IMPROVEMENTS IN LEADS FOR TT Rז
Year: 1882

page_text: LETTERS PATENT to Gustav Daubenspeck of 6 Almner Villas Middlesex
Ink Manufacturer for an invention of IMPROVEMENTS IN LEADS FOR
TT Rזמת
PROVISIONAL SPECIFICATION left by the said Gustav Daubenspeck at
the Office of the Commissioners of Patents on the 26th May 1882.
GUSTAV DAUBENSPECK of 6 Almner Villas Middlesex Ink Manufacturer
IMPROVEMENTS IN LEADS FOR PENCILS"
My present invention relates to improvements in that class of pencils which are
used as substitutes for copying inks, that is to say which may be used as ordinary
pencils, and copies taken from the impressions made by them in the same way as
when copying ink is used I am aware that various substances have already
been used for this purpose but with very little success as for example plumbago,
chalk, gum, chromate of potash, logwood, tannic acid, iron salts, wax, violet of
aniline, etc
Although it has been possible to obtain a coloured press copy from copying
leads, it has never hitherto been possible to obtain a black press copy And it is
the object of my invention to prepare a lead which will give such a copy The
lead which I have invented, and from which a permanent black copy is obtained
is prepared as follows:-
I take 100 parts by weight of nigrosine, 15 parts of phosphine 96 parts of oxide
of Aluminium 12 parts of a soda soap 5 parts of sulphate of copper 17 parts of
hydrochloride of Aniline and 7 parts of chloride of potassium, in each case by
weight; But the proportions of the above materials may be varied within small
limits-I first make a solution of the nigrosine and phosphine with the smallest
possible quantity of water, and I then make a paste by adding to the solution so
obtained the soap and the oxide of Aluminium; To the paste so formed I add the
result of a mixture of the remaining substances, and after thoroughly mixing,
the resulting product is moulded into the shape of pencil leads pressed and dried,
and is then ready for use.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent & of
an Order of the Lord Chancellor filed by the said Gustav Daubenspeck in
the Great Seal Patent Office on the 9th December 1882.
GUSTAV DAUBENSPECK of Almners Villas Stamford Hill in the County of
Middlesex, "IMPROVEMENTS IN LEADS FOR PENCILS"
My present Invention relates to improvements in that class of pencils which are
used as substitutes for copying inks that is to say which may be used as ordinary
pencils, and copies taken from the impressions made by them in the same way as
when copying ink is used I am aware that various substances have already been
used for this purpose but with very little success as for example plumbago,
chalk, gum, chromate of potash logwood, tannic acid, iron salts, wax, violet of
aniline, etc:—
Although it has been possible to obtain a colored press copy from copying leads,
it has never hitherto been possible to obtain a black press copy, and it is the object
of my invention to prepare a lead which will give such a copy.
Since the date of filing my Provisional Specification I have found that while
retaining the principle and essential features of the Invention there described,
better results are obtained from leads which differ slightly in chemical composition
from those given in my Provisional Specification and I now proceed to give those
materials and proportions which I find to be the best-I take 100 parts of
nigrosine, 7 parts of phosphine, 25 parts of graphite 35 parts of Castile Soap,
5 parts of pure aniline in each case by weight-In preparing the leads I firstly
make a solution of the nigrosine and phosphine with the smallest possible quantity
of water which must be warm to dissolve these bodies to this mixture I add the
pure aniline, and then the soap which has been dissolved in warm water-The
resultant mixture is a tolerably stiff warm paste, which must be allowed to cool
and when quite cool I add the 25 parts of graphite to it.-The resultant product
is moulded into the shape of pencil leads, pressed and dried, and is then ready
of use-
Instead of phosphine, flavine may be used or any yellow color produced from
aniline my object for substituting graphite for oxide of aluminium is that I find
a lead is produced which makes a better mark on highly glazed paper, and that
change makes it desirable to have a higher proportion of soap-And I find that
by using pure aniline instead of hydro-chloride of Aniline, a better result is
obtained and the sulphate of copper and the chloride of potassium may then be
dispensed with―
I wish it to be understood that I do not confine myself to the exact details given
above but what I claim is
Firstly. The use of either nigrosine or phosphine, or flavine, in the preparation
of Copying leads :-
Secondly The preparation of Copying leads substantially as described.
In witness whereof I the said Gustav Daubenspeck have hereunto set my
hand and seal this Ninth day of December in the year of our Lord One
thousand eight hundred and eighty two.