Improvements in Graphophone Blanks or Tablets, and in the Manufacture thereof.
Year: 1898

page_text: Date of Application, 7th Nov., 1898-Accepted, 20th May, 1899
COMPLETE SPECIFICATION.
Improvements in Graphophone Blanks or Tablets, and in the
Manufacture thereof.
I, JAMES YATE JOHNSON, of 47, Lincoln's Inn Fields, in the County of London,
Gentleman, do hereby declare the nature of this invention (which has been com-
municated to me from abroad by the American Graphophone Company, a Cor-
poration of West Virginia, having its principal office at 919, Pennsylvania Avenue,
Washington, D.C., in the United States of America) and in what manner the same
is to be performed to be particularly described and ascertained in and by the
following statement: ―
This invention relates to the manufacture of blanks or tablets upon which sound
records may be cut or engraved, and more particularly to the process of treating the
composition of matter of which the tablet is composed to the end that the same
may be perfectly amorphous free from all fibrous or other organic impurities and
without tendency to crystillization.
The method now universally employed in forming a sound record consists in
cutting or engraving an undulatory groove in the surface of a suitable tablet by
means of a cutting style attached to a vibratory diaphragm upon which the
sounds to be recorded are allowed to impinge. The force of the sound waves is
very weak and it is essential to the accomplishment of the best results that the
surface of the tablet should be such as to enable the style to cut a smooth undulatory
line whose undulations shall correspond exactly to those of the recorded sound-
waves. If there is any crystalline formation or any tendency thereto, in the
surface of the material composing the tablet the style is liable to be diverted by
the line of cleavage of the crystal, thus offering variable resistance to the action of
the style and producing irregularities in the groove which do not correspond
exactly to the undulations of the recorded sound waves. It is also very important
that the composition of matter composing the tablet should be free from all fibrous
or other organic matter, as such matters offer uneven resistance to the cutting
action of the style, causing it to form a rough and inaccurate record. In some
cases the style rides over the fibre and makes no record at all, causing what is
known as "blind spots" in other cases the style fails to cut the fibre, but pulls it
out bodily leaving a hole or depression where there should have been a smooth cut;
again the style instead of cutting the fibre or removing it bodily tears through it,
leaving rough jagged ends which, when the rubbing style of a reproducer rubs
over them, give a rough harsh quality to the reproduced sound.
Moreover the organic matter is liable to ferment and mildew thereby greatly
lessening the value of the blank and destroying the record cut therein.
It has been found that in the manufacture of tablets there is often a tendency to
form crystals upon the surface of the blanks, which tendency is due to the presence
in the blank of the "water of crystallization." It has also been found that such
tablets sometime contain fibrous or other organic impurities, such as fine dust
particles, which are at all times floating in the air, and which the most vigilant
care could not entirely exclude.

page_text: The object of the present invention is to produce a blank or tablet which shall
be without any tendency to crystillization and in which all fibrous or other organic
matter shall be destroyed,, and to this end the invention consists in subjecting the
composition of matter which is to constitute the tablet to a degree of heat
sufficient to entirely drive off all "water of crystallization" and entirely destroy
all fibrous and other organic impurities, in the composition of matter.
Heretofore, in the treatment of the composition of matter of which the tablets
were to be formed, heat has been resorted to for the purpose of eliminating the
water, but great care has been taken not to exceed a temperature of about 330
degrees Fahrenheit for fear of "charring" the composition and thereby rendering
it unfit for use as a tablet material. This temperature was not sufficient to
entirely eliminate the water of crystallization and would not destroy fibrous and
other organic matter. My correspondents have discovered, however, that the com-
position of matter may be advantageously subjected to a heat of from 450 to 475
degrees Fahrenheit, and that by so doing the water of crystallization" may be
entirely eliminated and the fibrous and other organic matter be absolutely destroyed.
For the purpose of illustrating this invention the following process may be
given as an example.
five
"
To four hundred and eight pounds of stearic acid, free from oleic
acid and glycerine, seven pounds of aluminic hydrate and eighty
pounds of caustic soda ye, (or such quantity as will produce
partial saponification), add for the purpose of tempering" seventy two
pounds of paraffin, ozokerite or similar material. The caustic soda is incorporated
in water until a lye of 375° Baume is obtained, and this is heated to its boiling
point about 242 degrees Fahrenheit.
The aluminic hydrate is added and is quickly taken up by the lye. The stearic
acid is melted and raised to about the same temperature and the compound of
Iye and aluminium slowly added thereto. It will unite readily therewith. It
is preferred to employ about the temperature indicated, as thereby the formation
of the composition proceeds gradually and without violent ebullition. The tem-
perature of the molten mass is then raised to a point somewhere between 450 and
475 degrees Fahrenheit. When the desired temperature has been reached, the said
temperature is allowed to fall about 100 degrees and then the mass is poured into
the moulds in the usual manner. The reduction of the temperature may be con-
veniently secured by putting out the fire and allowing the mass to stand before
filling the moulds.
It is not essential that all the ingredients constituting the compound material
should first be incorporated in the mixture before heating the same to the high
temperature required to drive off the water of crystallization and destroy all organic
matter, as the ingredients may, if it is found advantageous, lie heated separately
to the degree necessary, or partial combinations may be formed and these be heated
separately to degree required and then the said partial combinations be united to
form the finished compound. It is preferred however, to first incorporate and
thoroughly unite all the ingredients forming the compound and then raise the entire
mass to the high degree of heat herein before described.
The blanks produced not only stand extremes of heat and cold without mildewing
or cracking but they give better results at all times on account of their being
more amorphous and homogeneous than are blanks heretofore made.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed I declare that what I claim is:
1. In the process of making a sound-recording material, the improvement con-
sisting in partially saponifying stearic acid, and then heating the mass to a tem-
perature of about 460° Fahrenheit substantially as described.
2. In the process of making a sound-recording material, the improvement con-
sisting in mixing stearic acid with caustic soda lye, and then heating the mass
to about 460° F.

page_text: 3. The improvement in the process of making sound-recording material which
consists in heating such material to about 460° Fahrenheit, then cooling the same
down to about 360° Fahrenheit, and then moulding the material into the desired
shape, substantially as described.
4. The process of making a sound-recording material consisting in dissolving
aluminium in soda-lye, adding the solution to stearic acid, and raising the tem-
perature of the mass to about 460° Fahrenheit, substantially as described.
5. The process of making a sound-recording material, said process consisting
in adding to stearic acid soda-lye with which a metal, such as aluminium, has been
united, the lye being in such quantity as to produce partial saponification, and
heating the mixture to about 460° Fahrenheit.
6. A composition for receiving engraved records of sounds, comprising saponified
stearic acid admixed with other ingredients as specified, and freed from water of
crystallization and from objectionable impurities by being heated to the described
degree.
Dated this 7th day of November 1898
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C.,
Agents.