CRAYONS, PENCILS, AND WRITING CHALK."
Year: 1881

page_text: 46
LETTERS PATENT to William Cullen Horne, of Sunningdale, Parkhurst Road,
Bexley, in the County of Kent, for an Invention of
CRAYONS, PENCILS, AND WRITING CHALK."
IMPROVEMENTS IN
PROVISIONAL SPECIFICATION left by the said William Cullen Horne at
the Office of the Commissioners of Patents on the 25th February 1881.
WILLIAM CULLEN HORNE, of Sunningdale, Parkhurst Road, Bexley, in the
County of Kent. "IMPROVEMENTS IN CRAYONS, PENCILS, AND WRITING CHALK."
According to this Invention phosphorescent substances are used in the
manufacture or preparation of crayons, pencils, and writing chalks, which are
thereby made to produce luminous marks (that is to say), marks which on exposure
to light will absorb light, and thereafter in the dark will emit light, so as to be
visible. For this purpose I incorporate with the materials of which crayon or
pencil is to be made, or with writing chalk, a phosphorescent substance or
substances such as will after exposure to light remain phosphorescent some hours.
The phosphorescent substance so used may be luminous powders such as is used in
the manufacture of luminous paint according to the Invention for which Letters
Patent, No. 4152, dated 7th November 1877, were granted to the late
W. H. Balmain, or such as can be purchased of W. Puzey, of 5, Aldermanbury
Postern, in the City of London, but I do not restrict myself to these substances.
According to another modification, crayons or pencils may be made of phosphor-
escent substance or substances in the form of powder mixed with a vehicle to hold
the same together. Such vehicle may be in the form of a jelly and variously
composed. A sufficient quantity of the vehicle is worked into a paste with the
phosphorescent substance or substances. Also with the phosphorescent substance
there may be mixed a proportion of pipe clay. The phosphorescent powder, having
been worked into a paste with the vehicle, is rolled into slabs or sticks and baked
in a slow oven or otherwise dried.

page_text: A vehicle having an oleaginous base may be used to mix with the phosphorescent
substances so as to form a waterproof luminous crayon or pencil.
It will be evident crayons, pencils, and writing chalk, manufactured according to
my Invention, are applicable to a variety of useful purposes, among which, as
examples, I may mention writing numbers and words on railway trucks, casks, and
packages, especially those that contain inflammable or explosive goods, and which
on that account cannot safely be manipulated by the aid of ordinary artificial
light; writing the addresses of parcels, and also for military and naval purposes;
for the production of land marks visible during the night; for defining the positions
of dangerous obstacles, such as the scaffold poles of buildings in course of erection,
and many other purposes.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Cullen Horne in the Great Seal Patent Office on the
25th August 1881.
WILLIAM CULLEN HORNE, of Sunningdale, Parkhurst Road, Bexley, in the
County of Kent. "IMPROVEMENTS IN CRAYONS, PENCILS, AND WRITING CHALK."
According to this Invention phosphorescent substances are used in the
manufacture or preparation of crayons, pencils, and writing chalk, which are
thereby made to produce luminous marks (that is to say), marks which, after
exposure to light, will emit light, so as to be visible in a dark place. For this purpose
I incorporate with the materials of which crayon or pencil is to be made, or with
writing chalk, a phosphorescent substance or substances such as will after exposure
to light remain phosphorescent some hours. The phosphorescent substance so used
may be luminous powder such as is used in the manufacture of luminous paint
according to the Invention for which Letters Patent, No. 4152, dated 7th November
1877, were granted to the late W. H. Balmain, or such as can be purchased of
W. Puzey, of 5, Aldermanbury Postern, in the City of London, but I do not restrict
myself to these substances. According to another modification, crayons or pencils
may be made of phosphorescent substance or substances in the form of powder
mixed with a vehicle to hold the same together. Such vehicle may be in the form
of a jelly and variously composed. A sufficient quantity of the vehicle is worked
into a paste with the phosphorescent substance or substances. Also with the
phosphorescent substance there may be mixed a proportion of pipeclay. The
phosphorescent powder having been worked into a paste with the vehicle is rolled
into slabs or sticks and baked in a slow oven or otherwise dried.
A vehicle having an oleaginous base may be used to mix with the phosphorescent
substances, so as to form a waterproof luminous crayon or pencil. The phosphor-
escent substance that I prefer to use in carrying out my Invention is known as
sulphide of calcium, and is made by W. Puzey, of 5, Aldermanbury Postern, in the
City of London, and is sold by him or his agents. This particular make of
sulphide of calcium has a phosporescence that continues for many hours in the
dark, after exposure to daylight, and is therefore of a useful luminosity. In
carrying out my Invention I place the phosphorescent substance in water for
24 hours, that the lime of which it is chiefly composed may slack, then stirring the
water that holds the same I await a short interval, so as to allow the coarser
particles to subside before pouring off the supernatant water, still turbid, into
another vessel in which I allow the suspended powder time so settle. This deposit
or precipitate may be dried in moulds and so formed into lumps or pencils of
luminous writing chalk, or I may dry the product of elutriating the sulphide of
calcium and grind it into a fine powder. I take of such powder 60 parts, of finely
powdered pipe clay 10 parts, of curd soap 10 parts, of gum arabic 2 parts, and by
boiling the said ingredients in water intimately mingle the same. When the water
has evaporated sufficiently to leave a paste, the same can be moulded or rolled into
shape and dried in the manner of ordinary crayons.
According to another method of carrying out my Invention, I take spermacetti
and make it into an emulsion with boiling water, into which I then stir the
luminous or phosphorescent powder until a thick paste is formed, which can be
moulded and dried into shape. I also find that rice water, sweet ale, white wax,
Russian tallow, and sugar candy, are useful materials or vehicles to carry or to hold
the luminous powder together so that it can be moulded into shapes suitable to
write with, either alone or protected in the groove or tube of a pencil holder.
It will be evident crayons, pencils, and writing chalk, manufactured according to

page_text: my Invention are applicable to a variety of useful purposes, among which, as
examples, I may mention writing numbers and words on railway trucks, casks, and
packages, especially those that contain inflammable or explosive goods, and which
on that account cannot safely be manipulated by the aid of ordinary artificial light,
writing the addresses of parcels, and also for military and naval purposes, for the
production of landmarks visible during the night, for defining the positions of
dangerous obstacles, such as the scaffold poles of buildings in course of erection, and
many other purposes.
Having now particularly described the nature of my said Invention, and the
manner in which the same is to be or may be performed or carried into effect, I
would have it understood that what I consider to be novel and original and
useful, and therefore claim as the Invention secured to me by the hereinbefore in
part recited Letters Patent is,-
The manufacture of luminous crayons, pencils, and writing chalk, substantially
as hereinbefore described.
In witness whereof, I, the said William Cullen Horne, have hereunto set my
hand and seal, this Twenty second day of August, in the year of our
Lord One thousand eight hundred and eighty one.