there so as to make it rend or tear readily
if force is used.
Having thus described the nature and object of our said Invention, we declare
that what we claim and desire to be secured to us by the herein-before in part
recited Letters Patent is the improvements in the manufacture of envelopes and
wrappers by making the external or internal surfaces corresponding with the
adhesive portions of the envelopes or wrappers waterproof, substantially as herein-
before described.
In witness whereof, I, the said John Broad, on behalf of myself and the said
William Brooks Claxton, have hereunto set my hand and seal, this Third
day of October, in the year of our Lord One thousand eight hundred and
Seventy-six
:
JOHN BROAD. (L.S.)