Improvements in Recording and Reproducing Sounds, and in Means Applicable therefor.
Year: 1888

page_text: Jate of Application, 1st Sept., 1888
Complete Specification Left, 1st July, 1839-Accepted, 3rd Aug. 1889
Improvements in Recording and Reproducing Sounds, and in Means
Applicable therefor.
I, GEORGE EDWARD GOURAUD, of Little Menlo, Beulah Hill, Upper Norwood, in
the County of Surrey, late Colonel in the United States Army, do hereby declare tho
nature of this invention (a communication to me from abroad by Thomas Alva Edison,
of Llewellyn Park, in the County of Essex and State of New Jersey, one of the
United States of America) to be as follows:-
The first part of this invention relates to methods and apparatus for recording
sound-waves, whether produced by speaking, by music or other sounds, whereby the
recorded sound-waves are given a peculiar form which has been found best adapted
for the clear reproduction of the sounds, and more particularly for the reproduction
of hissing sounds, which latter have not been clearly reproduced by the apparatus and
methods heretofore employed.
All phonographs hitherto made have proved unsatisfactory in consequence of their
lacking clearness and loudness of articulation. This is more particularly due to the
fact that they fail to bring out clearly the hissing sounds, thus making words which
depend upon such sounds for their characteristics generally unintelligible except by
aid of the context.
A microscopical examination of such phonograph-records shows that the recorded
waves are symmetrical in shape, each wave rising and falling on the same gradual
sinuous curve. The waves for the hissing sounds also appear longer and of less depth
and hence more gradual in their rise and fall than those for vowel sounds.
In investigations and experiments which have been carried out with telephonic
apparatus of various kinds, it has been observed that the loudness of the sound
produced in a telephone-receiver by a current impulse is dependent upon the sharp-
ness of the impulse rather than upon its strength. The circuit from a battery of a
hundred cells can be closed through a telephone-receiver without producing sound,
provided the wave is made to have a gradual and uniform rise, a suitable magnet
placed in the circuit serving to taper the wave by its self-induction; while a sharp
impulse from a single cell will produce a noise in the receiver which can be heard for
some distance. Hence it has been concluded that the imperfection of phonograph-
records arises froin the symmetrical and gradual rise and fall of the recorded waves,
and especially of the recorded waves representing hissing sounds, which do not move
the reproducing diaphragm with sufficient abruptness to reproduce the sound waves
with clearness. To overcome this difficulty, the form of the recorded waves is
modified, so that, instead of being a simple sinusoidal symmetrical curve with the
greatest depth at the centre of each recorded wave, the curve is more abrupt at one
end than at the other. This is accomplished by controlling the movement of the
recording point with reference to the relative movement of such point and the
recording surface. Instead of acting perpendicularly to the line of advancing move-
ment, the recording point moves obliquely to such line, so that in one direction the
recording point moves to some extent with the recording surface and in the other
direction the said point moves to some extent against or opposite to the movement of
the recording surface. By regulating these relative movements, it has been found
that the recorded waves can be given the desired abruptness at one end; i.e., the
point of greatest depth of the recorded wave can be transferred from the centre of the
wave to near either end. It is preferable to make this abruptness at the end rather
than at the beginning of each wave, since in the former case the reproducing point
passes down the gradually-declining surface of the wave to its extreme depth and then
rises suddenly at the end of the wave without producing audible disturbances of the

page_text: recorded sound; whilst in the latter case false sounds are produced, which is attributed
to the reproducing point jumping off the abrupt corner of the recorded wave and
striking the bottom of the wave with sufficient force to rebound, making false
vibrations which are audible.
The second part of this invention relates to methods and apparatus for recording
the sound-waves whereby the wave record will be more efficiently produced in
the recording surface.
In recording sounds, a groove is made in the solid material forming the recording
surface by means of an indenting point connected with the diaphragm of the recorder,
and this groove varies in depth accordingly as. the indenting point is advanced or
withdrawn by the vibrations of the diaphragm, thus producing a wave-record from
which the sounds are reproduced, as is well understood.
Heretofore the recording point used has been constructed so that in forming the
groove it removed the material by a scraping action. This was due to the fact that
the advancing edge of the recording style used was perpendicular to the recording
surface or receded from the perpendicular, the result being a scraping rather than a
true cutting of the material. The scraping action has been found to be productive of
false vibrations which become a part of the record, and which are audible as scratching
and other foreign noises when the sounds are reproduced. This difficulty is overcome
by employing a recording point made as a true cutting tool with a cutting edge in
advance of the stock of the tool. It might be supposed that a cutting tool would be
unsuitable for the recording point and that the heel of the tool would strike the bottom
of the groove and prevent the formation of a perfect record or obliterate the record as
made by smoothing or prossing out the indentations more or less; but the movement
of the recording surface is sufficient to keep the heel of the tool clear of the indenta-
tions. The adaptability of the cutting tool form for the recording point is also due
in a measure to the fact that the recording point in a phonograph constructed accord-
ing to this invention is arranged to act more or less obliquely to the recording surface,
so that the recorded waves begin gradually and end abruptly. The recording point
in its forward movement advancing against the movement of the recording surface
enables the cutting tool to clear itself just to the extent that its movement advances
from the perpendicular, and thus the speed of the recording surface will be supple-
mented in respect of serving to keep the heel of the tool clear by the oblique move-
ment of the cutting tool. The waves being abrupt need not be so deep, and hence
there is less difficulty in clearing the tool.
The third part of this invention relates to improvements in phonograph-recorders,
whereby the imperfections arising from the momentum of the moving parts and other
defects in their operation are overcome.
In experimenting with the improved phonograph, it has been discovered that
imperfections are produced in the record made by the machine by reason of the
momentum of the recorder-diaphragm and attached parts, also by reason of lost motion
when the recording point is mounted, as it should be, on a pivoted lever, and also by
reason of the straining of the diaphragm due to the attachment of the recording
point to such diaphragm and to the differences in the directions of movement of the
recording point and the diaphragm. These imperfections in the record become
audible as scratching and other foreign noises when the sounds are reproduced. The
object in view is to overcome these defects in phonograph-recorders and to make the
reproduced sounds more clear, as also to permit of a more sensitive reproducer being
employed. In the preferred construction of phonograph-recorder, the lover carrying
the recording point is pivoted; one or more of the pivot-bearings being friction-
bearings having a considerable pressure exerted upon them; so that the movements
of the lever, the recording point and the diaphragm are retarded by the friction-
bearings, thus overcoming the momentum of the parts. The lever which is extremely
light is made from a thin plate having sufficient width to afford the desired rigidity
required to withstand the lateral thrust of the recording point. The friction at the
bearings of the pivoted lever is preferably obtained by means of a spring placed under
tension; the tension being preferably adjustable so that the requisite amount of

page_text: friction can be obtained. The pressure of the spring on the bearings of the lever also
serves to take up any lost motion. To prevent the positive attachment of the indenting
point with the diaphragm from straining the diaphragm, the connection is so arranged
as to be capable of yielding in the direction of the length of the carrying lever. This
connection is preferably a link pivoted to the lever as well as to a block cemented or
otherwise secured to the diaphragm. Where the recording point is supported directly
from the diaphragm, no supporting lever or arm being employed, the retarding effect
necessary to overcome the momentum may be produced by means of friction-springs, .
which embrace the recording point and bear against its opposite sides. This mode of
applying the friction may also be used when the recording point is mounted upon an
arin or lever. Instead of employing friction-springs for producing the retarding
effect, a dash pot may be employed for the purpose. It will be seen that all of these
retarding devices are non-resilient and constant in their action, and do not change the
character of the vibrations imparted by the sound-waves to the diaphragm, but only
serve to retard the movement and thus to overcome the momentum. The elastic or
resilient damping devices hitherto used with diaphragms of phonographic apparatus
produce quite a different effect from the non-resilient retarding devices; since by
reason of their resiliency they change the character of the diaphragm-vibrations and
produce false movements which serve to injure rather than improve the character of
the record.
Another improvement in the recorder which adds largely to its efficiency is the
employment for the recording diaphragm of a film or membrane of glass; or its
equivalent, porcelain. What is known as 'microscope glass' of about 005 of an inch
in thickness is preferably employed, although greater thicknesses can be used. The
glass membrane is cut into a circular form of proper size and is clamped between
metallic rings, with some yielding material, such as rubber or paper, placed around
the edges of the glass on both sides. The glass diaphragm is not materially affected
by ordinary variations of heat and moisture; it lias great elasticity and is highly
responsive to sound vibrations. It is capable by reason of its extreme thinness of
sufficient amplitude of vibration to make a sufficiently deep record; hence it does not
get out of adjustment and gives at all times the maximum effects, a uniformly
excellent record resulting. The glass diaphragm is also applicable to reproducers.
Another improvement in the phonograph-recorder consists in holding or clamping
the diaphragm adjustably, so that it can be made more or less sensitive. An increased
efficiency is given the recorder if it be capable of adjustment and of being rendered
more sensitive when used by people having weak voices. With voices of greater
volume it is necessary to reduce this sensitiveness. The diaphragm is made adjustable
by providing a screw-ring bearing upon a follower plate, beneath the edge of which
the diaphragm is clamped.
Another feature of this invention relates to the employment for the diaphragm of
the reproducer of fabric, such as silk bolting cloth, served with shellac or varnish to
give it stiffness and resonance. Such a diaphragm is stretched in the reproducer-
frame, and is used in connection with a reproducing point, which is preferably a
wire of phosphor or aluminium bronze. The said wire is secured to the frame at
one side, projects towards the centre of the diaphragm and substantially parallel
therewith, and is turned down to form the point; the point being connected with
the diaphragm by a solid block of gum, rubber or cork. The reproducer is pro-
vided with an adjustable ring for stretching the diaphragm, which however is not
necessary when a glass diaphragm is employed. The points of both the recorder
and the reproducer are buffed with rouge, to give them a high polish.
Another feature of this invention relates to the preparation of the surface for
receiving the sound-record; such surface being what is termed the phonogram-
blank.
These blanks, after being mounted in the machine, have their recording surface
turned true by a knife which may be carried by the rocking holding arm and whereof
the point is preferably in close proximity to the recording point. The blanks used
with the machine are also preferably adapted to have their surfaces turned off by

page_text: this same cutting tool for the purpose of using them a number of times; so that an
old record may be removed to make place for a new one.
A knife with its cutting edge parallel with the axis of the phonogram-cylinder
and practically at right angles to the track of the record has hitherto been employed
as the cutting tool. It has been found that with blanks coated with wax materials,
the surfaces are not turned off smoothly by the tool on account of their elasticity
and the cohesion of the particles, but that minute cracks or breaks in the surface are
formed, these being parallel with the edge of the cutting tool. To these cracks or
breaks is attributed in a measure the production of foreign sounds by the record.
The cracks or breaks are not so deep as the track made by the recording point; but,
since the recording point meets at one time the resistance due to material of the full
depth of its incision and at another time (when crossing a crack or break in the
surface) a lesser body of material, the record produced is correspondingly affected,
baving irregularities causing false vibrations in the reproducer. The effect of these
cracks or breaks is greatly modified and the inconvenience arising therefrom largely
overcome by so cutting cr turning off the surface of the blank that the cracks are
oblique to the track of tho record or the direction of relative movement of the surface
and the recording point. The improved effect hereby obtained is believed to be due
to the fact that, when the cracks are oblique, the recording point does not meet the
crack across the full width of its advancing edge at one time, but only across a portion
of such edge, the disturbance being thereby extended over a greater time and rendered
more gradual.
Another feature of this invention relates to the location of the cutting knife. Here-
tofore this knife has been placed so as to act on the side of the blank opposite to
the point of the recorder. it has been found that, by placing the cutting edge of the
knife close to the recording point, any imperfection in the turning movement of the
blank will be the same for the cutting tool as for the recording point, so that the old
record can be removed from the surface and a new record cut upon it simultaneously.
It is preferred to attach the knife to the swinging spectacle-frame or to the frame of
the recorder itself, giving it a fixed position. The best construction is to attach the
knife to the spectacle-frame and to mount the recorder adjustably in the eye of the
frame; so that, by first setting the knife to take a proper shaving off the surface and
by then adjusting the recorder while listening at the speaking tube, the proper adjust-
ment of the parts to turn off the blank and make a record simultaneously can be
readily determined.
Another feature of this invention relates to the composition of the surfaces that are
to receive the sound-records. A good material for this purpose is a suitable soap ;
preferably one that is insoluble. Any of the fatty acids, such as oleic, stearic or
margaric acid may be combined with any suitable organic or inorganic base. It is
preferred to use a metallic base, such as lead, magnesium or aluminium combined with
oleic or stearic acid, forming an oleate or stearate of the metal used. Lead seems to
be the best base, and, although the phonogram-blank can be made of one soap, a
mixture of equal quantities of oleate and stearate of lead is preferable. These com-
pounds are preferred because of their superior amorphous quality. The soaps are
made according to the usual well known methods, and if desired they can be mixed
with waxes, gums and resins in any suitable quantities. It has also been found that
gum demar is a highly efficient material for hardening compositions for phonogram-
blanks. The gum demar, may be mixed with any suitable wax, such as ceresin, in
quantities to give the proper degree of hardness. A good proportion for such a
mixture is one hundred parts by weight of gum demar to sixty-five parts of
ceresin.
Dated this 24th day of August 1888.
G. G. M. HARDINGHAM,
191, Fleet Street, London, E.C., Agent for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in Recording and Reproducing Sounds, and in Means
Applicable therefor.
I, GEORGE EDWARD GOURAUD, of Little Menlo, Beulah Hill, Upper Norwood, in
the County of Surrey, late Colonel in the United States Army, do hereby declare the
nature of this invention (a communication to me from abroad by Thomas Alva Edison,
of Llewellyn Park, in the County of Essex, and State of New Jersey, one of 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 :-
The apparatus commonly called the phonograph by means of which it is possible to
record waves, produced in the air by the utterances of the human voice, or by any
other source of sound, and to reproduce those sounds, is now so very generally known,
that it is probably unnecessary to give any description of it in this specification, but
to render untenable any complaint that this specification is insufficient, it is deemed
well to say, that such an apparatus is, so far as regards its leading features, commonly
constructed and that it operates substantially as follows
The waves produced in the air, by a speaker's voice, or other source of sound, are
caused to impinge upon a diaphragm, called the recording diaphragm, which
diaphragm is supported by the frame surrounding one of two apertures, or eyes, of a
part called the spectacle frame. The recording diaphragm is so connected to a part
called the recording style, that when the diaphragm is thrown into vibration by the
sound waves, the recording style is correspondingly moved by the diaphragm. This
style operates upon a suitable surface, kept in continued motion, in such manner as to
form in that surface a record of the waves that operate on the diaphragm. The
surface is commonly carried on a cylinder, which is kept during the working of the
phonograph in continuous uniform rotation, while at the same time a continuous
uniform endway movement, between the recording style and the cylinder,
kept up
either by the end way movement being imparted to the cylinder, or by its being
imparted to a carriage which supports the spectacle frame, which frame as already
stated carries the recording diaphragm and the recording style.
By the combined action of the movement of rotation and of the endway movement,
the record is made upon the surface in a regular helical form. The spectacle frame
is provided with a bored socket, which surrounds a turned pin on the carriage before
mentioned; it is also, as its name would imply, provided with a second frame
surrounding a second aperture or eye, in which is placed a diaphragm called the
reproducing diaphragm. This diaphragm is so connected to an implement (herein-
after called the reproducing implement) that on that implement being moved,
corresponding motions are imparted to the reproducing diaphragm, and by it waves
are generated in the air.
When it is desired to take a record of sound, the spectacle frame is so turned upon
its supporting pin that the eye containing the recording diaphragm is brought into
the proper position for the recording style to operate upon the surface receiving the
record, (the other or reproducing eye being at that time removed from the neighbour-
hood of that surface,) and then the motion of revolution and the endway motion
being set up, and continued by appropriate means, and on speech being uttered to
the recording diaphragm, the recording style makes the record in the surface provided
to receive it, and continues to do so, until the speech or other sources of sound cease,
or until the surface receiving the record is filled therewith. When it is desired to
reproduce from this record the sounds that had produced it, the spectacle frame is
swung partially around the pin which carries it, so as to throw the recording eye
with its diaphragm away froin the neighbourhood of the surface which had received
the record, and so as to bring the reproducing eye with its diaphragm into the position
which had been occupied by the recording eye and diaphragm.
The reproducing implement, being placed in the line of the helical record, which
had been made by the recording style, and the two motions being again given, the

page_text: reproducing implement is caused by the record to make vibrations similar to those
which produced the record, and this implement, as has already been said, gives corre-
sponding movements to the reproducing diaphragm, and thus sets up waves in the
air, similar to those which had been generated by the voice, or other sound, in the
first instance, and these similar waves become audible in the reproduction of
the original sound.
The surface to receive the record is of a suitable character to be properly operated
upon by the.recording style, and is made separate from the revolving cylinder on to
which it is temporarily fixed, so as to admit of that cylinder being clothed with fresh
surfaces.
The first part of this invention relates to methods and apparatus for recording
sound-waves, whether produced by speaking, by music or other sounds, whereby the
records of the sound-waves are given a peculiar form which has been found best
adapted for the clear reproduction of the sounds, and more particularly for the
reproduction of hissing sounds, which latter have not been clearly reproduced by the
apparatus and methods heretofore employed.
All phonographs hitherto made have proved unsatisfactory in consequence of their
lacking clearness and loudness of articulation. This is more particularly due to the
fact that they fail to bring out clearly the hissing sounds, thus making words which
depend upon such sounds for their characteristics generally unintelligible, except by
aid of the context.
A microscopical examination of such phonograph-records shows that the records
of the waves are symmetrical in shape, each wave rising and falling on the same
gradual sinuous curve. The waves for the hissing sounds also appear longer and
of less depth and hence are more gradual in their rise and fall than those for vowel
sounds.
The imperfection of phonograph-records arises from the symmetrical and gradual
rise and fall of the recorded waves, and especially of the recorded waves representing
hissing sounds, which do not move the reproducing diaphragm with sufficient
abruptness to reproduce the sound waves with clearness. To overcome this difficulty,
the form of the recorded waves is modified, so that, instead of being a simple
sinusoidal symmetrical curve with the greatest depth at the centre of each recorded
wave, the curve is more abrupt at one end than at the other. This is accomplished
by so controlling the movement of the recording style with reference to the relative
movement of its point and the recording surface, that instead of acting perpendicularly
to the line of advancing movement, the recording style point moves obliquely to such
line, so that in one direction the recording style point moves to some extent with the
surface receiving the record, and in the other direction the said point moves to some
extent against or opposite to the movement of the surface receiving the record. By
regulating these relative movements, it has been found that the records of waves can
be given the desired abruptness at one end; i.e., the point of greatest depth of the
recorded wave can be transferred from the centre of the wave to near either end. It
is preferable to make this abruptness at the end rather than at the beginning of
each wave, since in the former case the point of the reproducing implement passes
down the gradually declining surface of the wave to its extreme depth and then rises
suddenly at the end of the wave without producing audible disturbances of the
recorded sound; whilst, in the latter case, false sounds are produced, which is
attributed to the point of the reproducing implement jumping off the abrupt corners
of the records and striking the bottom of the wave record with sufficient force to
rebound, making false vibrations which are audible.
This part of my invention is illustrated in Figs. 1 to 16 of the accompanying
drawings. Figs. 1 and 2 represent on an enlarged scale the form of the records of
waves for vowels and for hissing sounds respectively in phonograph-records heretofore
produced; whilst Figs. 3 and 4 represent on an enlarged scale the form of the records
of waves for vowels and for hissing sounds respectively in phonograph-records produced
by the employment of this invention. Figs. 5 and 6 are views illustrating the dynamic
effects of the pure and modified wave records. Fig. 7 is a view, principally in

page_text: diagram, illustrating a suitable arrangement for the recording style point; the dotted
lines shewing the effect of changing the position of the pivot of the lever which
carries such recording style. Fig. 8 is a view similar to Fig. 7, but shewing a flat
instead of a cylindrical record surface to receive the record. Fig. 9 is a view
illustrating the accomplishment of the same end by arranging the recording style
obliquely to the surface receiving the record. Fig. 10 is a view illustrating the
use of a reproducing implement with records such as would be produced by the
arrangement represented in Figs. 7, 8 and 9. Figs. 11 and 12 are an elevation and a
top view respectively of a recording style acting parallel with the surface receiving
the record and employing this invention. Figs. 13 to 16 are views in vertical
section of other forins of the recorder adapted for carrying out the present
invention.
With reference to Figs. 1 to 10 just referred to, the sinuous line A (Fig. 1)
represents, in very enlarged diagram form, the recorded wave line heretofore produced
in phonographs for vowel sounds. It will be observed that these waves have the
greatest depth at the centre of their length and that they rise symmetrically in each
direction from the central point. The sinuous line (Fig. 2) is a similar repre-
sentation of the wave line for hissing sounds and on the same scale. It will be seen
that these waves also have their greatest depth at their centres but that they are
longer and have less depth than the waves for vowel sounds and hence are much more
gradual. Since the loudnoss of the sounds produced by the phonograph reproducer
depends upon the sharpness of the impulses, it is evident that these hissing sounds
will be very feeble. In fact in many cases they are not audible at all, and words
depending on them for their characteristics are not reproduced with clearness of
articulation.
Now it will be seen that if the form of the waves in recording is changed so as
to transfer the point of greatest depth from the centre to near the end of each
wave, the impulse produced by the recorded waves in the passing of the point of the
reproducing implement over them will be greatly sharpened. The lines and D
(Figs. 3 and 4) represent wave records of this modified character and such as aro
produced by the employment of this invention.
The difference in the action of the gradual and abrupt waves is believed to be
capable of explanation by the application of the simple laws of dynamics. In Fig. 5,
which shows an ordinary wave record, the reproducing implement point a is lifted
the distance while the surface having the record is travelling the distance zz.
In Fig. 6, which shews a modified or sharpened wave record, the reproducing
implement point is lifted the same distancey while the surface bearing the record
is travelling the shorter distance x¹³.
Assuming equal rates of travel for the surfaces bearing the records, the distance ¹z
being one-half of xz, it will be seen that in the second case double the velocity will
be given the reproducing implement point in lifting it through the same distance,
and hence, without increasing the depth of the waves, the sound effects are
increased.
With a view to modifying the records of the waves and the making them different
in form from the ordinary records of sound waves by rendering them abrupt at one
end, the relations between the recording style point and the surface receiving the
record are controlled. It has been found that by giving the parts such a relation
that the reciprocating movements of the recording style point are oblique rather than
substantially perpendicular to the line of movement of the surface receiving the
record, the proper effect is produced; the greater the degree of obliquity, the more
abrupt at one end are the records of the waves. This increase of obliquity may be
done in a variety of ways, by adjusting the position of the pivot of the lever carrying
the recording style and by changing the angular position of the recorder
diaphragm.
In. Fig. 7 the surface E receiving the record is represented as carried on a revolving
cylinder. The recorder diaphragm is shewn above the cylinder E at F. The
recording style bi connected with the centre of the diaphragm and is mounted on a

page_text: lever c pivoted at the point c'. This lover is short and its pivot, as shown, is located
to the left of and above the point of the recording style. The direction of movement
of the recording style point is represented by the line d. It will be seen that, as the
point moves forward into the surface receiving the record, the point will advance
against the movement of the surface and the effect will be a prolongation of the first
part of the record of the wave, while when the point retreats it will move with the
surface and the effect will be to shorten and make abrupt the second part of the
record of the wave. If the lever c were pivoted at c², the movement of the recording
style point would be as represented by the line d'; and if pivoted at c³ the movement
of the point would be as represented by the line . Either of these two latter move-
ments of the recording style point would be substantially perpendicular to the surface
receiving the record and the desired modification of the wave record would not be
effected. To attain the best results, the lever carrying the recording style should be
short and should have its pivot within the edge of the diaphragm, and the pivot
should also be, as shewn, above the point; or the equivalent of these conditions should
be secured. The shorter the lever and the further the distance of the pivot above the
point, the more oblique will be the movement of the point. The proper conditions
can be secured by advancing in either of these directions; i.e., if the pivot be placed
a sufficient distance above the point, the lever may be longer and may extend beyond
the diaphragm while if the lever be made exceedingly short, the distance of the
pivot above the point may be greatly lessened. The effect of bringing the pivot into
the same plane as the point is shewn in Fig. 7 by the line 2, and in Fig. 8 by the
line e In Fig. 8 the same arrangement is illustrated as in Fig. 7 with the exception
that the surface E' receiving the record is flat instead of cylindrical. The line of
movement of the recording style point when the pivot is placed above the flat
surface is shewn at e, while if the pivot of the lever were situated as low down as
the flat surface at the point marked by a cross, the line of movement of the recording
style point would be, as at e¹, substantially perpendicular to the surface receiving the
record and hence not effective for the purposes of this invention.
By changing the angular position of the recording diaphragm with relation to the
surface receiving the record, a long lever carrying the recording style point can be
employed, as shown in Fig. 9; but this is obviously equivalent to placing the pivot
further above the point as shewn by the dotted lines in this figure. In the Figs. 7,
8 and 9 it has been deemed well for the sake of not confusing the figures to omit the
supports on the diaphragm frame which carry the ends of the spindles forming the
pivots of the levers c; such supports are shewn as in Figs. 11 and 12. Although
in several of the Figures where the recording style is carried on a lever, the style is
shewn as directly connected with the recording diaphragm, it is preferred to make
that connection by means of links such as are shown in Figs. 18, 19, 34 and 36.
The reproducing implement (Fig. 10) may be a fine wire point connected with
the diaphragm F by a solid block of india-rubber or other suitable material f. The
point of the reproducing implement is bent downwardly into an inclined position and
is adapted to follow the records produced by the recording style points hereinbefore
described with reference to Figs. 7, 8 and 9.
In Figs. 11 and 12 is illustrated the use of the invention with recording stylos
having points reciprocating in the plane of the surface receiving the record instead
of in a plane perpendicular to such surface. b is the point carried by the elbow
lever c and attached to the recording diaphragm F at f. The pivot of the elbow
lever is the spindle s carried in two supports s¹ s¹.
It is obvious that the placing of the pivot s to the left of the point b has the samo
effect in giving an oblique motion to that point in this arrangement as had the
placing of the pivot above the point as shewn in Figs. 7, 8 and 9.
In Fig. 13, the recording style point is pivoted to the centre of the recorder
diaphragm. A rigid arm g, projecting from the ring or frame of the recording
diaphragm, bears at its end against the bevelled side of the recording style, which
is held against the arm by a spring g'. According to this arrangement, the recording
style point will have a movement oblique to the surface receiving the record.

page_text: In Fig. 14, the same object is accomplished by connecting the rigid arm with the
pivoted recording style by a pin working in an oblique slot.
In Fig. 15, the recording style 3 is mounted upon the carrying lever c between
the pivot of the lever and its connection with the recording diaphragm.
In Fig. 16, the recording style is pivoted on the diaphragm and has a tail-
piece which rests on a rigid arm g² against which it is held by a spring.
The second part of this invention relates to methods and apparatus for recording
the sound-waves whereby the wave record will be more efficiently produced in the
surface receiving the record.
In recording sounds, or sound waves, a groove is made in the solid material
forming the surface receiving the record by means of a recording style connected
directly or indirectly with the diaphragm of the recorder, and this groove varies in
depth or shape accordingly as the recording style is advanced or is withdrawn by the
vibrations of the recording diaphragm, thus producing a wave record from which the
sounds are reproduced, as is well understood.
Heretofore the recording style point used has been constructed so that in forming
the groove it removed the material by a scraping action. This was due to the fact
that the operating edge of the recording style used was perpendicular to the surface
receiving the record or in some cases it even receded from the perpendicular, the
result being a scraping rather than a true cutting of the material. The scraping
action has been found to be productive of false vibrations which become a part of the
record, and the presence of which give rise to scratching and other foreign noises
when the sounds are reproduced. This difficulty is overcome by employing a
recording style having its operating edge made as a true cutting tool with a cutting
edge in advance of the stock of the tool.
This feature of the invention is illustrated by Figs. 17 and 18; Fig. 17 being a
view on an enlarged scale illustrating the formation of the record by a scraping style
as heretofore, and Fig. 18 a similar view illustrating the formation of a record
according to the improved method and by means of a recording style having a true
cutting action. H is the surface receiving the record, which surface may be regarded
as a wax composition capable of receiving from the recording stylo the records of the
sound waves.
It is given a movement in the direction of the arrow.
or operative edge
Heretofore the recording style 6* has had its advanced
perpendicular to the surface receiving the record (or even receding from it), as shewn
in Fig. 17. This disposition produced the record by a scraping action. According
to the improved method, the recording style 46 (Fig. 18) is a cutting tool having
a cutting edge in advance of the stock of the tool. This produces the record
by a true cutting action. The recording_style_¿*, Fig. 17, is attached directly and
only to the diaphragın F; hence the wave record is composed of waves having a
symmetrical rise and fall with the deepest part of each wave at its centre. The
point in Fig. 18 is mounted on a pivoted lever 18 connected with the diaphragm F
by a pivoted link f¹. The direction of movement of the cutting edge of the
Hence it will be seen that, as
recording style is indicated by the dotted line d.
explained in an earlier part of this specification, the recording style point acts
obliquely to the surface receiving the record and produces records of waves which
records begin gradually and end abruptly. It will be seen that the wave record is
of such a character. By the movement of the surface receiving the record and by
the oblique action of the recording style point, the heel of the cutting tool forming
the recording style point is kept clear in operation.
The third part of this invention relates to improvements in phonograph-recorders,
whereby the imperfections arising from the momentum of the moving parts and other
defects in their operation are overcome.
In experimenting with the improved phonograph, it has been discovered that
imperfections are produced in the record made by the machine by reason of the
momentum of the recorder-diaphragm and attached parts, also by reason of lost
motion when the recording style is mounted, as it should be, on a pivoted lever, and
also by reason of the straining of the recording diaphragm due to the attachment of
B

page_text: the recording style to such diaphragm and to the differences in the direction of
movement of the recording style point and the diaphragm. These imperfections in
the record become audible as scratching and other foreign noises when the sounds
are reproduced. The object in view is to overcome these defects in phonograph-
recorders and thus to make the reproduced sounds more clear, as also to permit of a
more sensitive reproducer being employed. In the preferred construction of
phonograph-recorder, the lever carrying the recording style is pivoted; one or more
of the pivot-bearings being friction-bearings having a considerable pressure exerted
upon them, so that the movements of the lever, the recording style and the diaphragm
are retarded by the friction-bearings, thus overcoming the momentum of the parts.
The lever, which is extremely light, is made from a thin plate having sufficient width
to afford the desired rigidity required to withstand the lateral thrust of the recording
style point. The friction at the bearings of the pivoted lever is preferably obtained
by means of a spring placed under tension; the tension being preferably adjustable
so that the requisite umount of friction can be obtained. The pressure of the spring
on the bearings of the lever also serves to take up any lost motion. To prevent the
positive attachment of the recording style with the diaphragm from straining the
diaphragm, the connection is so arranged as to be capable of yielding in the direction
of the length of the carrying lover. This connection is preferably a link pivoted to
the lever as well as to the block cemented or otherwise secured to the diaphragm.
Where the recording style is supported directly from the diaphragm, no support-
ing lever or arm being employed, the retarding effect necessary to overcome
the momentum may be produced by means of friction-springs which embrace the
recording style and bear against its opposite sides. This mode of applying the
friction may also be used when the recording style is mounted upon an arm or lover.
Instead of employing friction-springs for producing the retarding effect, a dash-pot
may be employed for the purpose. It will be seen that all of these retarding
devices are non-resilient and are constant in their action, and do not change the
character of the vibrations imparted by the sound-waves to the diaphragm, but only
serve to retard the movement and thus to overcome the momentum. The clastic or
resilient damping devices hitherto used with diaphragms of phonographic apparatus
produce an effect quito different from that of the non-resilient retarding devices
above mentioned; since by reason of their resiliency they change the character of
the diaphragm vibrations and produce false movements which serve to injure rather
than to improve the character of the record.
Another improvement in the recorder which adds largely to its efficiency is the
employment for the recording diaphragm of a film or membrane of glass; or its
equivalent, porcelain. What is known as microscope glass of about 005 of an inch
in thickness is preferably employed, although greater thicknesses can be used. The
glass membrane is cut to a circular form and is clamped between metallic rings, with
some yielding material, such as rubber or paper, placed around the edges of the
glass on both sides. The glass diaphragm is not materially affected by ordinary
variations of heat and moisture, hence it does not get out of adjustment; it has great
elasticity and is highly responsive to sound vibrations. It is capable, by reason of
its extreme thinness, of sufficient amplitude of vibration to make a sufficiently deep
record; and to give at all times the maximum effects, an uniformly excellent record
resulting. The glass diaphragm is also applicable to reproducers.
Another improvement in the phonograph-recorder consists in holding or clamping
the diaphragm adjustably, so that it can be made more or less sensitive. An increased
efficiency is given the recorder if it be capable of adjustment and of being rendered
more sensitive when used by people having weak voices. With voices of greater
volume it is necessary to reduce this sensitiveness. The diaphragm is made adjustable
by providing a screw ring bearing upon a follower plate, beneath the edge of which
the diaphragm is clamped.
These features of the invention are illustrated in Figs. 19 to 29 of the accompanying
drawings. Fig. 19 is a vertical section of the preferred form of recorder; Fig. 20
is an under-side view of the same. Fig. 21 is a vertical section of the recorder,

page_text: shewing a modification of the connection between the carrying lever and the
diaphragm, Fig. 22 being an under-side view of the same; Fig. 23 is a section
through the centre of the diaphragm of the recorder (Figs. 21 and 22) shewing in
elevation the connection between the carrying lever and the diaphragm; Fig. 24 is
a vertical section of a recorder shewing a modification of the means for producing
the retarding friction; Fig. 25 is an under-side view of the same; Fig. 26 is a
vertical section of a recorder having the recording style supported from the diaphragm,
Fig. 27 being an under-side view of the same; Fig. 28 is an under-side view of a
recorder having the recording style supported by a lever and having the friction-
springs bearing directly on the point; and Fig. 29 is a side view of a recorder
shewing the employment of a retarding dash-pot.
Referring to Figs. 19 and 20, which show the preferred form of phonograph
recorder, the diaphragm F is a thin plate of microscope glass, which is clamped
between plates by means of the adjusting ring, the edges of the glass diaphragm
being protected by rubber rings. The recording style is preferably mounted upon
or forms part of a lever 10 which is made from thin plate metal, in order to give it
lightness. This lever 10 is mounted upon a long bearing pin ", which is pivoted
in the ends of a yoke 6 secured rigidly to the bottom of the ring i. Between the
back of the yoke 612 and the bearing pin is a semi-elliptical spring which hears
against the bearing pin and is adjusted in its tension by means of a screw "
passing through the back of the yoke and bearing against the centre of the spring.
The lever is connected with the centre of the diaphragm by means of a link 618
which is pivoted to the lever and is also pivoted to a small metal or other block
cemented to the centre of the diaphragm.
The tension of the spring 13 produces considerable friction at the bearings of the
pin, and hence the movements of the diaphragm, of the recording style, and of
the carrying lever are retarded by this friction, the momentum of these parts being
therchy overcome. Lost motion at the bearings is also taken up by means of the
tension of this spring. The pivoted link 6 forms a positive connection between the
recording style and the diaphragm, so that the movements of the diaphragm are
communicated positively to the recording point; at the same time the link yields
in the direction of the length of the carrying lever, so that the diaphragm is not
subjected to strain owing to the difference in the direction of movement of the
recording style and of the diaphragm. This positive connection, which is free to
yield in a direction at right angles to that of the movement of the diaphragm, also
provents the diaphragm being strained, a result which would ensue were a rigid
attachment cemented to it. It will be seen that if the link 61 were rigidly connected
with the lover 610, the effect would be to strain the diaphragmn in cementing this rigid
connection to it, since the diaphragm would be pressed in by the link in securing the
cement, and when it resumed its normal position, there would be a strain between
the diaphragm and the connection.
In Figs. 21, 22 and 23 is shewn the same instrument as that just described with
reference to Figs. 19 and 20, with the exception that for the link an arch ¹ of
wire is substituted, the latter being cemented at two points to the diaphragm and
passing through the end of the lever 10. This arch is practically rigid in the
direction of the movement of the diaphragm, thus forming a positive connection
between the diaphragm and the recording point, while it is capable of yielding in the
direction of the length of the lever 18, thus preventing the diaphragm from being
strained.
In Figs. 24 and 25, the friction is produced by means of a spring " which is
secured to one side of the bottom of the ring i. The spring crosses the said ring and
has a forked end which embraces the long bearing pin 18 and bears with considerable
pressure against a friction-disc upon such bearing pin. This pressure may, if
desired, be made adjustable in any convenient manner, such for example as that
shewn in Fig. 27 as applied to each one of the pair of springs there used. The
pressure of the spring 6 on the disc 61 forces the bearing pin 68 longitudinally

page_text: against its bearing at one end, which bearing may be provided with a friction-
washer of leather or other suitable material. Advantage is taken of this figure to
shew that the lever-carried recording style may be directly connected with the
diaphragm by cement; this is a construction which may be employed, but it is not
so efficient as the yickling but positive connection before described.
In Figs. 26 and 27 is shewn a recorder having the recording style 1,21 supported
directly by the diaphragm, there being no lever or arm to take the lateral thrust.
The retardation in this case is produced by means of two friction-springs,
which are secured to a block attached to the ring i of the recorder; the said
springs embracing at their inner ends the recording style upon the opposite sides
of which they bear with considerable pressure, so that the recording style in moving
will be retarded by the friction of the springs on its sides. Adjusting screws 62 may
be used to adjust the pressure of these friction-springs.
This mode of producing the friction may be employed with recording styles
mounted upon levers as shown in Fig. 28. This form does not take up the lost
motion at the pivots of the lever; but the friction being applied directly to the
recording style, the retarding action is effectively produced."
In Fig. 29 a small dash-poi 60, connected with the outer end of the lever carrying.
the recording style, is employed to retard the momentum of the parts.
It will be observed that all the retarding devices are non-resilient in their action
and afford a constant resistance to the movement of the parts at every point, in this
respect differing widely from the damping devices that have heretofore been employed.
The glass diaphragm has the advantages before pointed out, and the adjustable
ring, shown in Figs. 19 and 21, enables the diaphragm to bo clamped adjustably, so
as to be more or less sensitive as before explained.
Another feature of this invention relates to the employment for the diaphragm of
the reproducer of fabric such as silk bolting cloth, served with shellac or varnish to
give it stiffness and resonance.
Such a
diaphragm is stretched in the reproducer-
frame and is used in connection with a reproducing implement, which implement is
preferably a wire of phosphor or of aluminium bronze. The said wire is secured to
the frame at one side, projects towards the centre of the diaphragm, being substantially
parallel therewith, and is turned down to form the point; the point being connectod
with the diaphragm by a solid block of suitable material, such as gum rubber or cork.
The reproducer is provided with an adjustable ring for stretching the diaphragm,
which however is not necessary when a glass diaphragm is employed. The points of
both the recording style and of the reproducing implement are buffed with rouge, to
give them a high polish.
These features of the invention are illustrated by Fig. 30 of the drawings, which
shews the reproducer in section.
F is the diaphragm made of a fabric such as silk bolting cloth stretched and then
shellacked or varnished either before or after it is secured in the frame of the
reproducer. This frame is made in two portions, which are held together in any
convenient manner, such as by screws having the diaphragm nipped between them.
The socket m has a screwed portion m' into which is screwed a bush N, pressing on a
ring N1, which bears on the diaphragm near its edge to stretch it and to regulate the
tension. The reproducing implement is formed of a metal wire 67 secured to the
frame at one side and extending towards the centre of the diaphragm where its
end is bent downwardly as shewn. This wire is made so as to tend to spring away
from the diaphragm, as shewn by the dotted lines, but is prevented from doing so by
its being attached to the centre of the diaphragm by a solid block of suitable
material, such as gum rubber or cork, which is cemented both to the diaphragm and
to the wire, the wire being drawn in for the purpose so that the diaphragm will be
normally held under tension.
Another feature of this invention relates to the preparation of the surface for
receiving the sound-record; such surface being what is termed the phonogram-
blank.

page_text: These blanks, after being mounted in the machine, have their surface which receives
the record turned true by a knife which may be carried by the rocking holding arm
and whereof the point is preferably in close proximity to the recording style. The
blanks used with the machine are also preferably adapted to have their surfaces
turned off by this same cutting tool for the purpose of using them a number
of times; so that an old record may be removed to make place for a new one.
A knife, with its cutting edge parallel with the axis of the phonogram-cylinder
and practically at right-angles to the track of the record, has hitherto been employed
as the cutting tool. It has been found that with blanks coated with wax and similar
yielding materials the surfaces are not turned off smoothly by such a tool on account
of their elasticity and the cohesion of the particles, but that minute cracks or breaks
in the surface are formed, these being parallel with the edge of the cutting tool.
To these cracks or breaks is attributed in a measure the production of foreign sounds
by the record. The cracks or breaks are not so deep as the track made by the
recording style; but, since the recording style point mects at one time the
resistance due to the material of the full depth of its incision and at another time
(when crossing a crack or break in the surface) meets the resistance due to a lessor
body of material, the record produced is correspondingly affected, having irregu-
larities causing false vibrations in the reproducer. The effect of these cracks or
breaks is greatly modified and the incovenience arising therefrom largely overcome
by so cutting or turning off the surface of the blank that the cracks are oblique to
the track of the record or the direction of relative movement of the surface and the
recording style point.
The improved effect hereby obtained is believed to be due to the fact that, when
the cracks are oblique, the recording style point does not meet the crack across the
full width of its advanced edge at one time, but only across a portion of such alge,
the disturbance being thereby extended over a greater time and rendered more
gradual.
This feature of the invention is illustrated by Figs. 31 to 33. Fig. 31 is a view
shewing the phonogram-blank under the operation of the cutting tool; and Figs. 32
and 33 are views on an enlarged scale shewing the relation between the
recording style point of the phonograph and the cracks in the surface receiving the
record.
The point of the cutting knife K is oblique as shewn in Fig. 31; the cracks
produced thereby in the wax recording surface being oblique to the track of the
record made by the point 620 of the recording style.
In Figs. 32 and 33 are shewn in horizontal section the recording style point 6,29,
while represents the cracks in the surface receiving the record. If these cracks
be parallel with the advancing edge of the recording style point, as shewn in Fig. 32,
the recording style point will meet the cracks at the same time across the full width
of its advanced edge; while if the racks be oblique, as in Fig. 33, only a portion of
the advanced edge of the recording style point will be in the crack at any one time,
and the disturbing effect of the crack will be distributed over a greater space of time
and hence will be more gradual.
It
Another feature of this invention relates to the localisation of the cutting knife.
Heretofore this knife has been placed so as to act on that side of the phonogram
blank which is opposite to the side on which the point of the recorder style acts.
has been found that, by placing the cutting edge of the knife close to the recording
style point, any imperfection in the turning movement of the phonogram blank will
be the same for the cutting tool as for the recording style point, so that the old
record can be removed from the surface and a new record can he cut upon it
simultaneously. It is preferred to attach the knife to the swinging spectacle-frame
or to the frame of the recorder itself, giving it a fixed position. The best construction
is to attach the knife to the spectacle-frame and to mount the recorder adjustably in
the eye of the frame; so that, by first setting the knife to take a proper shaving off
the surface and by then adjusting the recorder while listening at the speaking tube,

page_text: the proper adjustment of the parts to turn off the blank and make a record simul-
taneously can be readily determined.
This part of the invention is illustrated in Figs. 34 to 37. Fig. 34 is a sectional
view of the phonograph, shewing the knife in position for operation; Fig. 35 is an
under-side view of a part of the spectacle frame, shewing the knife and the recorder;
Fig. 36 is a view similar to Fig. 34 shewing different means for adjusting the
recorder, and Fig. 37 is a top view of the spectacle-frame with the adjusting means
shewn in Fig. 36.
Lis the rotating phonogram cylinder of the machine carrying the phonogram
blank M. The advancing rocking holding arm N* has pivoted to its upper end,
the swinging spectacle-frame O, having two eyes, one of which carries the recorder
and the other the reproducer. This frame is swung laterally to bring either of these
instruments into operative relation with the surface of the phonogram-blank. The
recorder and reproducer are instruments complete in themselves and are separable from
the machine, each being carried by an annular frame P, which is inserted in one of the
eyes of the spectacle-frame and is secured therein by a set-screw p. The recording
style point projects beyond the ring frame P in order to operate on the surface
of the phonogram blank. Qis the knife or turning off tool, preferably attached to
the under side of the swinging spectacle-frame just above the eye holding the
recorder. The knife is fastened in position tightly to the spectacle-frame and projects
towards the point of the recording style, which it approaches as closely as possible,
and terminates in an oblique cutting edge. The eye of the spectacle-frame carrying
the recorder is provided with a finger O* through which passes a set-screw 01
resting on the straight guide-rest 02 along which it travels. By adjusting the
screw O¹, the cutting knife and the recorder are simultaneously moved towards the
surface of the phonogram-blank or are moved away therefrom. In order to secure
the proper relative adjustment between the recording style point and the cutting knife,
the recorder is made independently adjustable in the eye of the spectacle-frame,
so that, independently of the guide-rest adjustment, the recording style point can be
adjusted either towards the surface of the blank or away from that surface. This
adjustment of the recorder may be secured in various ways. Two means for securing
the adjustment are illustrated by the drawings. In Fig. 34 a screw-ring R is shown,
which embraces the edge of the annular frame P of the recorder and forms a
shoulder for such frame, the same resting upon the spectacle-frame. By adjusting
the screw-ring R, the depth to which the recorder enters the eye of the spectacle-
frame can be varied and the recording style point can be moved towards the surface
receiving the record or can be moved away therefrom. A slot and pin
be employed to prevent the recorder turning whilst the adjusting screw R is being
operated.
may
In Figs. 36 and 37 the annular frame P of the recorder is shewn as hinged upon
the spectacle-frame and as having an upwardly-extending lug pl arranged between
two lugs on the spectacle-frame, the said frame P being pivoted upon a cross-pin
which is removable. Opposite the lug p', the annular frame P of the recorder is
provided with a lug p² through which an adjusting screw p* works and bears against
the top of the spectacle-frame. It is evident that by adjusting the screw p³ the
recorder will be moved more or less into or out of the eye of the spectacle-
frame. With either of the means for adjustment described, the set-screw
used to secure the recorder rigidly in position after the proper adjustment has been
obtained.
is
In adjusting the parts, the recorder may be first raised so as to clear the surface,
and the screw O' can then be adjusted to let the knife down upon the surface of the
blank until it is seen that the knife is cutting a proper shaving to remove the old
record. The speaking tube, not shewn in the drawing, is then connected with the
recorder and is held to the car of the operator, while the recorder is adjusted towards
the surface that receives the record by turning the screw-ring R or the adjusting
screw p³. When the operator ascertains that the recording style point is tracking

page_text: properly by hearing the continuous and uniform sound of the recorder in operation on
the surface, he knows that the proper adjustment has been secured. He then binds
the recorder in place by means of the set-scrow p. The adjustment being once
secured, the relation between the recording point and the cutting knife will be
maintained for subsequent manipulations of the guide-rest adjustment, so that tho
screw O¹ can be adjusted to lower the recording point and the cutting knife simul-
taneously. It is only when the recorder is removed for any particular purpose and is
again placed in position that the parts have to be readjusted. It will be seen that the
cutting knife, being mounted directly upon the spectacle-frame, swings with such
spectacle-frame, and is with the recorder brought into and out of operation by the
lateral swinging of the spectacle-frame.
Instead of attaching the knife to the spectacle-frame, it may be secured to the frame
of the recorder itself, as shewn in dotted lines in Fig. 35, in which position it will
have many of the advantages of being attached to the spectacle-frame; since the point
of the cutting knife will be fixed with reference to the recording style point and the
cutting knife will be swung away from the record with the recorder.
Another feature of this invention relates to the composition of the surfaces that are
to receive the sound-records; i.e., the phonogram blanks. A good material for this
ригрозе is a suitable soap preferably one that is insolublo. Any of the fatty acids,
such as oleic, stearic or margaric acid may be combined with any suitable organic or
inorganic base. It is preferred to use a metallic base, such as lead, magnesium or
aluminium, combined with oleic or stearic acid, forming an oleate or stearate of the
metal used. Lead seems to be the best base, and although the phonogram-blank can
be made of one soap, a mixture of equal quantities of oleate and stercate of lead is
preferable. These compounds are preferred because of their superior amorphous
quality. The soaps are made according to the usual well-known methods; and they
can be mixed with waxes, gums and resins in any suitable quantities for varying the
degree of hardness. It has been found that gum demar is a highly efficient material
for hardening compositions for phonogram-blanks. Instead of employing soap, the
gum demar may be mixed with any suitable wax, such as ceresin, in quantities to give
the proper degree of hardness. A good proportion for such a mixture is one hundred
parts by weight of gum demar to sixty-five parts of ceresin.
In Fig. 38 is shewn in section a phonogram-blank which may be made of the
materials or compounds mentioned. It may be made entirely of such materials or
compounds; or a backing of paper or other suitable material may be employed upon
which the material forming the surface which receives the record may be placed,
such paper backing being indicated by dotted lines in Fig. 38.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I claim :-
1. The method of and apparatus for recording sound waves and for reproducing
sounds by the production in a phonogram of sound-wave records made more abrupt at
one end than at the other, and the employment of such records to reproduce sounds
substantially as herein described.
2. The method of and apparatus for recording sound waves substantially as herein
described, the cutting edge of the recording style being in advance of the stock of the
ool and having a true cutting action.
3. The employment in a phonograph recorder of a non-resilient retarding device for
overcoming the momentum of the diaphragm and of the attached parts by
constantly retarding the movements thereof in both directions, substantially as herein
described.
4. The employment in a phonograph recorder of an adjustably-clamped diaphragm,
substantially as herein described.
5. The employment in a phonograph recorder or reproducer of a diaphragm com-
posed of glass or porcelain, substantially as herein described.
6. The method of and apparatus for turning off the recording surface by the

page_text: emproуm
described.
20
D
7. Providing a phonograph with a turning-off knife arranged with its cutting
edge in close proximity to the recording style so as to act simultaneously therewith,
substantially as herein described.
8. In a phonograph, mounting the recorder adjustably in the eye of the spectacle-
frame, substantially as herein described.
9. A phonogram-blank or surface to receive the record composed of an insoluble
soap or soaps or mixture in which soap is the principal ingredient, substantially as
herein described.
10. A phonogram blank or surface to receive the record composed of soft
waxy material mixed with gum demar to harden the same, substantially as herein
described.
Dated the 20th day of June 1880
G. G. M. HARDINGHAM,
191, Fleet Street, London, E.C., Agent for the Applicant.