Hot Substance thereto.
Year: 1888

page_text: Date of Application, 19th May, 1888
Complete Specification Left, 11th Feb., 1889
Complete Specification Accepted, 16th Mar., 1889
Hot Substance thereto.
I GEORGE HENRY QUELCH of 175 Railton Road Herne Hill in the County of Surrey
do hereby declare the nature of this invention to be as follows:-
The object of this invention is to provide a means whereby designs characters or
letters may be invisibly printed written or stamped upon paper which on the applica-
tion of a red hot substance to the said designs characters or letters shall become
visible.
According to this invention 1 stamp or print the design characters or letters in a
saturated solution of Nitrate or Chloride of Potassium in pure water upon common cap
or other suitable paper having an unglazed absorbent surface which if perfumed by
aromatic bark or gums will give out a scent when burning as hereinafter described the
letters or characters forming the design being continuous every word in sentences must
be joined to the preceding and the design carried to a point in the paper having its
position marked by an asterisk or other mark printed visibly, on touching the said
asterisk or mark with a red hot pin, needle wire or other glowing substance the
chemical burns the design through the paper thereby forming the whole design into a
stencil. "Breaks" are provided to prevent the middle portions of the design from
falling out similar to those used in stencils such breaks being arranged so as not to
interfere with the continuity of the design or sentence. The type I find most suitable for
printing with is good soft India rubber type about th of an inch deep. In order to get a
good effect it is necessary to allow free circulation of Air under the design, this may
be done by turning down corners or edges of the paper. After printing upon the
paper should be hot pressed.
1000

page_text: COMPLETE SPECIFICATION.
Printing or Stamping Invisible Designs or Letters on Paper, such
Designs or Letters becoming Visible on the Application of a Red
Hot Substance thereto.
I GEORGE HENRY QUELCH late of 175 Railton Road Herne Hill and now of
51 Branksome Road Brixton in the County of Surrey, Journalist do hereby declare
the nature of my invention and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement :-
The object of this invention is to provide a means whereby designs characters or
letters may be invisibly printed written or stamped upon paper, which, on the
application of a red hot substance to the said designs characters or letters, shall become
visible.
According to this invention, I stamp or print the design characters or letters in a
saturated solution of Nitrate or Chloride of Potassium in water upon common cap or
other suitable paper having an unglazed absorbent surface which if perfumed by
aromatic bark or gums will give out a scent when burning. The letters or characters
forming the design being continuous every word in sentences must be joined to the
preceding, and the design carried to a point in the paper having its position marked
by an asterisk, or other mark printed visably. On touching the said asterisk or mark
with a red hot pin needle wire or other glowing substance the chemical burns the
design through the paper thereby forming the whole design into a stencil. "Breaks"
are provided to prevent the middle portions of the design from falling out similar to
those used in stencils, such breaks being arranged so as not to interfere with the
continuity of the design or sentence.
The type I find most suitable for printing with is good soft India rubber type about
th of an inch deep. In order to get a good effect it is necessary to allow free
circnlation of air under the design. This may be done by turning down corners or
edges of the paper. After being printed the paper should be embossed with any neat
design; the effect of such embossing being to clear away any marks or indentations
which may remain from the process of printing.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:
Printing invisible designs or letters on paper in a saturated solution of Nitrate or
Chlorate of Potassium substantially as described and for the purpose specified.
Dated this 11th day of February 1889
ERNEST SALAMAN,
Agent for the Applicant.