IMPROVEMENTS IN THE MANUFACTURE OF SULPHURATED LEAD, IN Apparatus THEREFOR. AND IN ITS APPLICATION TO VARIOUS USEFUL PURPOSES
Year: 1873

page_text: LETTERS PATENT to James Noad, of Bower Road, Hackney Wick,
in the County of Middlesex, Engineer, for the Invention of
"IMPROVEMENTS IN THE MANUFACTURE OF SULPHURATED LEAD, IN Apparatus
THEREFOR. AND IN ITS APPLICATION TO VARIOUS USEFUL PURPOSES."
Sealed the 8th August 1873, and dated the 13th February 1873.
PROVISIONAL SPECIFICATION left by the said James Noad at the
Office of the Commissioners of Patents, with his Petition; on the
13th February 1873.
I, JAMES NOAD, of Bower Road, Hackney Wick, in the County of
Middlesex, Engineer, do hereby declare the nature of the said - Invention
for "IMPROVEMENTS IN THE MANUFACTURE OF SULPHURATED LEAD, IN Apparatus
THEREFOR, AND IN ITS APPLICATION TO VARIOUS USEFUL PURPOSES," to be as
follows:-
My Invention relates to the manufacture of a compound of sulphur
and lead which possesses very peculiar properties, and is applicable to .
many useful purposes.

page_text: In practising my said Invention I use two pots placed over separate
fires and connected by pipes with a mixing chamber. The latter is to
be provided with an inlet pipe for air or steam, and an outlet pipe
leading to a condensor; it also has a rake or rabble. I melt lead in ono
of the aforesaid pots and sulphur in the other, when the lead is heated
to about 710° Fahrenheit and the sulphur to its melting point I open the
communications, and allow the liquids in the proportion of five parts lead
and one part sulphur to flow into the mixing chamber, which must be
previously warmed to prevent its chilling the lead; afterwards sufficient
heat is generated by the sulphur to keep it hot. While in the mixer the
lead and sulphur are mixed by means of the rabble, air or superheated
steam being freely admitted through the inlet pipe. The vapors of
bisulphide of lead escape through the outlet pipe to the condensor.
When the lead has taken up the sulphur it is expelled through a
suitable opening and a fresh charge is introduced. The lead has by this
treatment been converted into a dark grey brittle powder. Free
admission of air (or steam) and incessant stirring are absolutely essential
to the success of this part of my process. The said powder after being
ground, sifted, bolted, or floated and dried will be ready for use for
various purposes. It will not be necessary for me to name all the purposes
to which it may be applied, but the following are some of the most
important. I make a self conducting composition for electrotyping
purposes by taking one pound of gutta percha, india-rubber, or other
gummy or resinous matter at 200° Fahrenheit and blend with it from
two to twenty-eight pounds of powder, sometimes adding gutta percha oil,
that is to say oil obtained by the destructive distillation of gutta percha.
This composition is passed between hot rollers gauged to the thickness
required; then its surface is rubbed with blacklead applied with a hard
brush, it is then softened by heat and moulded in the usual way by a
screw press. If an adhesive deposit of copper is required it is now
ready for the electrotyping bath, if it is to be used for a non-adhesive
deposit blacklead is again applied to the surface, or it is immersed for
about one-half minute in a bath of sugar of lead, (having been previously
connected by the poles of a galvanic battery), then rinsed gently with
water, and immersed in the copper solution. I add to one pound of
sulphur from two to eight pounds of the aforesaid powder, and melt it,
allowing the gases to escape. This compound forms a hard durable
material for copies of wood blocks, type plaster patterns, and the like.

page_text: It may be substituted for lead for fixing ironwork pipes, and the like, as
it sets up no galvanic action.
For obtaining curved casts from a straight pattern. such as a stereo cast
for a printing cylinder from a flat form I cast the mould in a mixture of
four parts of powder and one part of shellac melted together as above
described; as soon as this mixture has set I remove it from the pattern
and lay it on a suitably curved block pressing it gently till it fits the
same; I then cast in it the mixture of powder and sulphur. The powder
should be calcined at a dull red heat to expel the gases. I also grind the
aforesaid powder in oil or water to form a paint. The said powder being
a sulphide will be a great preservative of metal, it is moreover very
tough and adheres to the metal with remarkable tenacity. The paint
may also be made from the powder and sulphur used for the type. I
also make crucibles by mixing the aforesaid powder with fire-clay and
then burning the same; and I make slabs, tesseræ, letters for advertising
purposes, and other like articles by mixing the compound of the
aforesaid powder and sulphur with sand, whiting, brick dust, or other
like substances, and stamp the letters or other articles therefrom, or I
may colour the powder, blend it with sulphur as above, and pour it into
suitable moulds.