IMPROVEMENTS IN THE TREATMENT OF PAPER AND PARCHMENT, WHEREBY ERASURES FROM WRITINGS THEREON CAN BE DETECTED BY THE EYE
Year: 1879

page_text: LETTERS PATENT to Napoleon Joseph Heckmann, of Loughton, in the County
of Essex, for the Invention of "IMPROVEMENTS IN THE TREATMENT OF PAPER
AND PARCHMENT, WHEREBY ERASURES FROM WRITINGS THEREON CAN BE
DETECTED BY THE EYE."
Sealed the 5th August 1879, and dated the 6th February 1879.
PROVISIONAL SPECIFICATION left by the said Napoleon Joseph Heckmann
at the Office of the Commissioners of Patents on the 6th February 1879.
NAPOLEON JOSEPH HECKMANN, of Loughton, in the County of Essex.
« IM-
PROVEMENTS IN THE TREATMENT OF PAPER AND PARCHMENT, WHEREBY ERASURES
FROM WRITINGS THEREON CAN BE DETECTED BY THE EYE"
The improvements are to be performed by placing in the size (used in the
finishing process of paper making) equal parts of prussiate of potash and sulphuret
of ammonia in the proportion or near thereto of six ounces of each to every gallon
of size. The paper or parchment is to be passed through this solution, and finished
as in making ordinary paper; any color or tint can be added as at present; I prefer
however to use sulphate of manganese and sulphate of copper in proportion of
7 lbs. of the first to 4 lbs. of the latter for the colouring matter with the detective
ingredients first above mentioned, as most attempts at erasure by chemical means
would leave a dark discoloration on paper so treated.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Napoleon Joseph Heckmann in the Great Seal Patent Office on the
5th August 1879.
"
NAPOLEON JOSEPH HECKMANN, of Loughton, in the County of Essex. IM-
=PROVEMENTS IN THE TREATMENT OF PAPER AND PARCHMENT, WHEREBY ERASURES
FROM WRITINGS THEREON CAN BE DETECTED BY THE EYE."
The improvements are performed by placing in in the size (used in the finishing
process of paper making) equal parts of prussiate of potash and sulphuret of
ammonia in the proportions, or near thereto, of six ounces of each to every gallon of
size. The paper or parchment is passed through this solution and finished as in
making ordinary paper; any color or tint can be added as at present; I prefer
however to use sulphate of manganese and sulphate of copper in proportion of
7 lbs. of the first to 4 lbs. of the latter for the coloring matter, added to 30 gallons
of liquid consisting of 3 parts water to one part size, or sufficient size to cause the
paper to float combined with the detective ingredients first above mentioned, as
most attempts at erasure by chemical means would leave a dark discoloration on
paper so treated. Great care is necessary in keeping separate utensils wherein to
dissolve the chemicals, as in no case must the ingredients for the coloring come-in
contact with those chemicals in the first solution, because in that event it would
cause a precipitate which would be on the surface of the paper and not become
embodied therein. It is also imperative that the rolls of the sizing machine
be without eruption or indentation, as the result would be a streak upon the
surface of the paper when passing through the coloring solution. This precaution
is not necessary when the paper is passing through the first solution; therefore to
obviate this discoloration the rolls of the sizer must be coated with at least a half
inch in thickness of vulcanised india rubber. If ordinary metal rolls be used for
the first operation, and they should be free of any eruption or indents on the
surface so as to render them fit for the second or coloring operation, care must be
taken that after the paper has passed through the first solution the rolls and the
size trough be thoroughly cleansed with a solution consisting of one part sulphuric
acid to 8 parts of water, until the discoloration caused by the sulphuret of ammonia
is removed. Should the rolls be covered with vulcanised rubber, it will only be
necessary to use clean water to remove any traces of the first solution before using
the second. It is further necessary that the sizing trough be at least twelve inches
away from the back of the rolls, because if such be not the case the froth caused by
the paper passing through the second solution would attach itself to the paper in
the shape of small globules, and so prevent the second solution from attaching itself
to the already sensitised paper, and thereby causing white spots. The best paper
for use is that known by the term water leaf. The first solution is best formed of
half size and half water of not less temperature than that ordinarily used for sizing
paper, the chemicals previously dissolved separately to be added separately. The
second solution is best formed of three parts water to one part size, or sufficient
size to cause the paper to float on the rolls. In the drying process the temperature
in the drying room must not exceed 80 or 90 degrees Fahrenheit, for if in excess it
renders the paper harsh.
In witness whereof, I, the said Napoleon Joseph Heckmann, have hereunto
set my hand and seal this First day of August Å D 1879.