AN ELECTRICAL MUSICAL INSTRUMENT
Year: 1881

page_text: LETTERS PATENT to William Ford Schmoele and Alexis Mols, of Antwerp, in
the Kingdom of Belgium, Engineers, for an Invention of "AN ELECTRICAL
MUSICAL INSTRUMENT."
PROVISIONAL SPECIFICATION left by the said William Ford Schmoele
and Alexis Mols at the Office of the Commissioners of Patents on the
27th July 1881.
WILLIAM FORD SCHMOELE and ALEXIS MOLS, of Antwerp, in the Kingdom of
Belgium, Engineers. AN ELECTRICAL MUSICAL INSTRUMENT."
«
This Invention relates to an instrument which may be played by means of a
keyboard of its own, or which may be applied to a piano, and be caused to play
upon the same automatically. In the former case it acts as a reed instrument
alone, in the latter case the music of the piano may be produced alone or be
combined at pleasure with that of the reed notes. It is mainly intended to serve
the latter purpose. This apparatus may briefly be divided into two parts, the
pneumatic and the electro-magnetic. The first provides the motive power, the
second times and regulates the application of the motive power. The passage of
the electric current is determined by a specially constructed sheet or web of
perforated paper or card which constitutes the music, and which is drawn forward
by rollers at a regulated speed. A series of metallic fingers overlie a metallic
cylinder connected with a battery, and the perforated paper is caused to pass
between the said cylinder and the ends of the metallic fingers. Whenever a finger
coincides with a perforation contact takes place, and the current of electricity flows
to a series of electro-magnets which instantly allow the pneumatic action to operate
upon a series of strikers whereby the keys of the piano are actuated.
The Invention also relates to novel means for giving gradation of tone to the
music, for accentuating and giving expression to particular notes or passages, and
for prolonging certain sounds as may be desired.
The pneumatic action, which may be either that of suction or pressure, is
established by a pair of bellows worked by a hand lever. or by rotary motion.

page_text: This motion imparted to the bellows causes the alternate inflation and collapse of
a pump consisting of 2 pairs of air vessels or bellows, the vessels of each pair
being connected together by coupling rods, and being also connected by links with
discs on the ends of a spindle which is caused to rotate as the air vessels are
alternately inflated and collapsed. Uniformity of speed is provided for by a flyer
connected with the spindle by a worm and worm-wheel. This spindle is connected
by suitable gearing with the roller for drawing forward the perforated sheet of
music, which is therefore advanced at a speed proportionate to that at which the
pneumatic system is worked.
With this introduction the construction and action of the apparatus, as applied
to the automatic playing of a piano, will be readily understood, and the several
points of novelty in the Invention may be dealt with seriatim.
The instrument is constructed so as to fit on to the front of a pianoforte, a
considerable part of the mechanism occupying the space under the keyboard and
between the legs of the piano. When thus placed a series of strikers tipped with
felt and pivotted at their rear ends will overlie the several keys of the piano,
one striker being over the key of each note, natural and sharp.
Beneath the keyboard of the piano is a series of pneumatic levers in connection
with the main air bellows acting as an exhaust, and serving when in communication
with the series of pneumatic levers is established, to exhaust the air from thein and,
cause them to collapse by atmospheric pressure on their exterior.
The com-
munication is established by the action of an electro magnet upon an armature
lever, the short arm of which is drawn down the long arm thereof, lifting a valve
which shuts off the interior of the first pneumatic lever from the atmosphere and
opens it to the action of the exhaust bellows by which it is instantly collapsed.
As it collapses a tail piece rigidly connected to its upper surface is elevated, and a
second valve is caused to shut against the pressure of the atmosphere and open
the interior of a second larger pneumatic lever to the suction of the exhaust
bellows, whereby it in 'turn is instantly collapsed.
This second pneumatic lever is connected to one of the strikers overhead by
means of a wire and adjusting screw nut, so that directly the current passes to the
electro magnet of one of the double sets of pneumatic levers just described, the
pneumatic power is allowed to forcibly draw down the striker in question which
at once operates its underlying key.
The strikers are also each connected with another pneumatic system for
_ diminishing_the_sound_and_for_producing_gradation of tone. This is effected by
causing the collapse of a triple set of pneumatic levers, the largest of which puts
tension upon one or more spiral springs, preferably three, attached to the striker,
and partially counteracts to the direct pull of the first described pneumatic levers.
The strikers may on the other hand be caused to act with additional force, so as
to increase the general volume of [sound; or particular notes or passages may be
emphasized and accented by a similar triple set of pneumatic levers. As only the
three middle octaves require to be fitted with this last arrangement there are
twelve of these pneumatic levers of accent, one for every note of the same name in
the three octaves, naturals and sharps, and these levers act upon a series of
cylinders with lever arms projecting from them whereby the whole 36 notes of
the 3 octaves, may be played. In order however to enable one note in, say, the
central octave to be accentuated, without the corresponding notes in the two
adjacent octaves being also accentuated, a special set of pneumatic levers, three in
number, is provided, which may be called the "octave levers." These are
arranged on the double system, one set for each of the middle octaves. When they
are caused to collapse by the electro-magnetic and pneumatic exhaust action, they
place a series of mechanical levers in such a position as will allow of the pneumatic
levers of accent operating effectually on the strikers.
The several systeins of pneumatic levers above described are each set in action
by a current of electricity passing to an electromagnet, and they are specially
constructed with a view to prompt and silent action. Each of the sets of double

page_text: pneumatic levers already described is fitted with a delicately arranged counter-
balance weight, or its equivalent, which is caused to bear upon the long arm of the
armature lever directly the first pneumatic lever collapses, and serves, so soon as
the current ceases, to overcome the adhesion of the residual magnetism, and restore
the armature lever to its normal position. A flexible arm on the first pneumatic
lever lifts the weight from off the armature lever directly this restoration takes
place, and thus the armature is entirely free to be again attracted when the current
passes around the electro magnet. A spring may be used instead of a balance
weight to effect this result if desired. To avoid the rushing noise produced by the
exhaust on the valve passages, these are covered with chamois leather, cloth, or felt
or other porous substance.
The series consisting of triple sets of pneumatic levers differs slightly in con-
struction and arrangement from the preceding series inasmuch as they are situate
within the air passage instead of outside it, hence the valves are reversed in position.
to suit the altered position of the pneumatic levers. The armature lever is counter-
balanced in a somewhat similar manner to that above described.
The third or largest pneumatic lever is however operated by a sliding register
moved directly by one or the other of two electro magnets of opposite tendencies.
It may here be stated that each of the larger pneumatic levers of the double sets
of pneumatic levers for drawing down the strikers is fitted with reed notes and
valves by which they may be operated as desired.
It will thus be seen that the principle upon which this part of the Invention is
based consists in the multiplying of a feeble magnetic impulse by a series of
pneumatic levers of gradually increasing power, until by the last lever of the series
a comparatively powerful pull is obtained. With the view of rendering the
pneumatic action prompt the valve apertures for exhausting the air vessels
should be of larger area than those which admit the atmospheric air when the
valve is re-seated.
Mention has been made of a pneumatic pump worked by connection with the
pneumatic exhaust bellows, by which pump rotary motion is imparted to the rollers
for drawing forward the perforated sheet of music. This rotary motion also causes
the intermittent lifting of a valve of peculiar construction by which 2 pairs of air
vessels or bellows already mentioned above are alternately opened and closed to the
action of the exhaust bellows. This valve is suspended from a lever arm which is
at regular intervals raised by a tappet or projection on the rotating spindle. The
valve consists of 2 discs, the lower one being attached to a short length of cord.
The upper disc is capable of being forced down when pressure is applied to it, but
the two discs are forced apart by a spring when pressure is removed. When the
valve is raised the upper disc closes the upper orifice to the atmosphere before
the lower disc is lifted off its seat. On the valve being further raised the upper
dise is pressed with increasing firmness by the spiral spring against the upper
orifice, while the lower disc is raised from its seat and opens communication with
the exhaust.
This empties the air. vessel at one side, thereby partially rotating the wheel on
the spindle. The lever then falls, the valve seats itself, and air enters the air
vessel at the same moment that the second vessel of the pair is on the point of
being emptied by a similar operation.
The electrical apparatus consists of a Leclanché or other suitable battery from
which wires lead to a cylinder, preferably of zinc, or of a metal electro-positive
with reference to that of the fingers, of special construction and arrangement, which
rest upon the said cylinder. These fingers are preferably made of highly tempered
steel or phosphor-bronze, and are separated at their free ends. by an insulating
comb. The cylinder upon which the fingers rest is arranged so as to turn when
the music is drawn over it and frictional contact with the fingers takes place upon
a perforation coinciding with the point of a finger.
To each finger is attached a wire which is fixed firmly in the framing of this
part of the mechanism, and after being coupled to a corresponding wire on the

page_text: other side is led to the electro-magnet it is intended to operate. The fingers are
arranged in pairs to suit the peculiar construction of the perforated sheets of music
which will be now described. The sheet or web of perforated paper may be
considered as divided longitudinally into two equal parts, each half being practically
a duplicate of the other. Thus centrally there may be a space set apart for
prolonged notes, and on either side thereof will be a series of spaces for the several
notes, naturals and sharps, in an octave; outside of these spaces again will be
spaces for prolonged notes and mechanical movements.
The object of thus constructing the sheet or web of music is that the perforations
may be made of less length than usual with consequently less risk of tearing, and
care is taken that the first perforation of a note in one half overlaps slightly the
commencement of the second perforation of that note in the other half to allow of
a continuous and smooth effect being produced.
The edges of the sheets are folded down so that when two sheets are to be united
the folded portion may be cut away where the sheets overlap, and 'the single
portions left may be pasted together. There will then be a double thickness of
paper along the entire edge of the combined sheet, and this will pass smoothly
between the drawing rollers, which nip the sheets only at their edges. The sheets
rest on an adjustable bed plate or race formed of two tablets of wood or other
porous material, and fitted with two side walls of metal placed distant from each
other the exact breadth of the sheet.
The prolonged notes of the music have special fingers of their own, whereby
the electro magnets of the pneumatic levers, which have already been set in
action, may be kept supplied with electricity, and the action of the pneumatic
levers be maintained as long as the perforations occur in that part of the music set
apart for the prolonged notes.
A commutator of simple construction, and itself set in action by an electro
magnet, is provided to operate the register of the largest pneumatic levers, and
serves to direct the current, as required, to one or other of 2 electro magnets of
opposite tendencies, whereby the register is caused to slide open or to shut. This
commutator consists briefly of a cylinder fitted with a series of semicircular plates
of metal upon which rest a series of springs, one for each pair of plates. On
turning the cylinder, a different set of plates will be brought beneath the springs,
and the direction of the current will be reversed.
When it is desired to play upon the instrument by hand, a keyboard is provided.
The keys on being depressed establish electrical contact_through_the_medium_of_a_
spiral spring, preferably of conical shape. The strikers for operating the keys of
the piano may be thrown out of action wholly or in part by the elevation of certain
key stops, by which means solos, either upon the piano or the reed apparatus, may
be given, or both kinds of music may be combined.
If desired the pneumatic levers for increasing the power of the strikers may be
also caused to play upon a series of metallic plates.
It should also be remarked that the motive power which works the pneumatic
lever may be caused to work a special pair of bellows or a seperate pneumatic
lever, by which the battery may be immersed in the exciting fluid, being withdrawn
therefrom by the action of a spring.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Ford Schmoele and Alexis Mols in the Great Seal Patent
Office on the 26th January 1882.
WILLIAM FORD SCHMOËLE and ALEXIS MOLS, of Antwerp, in the Kingdom of
Belgium, Engineers. "AN ELECTRICAL MUSICAL INSTRUMENT."
This Invention relates to an instrument which may be applied to a piano to be
played by means of a keyboard of its own, or which may be played upon auto-
matically. When detached from the piano it acts as a reed instrument alone, but
whether played by hand or automatically the music of the piano may be produced
alone or be combined at pleasure with that of the reed notes; it is mainly
intended to serve the latter purpose. The apparatus may briefly be divided into
two parts, the pneumatic and the electro-magnetic. The first provides the motive
power; the second times and regulates the application of the motive power.
The passage of the electric current is determined by a sheet or web of perforated
paper or card of novel construction, which constitutes the music, and which is
drawn forward by rollers at a regulated speed. A series of metallic fingers underlies
a metallic cylinder connected with a battery, and the perforated paper is caused
to pass between the said cylinder and the ends of the metallic fingers. Whenever
a finger coincides with a perforation contact takes place, and the current of
elasticity flows to a series of electro-magnets, which instantly cause, the pneumatic
levers to operate upon a series of strikers, whereby the keys of the piano are
actuated. The Invention also relates to novel means for giving gradation of tone
to the music, for accentuating and giving expression to particular notes or passages,
and for prolonging certain sounds, as may be desired.
The pneumatic action, which may be either that of suction or pressure, is
produced by a pair bellows worked by a hand lever or by rotary motion.
In the accompanying Drawings Fig. 1 is a side elevation partly in section of an
instrument constructed according to this Invention, and operated by suction, as
being the more economical pneumatic arrangement, Fig. 2 is an inverted plan view
on an enlarged scale of the music-reading apparatus, and Fig. 3 represents a sheet
of perforated music as specially constructed for use in our instrument. Figures 4
and 4bis illustrate the apparatus for imparting rotary motion to the rollers, which
draw forward the sheet or web of perforated music, the said apparatus being
mounted in a box or casing in the interior of the instrument and communicating
with the bellows; Fig. 5 is a section on an enlarged scale of one of the electro
pneumatic trains or levers for operating the notes, a series of which levers is seen
to the left of Fig. 1; Fig. 6 is a section, also on an enlarged scale, of an electro
pneumatic resistance lever serving to lessen the initial force of one of the note
levers and two of such resistance levers are shewn in the upper part of Fig. 1;
Fig. 7 is a detached perspective view of the apparatus for accentuating particular
notes, and partly occupying the lower central part of the instrument seen in Fig. 1,
and partly situate just over the bellows E².
Figures 8 and 9 refer to parts not shown on Fig. 1. Fig. 8 represents an
electrical arrangement for holding or continuing notes which have been already
played, and Fig. 9 represents a commutator for changing the connection from one
wire to another; lastly, Fig. 10 shows a spring contact-maker for closing the circuit
situate on the underside of the key when in its playing position. Throughout these
Figures the same letters of reference indicate like or corresponding parts.
The contour of the back and front of the instrument is shewn in Fig. 1 by the
full lines of the Drawing. The dotted lines D, d, shew the position of the
cover D, D2, when the "pianista," as such instruments are termed, is placed

page_text: .
opposite a piano, its edge d' then resting on the music desk, and the entire cover
serving as a support or table to receive the sheet or web of music as it. issues from
the opening above part marked D, Fig. 1.
The dotted lines forming the triangle D, d, D³, indicate the position of a
triangular door D, D2, D3, in the side of the instrument when opened to allow a
portion of the body of the piano to be introduced within the part bounded by the
lines D, D3, D². When placed therefore in position for playing on a piano, that
part of the pianista below the line D2, D3, will be below the keyboard, and reach
nearly to the pedals of the piano, and the felted tips of the levers L will be
immediately over and almost touching the keys.
The force necessary to pull down these levers L and strike the keys is obtained
by atmospheric pressure on the several pneumatic levers p², Fig. 1, by means of an
exhaust bellows E, E³.
This bellows communicates with the horizontal wind passages E by other
vertical wind passages at the sides of the pianista, and the air of the bellows and
its air trunk is exhausted by a pair of exhaust bellows (only one of which E² is
shewn in the Drawing, Fig. 1), and which are moved by the hand lever E. It is
obvious that the bellows may be operated by any other known suitable means by
replacing the rocking motion by a rotary motion.
The strikers L, Fig. 1, are arranged in a row, and are pivotted at one end, and
free at the end overlying the keys of the piano. The strikers for the black notes
are rather longer than those for the white notes, and in their normal position are
rather higher than the strikers for the white notes. Each striker tip is felted, and
each striker of the three middle octaves has five attachinents as follows:-(1). A.
wire connecting it to its particular pneumatic lever, say, the last one p² of the
electro-pneumatic train of corresponding note and octave; (2), a wire 1 con-
necting it to a roller of corresponding note in the lower portion of the apparatus
for accentuating; (3), triple springs of resistance t', t, ts, belonging to the
pneumatic levers for diminishing the sound. The strikers not included in the
three middle octaves above named have the same attachments, except the attach-
ment corresponding to the apparatus of accentuation, which is omitted. The
object of the several combinations and their operation will be more fully described
hereafter.
The music exading apparatus shown in Fig. 2 is constructed as follows:-A
race G for the passage of the sheet of music is formed by two tablets g¹, g³, of
card, wood, or other porous substance, whose expansion under the influence_of_
damp or moisture is the same as that of paper. These tablets are held apart at a
distance some three or four times the thickness of the sheet of paper by two side
plates of metal, which plates form the walls of a channel of a breadth exactly equal
to that of the sheet of music. Metal is preferably employed for these side walls,
as it will better withstand the constant friction of the edges of the travelling
sleet. If wood be used for the tablets forming the race, transverse pieces must
be provided to prevent warping, and the boards must be unvarnished in order to
allow of the free access of air to the pores, so that the boards may swell or contract
with the paper.
At the forward end of this race G and close to the rollers H', H³, H³, is placed a
vulcanized rubber comb C attached at several points to the upper board g³ (Fig. 2),
so that it will stretch or contract in unison therewith. The spaces between the
teeth of this comb are so arranged as to correspond exactly to the columns of notes
on the passing sheet of music, and within each of these spaces is a bent metallic
finger (see 10, 20, 30, 40, &c., Fig. 2).
To attain the greatest durability these metallic fingers should be made of hard
metal, such as steel or phosphor-bronze, and the metallic surface on which their
free ends rest should be of similar metal, or preferably, of a metal such as zinc,
electro-positive with respect to the points to protect them against rust by itself
supporting the action of the atmosphere, and moreover, it should be in the form of
a movable cylinder H¹ which will allow of being easily turned and cleaned, and by

page_text: rubbing against the metallic fingers will remove all rust with which they may be
soiled. The fingers bare of wire, bent to the desired form, polished and rounded
and highly tempered at their ends. They are then ranged in order by fixing them
into holes in the transverse supporting bar A¹ previously pierced to this end at
equidistant points. This bar A is screwed at each end to the guiding plates, and
niay be so constructed as to be capable of having a tipping action imparted to it, so
as to regulate the pressure of the metallic fingers on the roller H¹. The bar A¹ is
prevented from curving inwards at the middle of its length by a strong plate of
metal A². The bar A forms the front wall of an inclosed space of which the
bar A4 forms the back wall, and between these two parallel bars are the end pieces or
blocks As. Through the bar A¹ the rear ends of the metallic fingers extend, and
they are bent up so as to extend above the level of the bar A'. When all the wire
fingers are in place, glue or other cement is poured into the trough between the
bars A¹ and A+ and allowed to harden. The bent rear ends of the fingers are thus
firmly held in a solid and compact material. Before however filling the trough
with the liquid substance, it is advisable to coat the interior with varnish to
prevent the gum or glue from soaking into and warping the wood. The parts
ought to be held firmly in a screw press during the whole operation, and until the
liquid substance has solidified. The addition of a small quantity of bichromate of
potash to the glue hastens its setting, and renders it insoluble when dry.
To the upturned end of each finger is soldered a wire, which passes tightly
through a hole in the bar A* and is led to a binding screw B where it is coupled to
a wire from the finger of a similar note, for as will be seen from Fig. 2, these
fingers are arranged in pairs. From the screws B the line wires W (Fig. 2)
and W10, W20, W30, W40, W50, and W (Fig. 8), pass to the electro magnets or to
other points. The electric current enters by a wire into the roller H₁ whence it
issues by means of the metallic fingers b whenever their points are exposed by
coinciding with a perforation in the sheet of music, and thence passes by their line
wires to the corresponding magnets, and from these latter returns to the battery by
a common return wire.
The several trains of pneumatic levers are adapted to the columns of notes in the
sheet of music arranged in duplicate, as will now be described.
The metallic finger which traverses the column c on the left is electrically
coupled to the finger which traverses the column c on the right, and similarly the
finger on the left is coupled with c on the right, d on the left with d on the
right, don the left with don the right, and so on (see Figures 2 and 3).
The object of thus arranging the notes in double columns is to avoid rendering
the paper music unduly weak by single large apertures for prolonged notes. Thus,
if it be desired to sustain a note c during 12 squares of the sheet of music instead
of a single slit 12 squares long, there would be first a hole in c on the left about
3 squares long, then another in c to the right, beginning at the 4th
square and
extending 3 square, then a third hole 31 squares long on the left hand c, and
finally a fourth hole 3 squares long on the right hand c, completing the note of
squares duration.
12
If desirable, the note may be interrupted by a very small division of paper so as
to commence the same note again; thus the holes are subdivided so as not to have
them too long, and it will be seen that the first subdivision extends rather beyond
the commencement of the second subdivision, and so on, to give an uninterrupted
note.
In the squares 13 to 18, Fig. 3 is a progressive movement of short notes placed
alternately at one side, and the other of the sheet to increase the distances between
the holes. Then in the squares 19 to 22 follows a trill movement between two
notes. Then comes a rapid vibration of the note e alone, followed by the
chord c eg, commencing at the 27th square, and sustained by the prolong-notes
to the 38th square. The metallic fingers of the prolong notes are in electrical
connection with springs i (Fig. 8) through the line W10, and can thus hold any

page_text: note which has been played and of which the spring has touched the contact
piece j, as shewn in Fig. 8.
On square 39, Fig. 3, the note e is detached from the chord ce g, the remaining
notes cg, of which are continued by the prolong notes to the end of square 48.
Finally, the columns towards the edges of the sheet are reserved for various
mechanical movements, the arrangement and operation of which will be described
further on.
To connect several sheets of music without hindering their regular motion when
passing the rollers, owing to a double thickness at the part where they are united,
the upper roller is covered with rubber at its ends only, while the lower roller is
covered throughout its length.
The edges g* (Fig. 3) of the sheet are turned back, so that the paper is double
at that point all along the sheet, but at gt where two sheets are joined this doubled
part of the border is cut away because the paper is already doubled at that part
owing to the sheets overlapping the one the other.
By this system the edges of the sheet or web present throughout a double
and uniform thickness.
The sheet issues from the drawer D, Fig. 1, and passes through the race G
and past the metallic fingers, and being drawn forwards by the rollers is led
to the exit above D. The roller H³ is geared with the rotary motor, shown in
Fig. 4, the roller H2 turns by friction only. The zinc H' on which the points of
the metallic fingers rest should be solid, or if of tubular form should be plugged
with cotton to deaden the noise caused by the points passing over the apertures
in the sheet.
At one end of this roller is a spindle or pivot by which the roller may be turned
in the opposite direction to the travel of the sheet. By placing a sheet of emery
between the rollers H2, H3, and rotating the roller H¹ in a reverse direction, the
latter roller may be thoroughly cleaned, or a strip of silk or felt H* may also rest
upon the roller, and be held against it by a spring in any convenient manner, as
shewn in the inverted view, Fig. 2.
The rotary motor is illustrated at Figures 4 and 4bis, and spindle H7, to
which rotary motion is imparted by two pairs of bellows H and H. Each pair
of bellows is coupled by a connecting rod H, and another rod H" connects it to a
-wheel H³ keyed on the spindle H7. The toothed wheel H is geared directly with
the roller H3 and causes its rotation.
One of the wheels H8 engages with an endless screw H¹³, a flyer_on_which
regulates the movement and prevents the pairs of bellows acting on the rotating
spindle by fits and starts. The whole mechanism is placed in a box, and is
connected with the pneumatic exhaust bellows. The bellows H³, H¼, are
moved through their valves 10, he (Fig. 4bis), which put them alternately in
connection with the vacuum formed inside the box H15, and with the outer air.
These valves are lowered and raised by the cams or lumps h³ on the rotating
spindle H, and in Fig. 4bis their action is apparent.
The lever h hinged at h¹ supports the valves by the wire h. The motion
of the cam lifts the lever h², which again falls by its own weight when the
cam permits it. When this lever is lowered and the valve is at rest its upper disc
76 is in contact with a stop pin h³, against which the disc is pressed by the coiled
spring h, and it is then some way below the opening h", which is open, and
allows free access of air to the inside of the bellows H by the passage H¹³. The
lower disc 10 is pressed by the air against the lower opening 12, and cuts off
communication with the air trunk E.
When the lever h² is raised by the cam ³ the upper disc 1 of the valve is
lifted until it closes the opening " before the lower disc 10 connected by the
slack cord has moved off its seat. Thus the opening his closed before the
opening his opened. The further rise of the wire and the stop pin 5 causes
the latter to pass through the opening h¹, against the sides of which the disc h° is

page_text: caught, and against which it presses more and more strongly as the coiled spring
is compressed.. At the same time the cord is tightened and lifts the disc 10 off
its seat, and puts the bellows H³ in connection with the air trunk E', which
exhausts the air and causes the bellows to collapse. This movement is com-
municated to the wheel H³, and causes the spindle to make a half rotation.
The cam of the other bellows of the pair operates the valves of the second
bellows alternately with respect to the first bellows, and causes the spindle to
complete its rotation. In like manner, the pair of bellows H10 operates on the
spindle H7, but in this case the rod from the bellows to the wheel HS is connected
at ninety degrees in advance the point of attachment of the first pair, so that
when one is in full operation the other will be passing the dead point, and
vice versa.
Fig. 5 is a side view on an enlarged scale of one of the electro pneumatic trains
for the notes seen to the left of Fig. 1. The electro magnet m attracts the
armature m³ on the short end of the lever 1, from the long arm of which depends
the first valve v' of the train. This valve is raised and lowered within the
passage o¹, and its play may be regulated by means of the screwed socket K', or
the screwed valve seat K2 When the valve is at rest it closes the air trunk E' by
atmospheric pressure, but allows the air to enter the first bellows pl. When the
armature m2 is attracted the valve v cuts off the pneumatic lever p' from the
outer air and opens it to the exhaust E, the air in p₁ is drawn out, and the lever
collapses under the atmospheric pressure. This movement is imparted by the
lever arm to the second valve v2, which in rising opens the pneumatic lever p² to
the exhaust through the channel o², and causes it to collapse.
This causes the wire ³ to pull down the striker L (Fig. 1), and sound a note on
the piano, the above movement being regulated and modified by the various
pressures simultaneously brought to bear on the striker L by the apparatus of
diminution and accentuation to be more fully described further on.
As soon as the second valve v² rises a prolongation n¹ of the arm descends.
To this arm n¹ is suspended a weight y¹ by the button n²; and at n³ is a second
button fixed above the lever arm through which passes the supporting wire of
the weight y at a distance such that the lever arm when put in movement by
the armature may move freely without touching the button n³, although coming
quite close to it.
The collapse of the lever p¹ lowers the arm n¹, so that the weight y¹ is not
upheld by it, but is carried by the button n³ on the end of the lever arm which
is then raised.
The weight y¹ is thus transferred to the lever arm and acts in opposition to
the electro-magnet m, and this opposition lasts so long as the current causes the
magnet to operate, and the lever 21 remains collapsed.
This transfer of weight to the lever arm l¹ can only take place when the magnet
has already drawn down the armature for the collapse of the lever p', and the
descent of the weight y¹ can only take place on condition, and as a result of the
previous action of the lever arm and the valve v¹. To this end the weight
descends on the lever arm just at the moment when the magnet has attracted its
armature, in which position the magnetic force is very powerful, but so soon as
the magnet loses its hold the weight is in position to restore the lever arm l' to
the horizontal position, and preferably neutralize the residual magnetism of which
there always remains some trace in the magnet after the current ceases.
In the next place having lowered the valve v' the pressure of air retains it on
its seat, and the air rushes in to the lever p¹ and by inflating it raises the arm n',
and raises the weight y¹ off the lever arm . The armature is thus free from
the counterbalancing weight and ready to act promptly at the next passage of the
current.
This alternate resistance allows the magnet to be very near to its armature
without danger of retention and greatly econoinizes the force of the battery.
If the prolonged arm n' be made of very fine spring steel, and if it be arranged

page_text: during its motion to directly bear upon the lever arm the weight y¹ may be
dispensed with. Such an arrangement is less costly than that of the weight, but
it is less exact and less economical for the battery owing to the difficulty of
procuring a great number of similar springs of uniformly equal pressure. The
perfect equality of the weights allows of the magnets being exactly adapted to
the armatures, and obviates the tendency to vibrate when a weak battery and
strong chords are used.
The pneumatic lever p¹, Fig. 5, consists of a simple disc of card or light wood
provided with a flexible covering of kid or thin india rubber, and this envelope is
held down by a card frame permanently fixed. The flexible envelope must
allow the disc to have sufficient play to raise and lower the lever arm
valve v².
and its
Fig. 6 shews a train of pneumatic levers similar to the preceding except that
the bellows are situate within the exhaust passage instead of outside it, as in Fig. 5.
Naturally therefore the valves are reversed to adapt themselves to the altered
position of the bellows.
Fig. 6 also contains a third air vessel which is not in Fig. 5, viz., the large
bellows or pneumatic lever of the third order p³, controlled by a register moved by
the second lever 22 through the bell crank lever q. Under the action of its
magnet the lever p² draws the register q² into a position the reverse of that drawn,
that is, it closes the openings which communicate with the channel q³ open
to the atmosphere, and opens the apertures q³ between the lever p³ and the
exhaust E¹.
The result is that the air of the third lever på is drawn out and the lever
collapses under atmospheric pressure from without, and by this action all thes
springs of resistance t¹, t², t³, Fig. 1, are extended between the said pneumatic levers
and the strikers L.
There is another inner electro pneumatic train belonging to this third lever of
the electro pneumatic arrangement just described but (not drawn), whose function
it is to draw the register in the opposite direction to that described above. By
means of a couple of electro pucumatic trains tending to pull in opposite directions,
the register or slide 7 will be operated, and the lever p³ will be opened or shut
accordingly.
In Fig. 6 is shewn the means for reversing a valve by a simple spring wire n¹
instead of a weight y', as in Fig. 5. The principle is however identical, and a_:
_counterbalancing-spring-wire-in-the-inside of the exhaust is desirable, as its form
is simple and it does not get out of order.
The action of the train is as follows:-
The magnet m attracts the armature m³, raises the lever arın ', closes v
and opens u', at the same time raising the button n² to touch the reversing 4
spring n¹. The air enters with force into the lever p¹, inflates it, and causes the
reversing spring n to bear upon the button_n³.
ceases.
The elasticity of the spring being about equal to the force of the weight in
Fig. 5 can not reverse the position of the valves u, v, and the lever arm while
the current is passing in m, but is in a position to do so as soon as the current
The resulting collapse of the lever lifts the spring n¹ and takes the pressure
off n, leaving the armature free to act when the current again attracts it. At the
second valve u², v², the same operation takes place on a larger scale, the spiral
spring N and button N² corresponding to n¹ and n² of the first valve. Whatever
may be the form of the counterbalance, whether weights or springs, and wherever 5
they may be placed, the principle on which they operate is always the same, and
consists, first, in the application of a temporary pressure which will tend to reverse
the position of a valve by a movement in a subsequent part of the train, so
arranged that the pressure only bears on the valve when the latter is in its active
position, and next in the relaxing of this pressure by the collapse of the pneumatic 5
lever after the valve is reversed and returned to its position of rest.
In Figures 5 and 6 will be noticed dotted lines above the secondary valves.

page_text: These lines indicate the positions of coverings of chamois leather, felt, cloth, or other
porous substances stretched across to intercept the volume of air drawn in directly
from the outside into the exhaust passage by the valve openings at the moment
these valves operate, and they serve to obviate the loud sucking noise of these
inspirations by breaking them up into innumerable little currents which pass
through these coverings without noise.
In the primary valves the openings are so small that the noise is imperceptible.
Another arrangement suitable to all the other pneumatic striking levere is
seen in the openings in the secondary valve of Fig. 5.
The motion from above downwards of the bellows p should be accomplished
more rapidly and vigorously than that in the opposite direction in order to give
a blow to the key of the piano.
The
To this end the lower opening is made larger than the opening above v².
upper opening is conical on its outer side to compensate for the resistance offered to
the air by the porous covering marked by the dotted lines.
All the electro pneumatic trains have valves arranged to close by atmospheric
pressure and hence require no springs to keep them shut when in repose, and the
principle on which they are constructed is the multiplication of a feeble magnetic
impulso by means of a series of pneumatic levers of gradually increasing power
until a relatively large power is exerted by the last pneumatic lever or bellows of
the system.
By this means the battery force necessary may be some thousand times less than
would be required for direct electrical action.
We will now describe the means for giving expression to the notes and
diminishing the otherwise mechanical and lifeless playing of the instrument.
Musical expression may be varied in several ways, such as, 1st, by change of time,
as in accelerando and retardendo; 2nd, by alteration of the value of notes, as
staccato, legato, and arpeggio; 3rd, by gradation of sound from ppp to fff;
and, 4th, by accentuation or special emphasis of the principal passage. The first
and second modes of expression may be easily obtained by properly constructing
the apertures in the sheet of music and the spaces between such apertures. The
third and fourth modes of expression are produced by the following means:-
Over the strikers L, Fig. 1, are a number of pneumatic levers of construction
similar to that shewn in Fig. 6, and called "trains of resistance," and arranged to
act on various sets of springs of different tensions which will resist the pull of the
striking bellows p² with varying force.
Each striker L is connected to three sets of such springs t¹, t, t, Fig. 1,
representing tensions of 150, 300, and 600 grammes, and each set of springs of the
same tension is controlled by a pneumatic lever p³.
The best plan of arranging the springs is to connect them to a roller and operate
this roller by the lever p³, the roller and lever being returned to their original
positions by a powerful counter spring.
Thus the sets of springs will be completely relaxed when the lever 2 is
inflated.
A set of springs of resistance comprises several octaves. The whole number of
striking levers considered with reference to the springs is divided into three
sets, each set having three co-ordinate sets of springs of different tensions so
that there are in all nine sets of springs of resistance. The first set comprises the
bass notes up to the sol (G) on the left of the central octave. The second controls
the central range of notes from the said G up to the second G, two octaves higher,
and the third the remaining notes. The purpose of this division into sets of about
the limits above named is to divide the apparatus of expression into several
sections in order to produce simultaneously and independently different effects on
different parts of the keyboard.
The trains of accent or reinforcement situate below the strikers, Fig. 1, are
opposed to the trains of resistance and are active instead of passive in the operation.
They also act separately for every note, and every time such note is repeated.

page_text: They are therefore not fitted with registers, but are like the striking pneumatic
levers in Fig. 5. They are not required in more than three octaves, say, the three
central ones.
Each pneumatic lever of accent (2³) of the train over the exhaust bellows (Fig. 1)
is connected to a roller T, by which it is put in connection with the three notes of
the same name of the three central octaves.
This connection is effected or broken by the action of the three octave bellows
3, 4, 5, of which one corresponds to each of the three octaves. These "octave
bellows" are similar in construction to the pneumatic train shewn in Fig. 6, and
are placed below the exhaust bellows and inflate and collapse inversely to the
pneumatic levers of ascent above the exhaust bellows, their object being to
determine to which of the three similar notes in the three octaves the accent is to
be imparted.
In Fig. 7 is shewn this mechanism:-The "octave bellows" 4 and 5 are in
repose; Number 3 is in action; not to confuse the Drawing, 2 accent levers only
are shewn, viz., sol represented at rest, and do in action, and having just given a
blow.
By the wire the lever do can pull on the projecting arm v² of the roller T'
which carries three other projecting arms v³, v, and 5, each of which communicates
with a lever specially allotted to itself and carried by the "octave bellows." Ench
octave bellows carries twelve similar levers, one for each note of the octave (only two
of each set of twelve levers are shewn in the Drawing). The buttons 7 and 10 do not
touch the lever do of the octave bellows 4, nor do the buttons vs and v" touch the
lever do of the octave bellows 5, because these two bellows are at rest or inflated.
The wires 10, s, and v", 14, are connected to the strikers of the keys do of the
4th and 5th octaves of the piano, but these strikers do would not give a blow
to their keys because communication is broken at 10 and v", and this because the
octave bellows 4 and 5 are not collapsed that is in action.
The octave bellows No. 3, on the contrary, is collapsed, and its lever do is
lowered with it, so as to engage with the buttons v6 and va, and it is thus that
communication is established, and the apparatus is ready to transmit an additional
or accentuating blow by 12 to the striker of the key do of the third octave of the
piano if the pneumatic lever of accent do is set in action.
The pneumatic lever sol is represented as just having_acted.-It-has transmitted
a-blow-to-S12-by-the-bar S9, S, and the arm S³ of the roller Ts which it has
partially rotated by the arm S2. But this blow could not be given either to S¹s or
to S because their octave bellows 4 and 5 are not in action.
Before the pneumatic lever of accent sol had operated, the buttons S° and S
were already in contact with their lever by the collapse of the octave bellows 3,
and were in the same position as the buttons and v in Fig. 7. The blow
therefore could take effect at this part because the buttons were already in position
to transmit it, but at S7 and S10 and also at S8 and S" they were relaxed by reason
of the position of the octave bellows 4 and 5 (as are the buttons and v¹º, and
,, and the blow of the pneumatic lever sol only caused them to come in
contact with their levers and touch them without being able to do more, and
consequently without their striking a blow. This blow was only transmitted
to S, the corresponding key of which it accentuated.
There are therefore 12 pneumatic levers of accent or re-inforcement, one for each
note in the octave, with their sharps and flats, and there are three octave bellows
for determining in which of the three octaves the accent is to be given, and as each
of these pneumatic levers of accent controls the 3 strikers of the same name in the
3 central octaves, they together control the 36 notes in the centre of the piano, do
on the left to si on the right of the central octave inclusive.
The employment of these movements in their different combinations to vary the
impulses imparted finally to the keys of the piano gives to the cords a melodius
nuance, even superior in variety to that of hand playing. Their effect is given in
a tabulated form further on. The striking pneumatic levers alone when

page_text: unhampered by springs of resistance exert a pull of some 1200 grammes; if
strengthened by the simultaneous action of an accentuating pneumatic lever
exerting a pull of 375 grammes their combined force will equal 1575 grammes. ⚫
The 3 springs of resistance combine with the striking pneumatic levers
(unassisted) to produce seven other degrees of force diminishing by 150 grammes at
a time, and they combine with the striking levers and the levers of accent to produce
seven other degrees of force, so that the gradations diminish by 75 grammes at a
time from 1275 gr. to 450 gr. Lastly, the levers of accent alone exert a pull of
375 gr., and when restrained by the resistance springs of 150 gr. or 300 gr. force
they have a power only of 225 gr. and 75 gr. respectively. Thus a gradual increase
in force of touch is attained from 75 grammes to 1275 gammes, the maximum.
Striking pneumatic lever only
Grammes.
1200
Diminished by resistance spring of 150 gr. 1050
with accent 1575.
دو
Grammes.
1425.
"
"3
"
300 gr. 900
1275.
"
- "
"
"
150+ 300
750
1125.
"
"
600
600
975.
"
"
150+ 600
450
"
"
دو
رو
"
825.
"
"
300 + 600
300
675.
"
"
150+300+ 600
150
525.
"
"
"
375.
Pneumatic levers of accent only
Diminished by resistance spring of 150 gr. 225.
"
300 gr. 75.
Thus 19 degrees of power of touch or expression are produced, allowing of a
perfect expression of crescendo and diminuendo.
Apart from the combined functions of the pneumatic levers of accent, as above
described, they have another important function to fulfil in the powerful
accentuation of single notes, and thus the theme or motive of the air can be
emphasised as required above the other notes and chords of the passage. The
means of accomplishing this will be readily understood from the foregoing
description of Fig. 7 and the parts in connection therewith.
The pneumatic levers of accent serve also to play upon a row of metal plates
arranged behind and below them on a hollow box. Each plate has a small metal
hammer with damper similar to those used in pianos, and as soon as the box is
raised to be within reach of the levers these impart motion to the hammers which
strike on the plates.
Fig. 8 shows the apparatus for sustaining the notes, and it serves, as already
mentioned, to obviate long perforations or apertures in the paper at those parts
where the cords or movements are maintained during a considerable period.
The metal finger 610 in Fig. 2 represents, for example, a note sustaining finger,
and it communicates by means of the wire W10, Fig. 8, with the series of metallic
tail pieces 20, 20, 240, 200, 200, on the corresponding pneumatic levers p20 to 20
inclusive. These tail pieces may be fixed to any other suitable part of a train of
levers. In close proximity to them are stationary terminals 0 to 60, which
communicate each with the electro magnet of the train to which it belongs.
These may also be fixed at any suitable place behind p20, for instance, as in
Fig. 8, provided it is near i, and that i when moved comes in contact with j.
When one of the levers p20, Fig. 8, for instance, collapses, the circuit is made
through 20 and 20, and so for every other train the last air vessel of which is put
in motion.
In Fig. 2 600 is the duplicate finger of 610, and it communicates with the same
wire W in Fig. 8. As soon as a chord or a note has been played which is to be
sustained without further perforations in the special columns of notes, a hole is
made in one of the columns of suspense notes passing under 610 or 6100, and thus

page_text: the electricity is conducted by what may be termed a side door to the electro
magnets, the pneumatic levers of which are in action, and these magnets and levers
can be held in action as long as the perforations continue in the prolong note
columns. This arrangement is very useful for sustaining temporarily the low
notes and for mechanical movements. Fig. 9 shews the commutator for changing
the connection of the fingers belonging to certain trains (arranged in pairs) so as
to communicate motions in alternate opposite directions as required. The register q².
Fig. 6, for instance, is moved one way by the train shown in the Drawing, and
the other way by another train of levers of similar construction.
Thus a to-and-fro movement is given to the register, and there are several such
double systems in the instrument, but to economise the number of metallic fingers
and consequently the breadth of the sheet of music, each pair of pneumatic levers
has only one finger, to which a double function is given by electrically connecting
the line wire W, Fig. 9, either to the wire X2 leading to one magnet, or to the
wire X, X², leading to the other magnet of the pair. This change is effected by
the commutator, which is a cylinder of wood or other suitable material carrying
two rows of plates opposite one another, each forming a semi circle and almost
touching each other. The ends of a row of springs rest on the cylinder, one spring
for every pair of plates, and there are as many pairs of plates as pairs of electro-
pneumatic levers having opposite functions. The plates of one row are in con-
nection with one set of magnets, and those of the other row with the other set;
consequently currents coming from a finger by the wire W, Fig. 9, are sent to one
or other of the pair of magnets according to the position of the cylinder. This is
turned in opposite directions by two trains of opposite tenderness, each of which
has a particular finger and a column of notes on the music.
The lowest bass octave and the adjacent octave share the same octave of fingers,
and are connected or disconnected at will by a coupler for each octave.
The reeds f, ƒ', f', Fig. 5, make the instrument serve as an organ, and be
musical of itself without the piano; they also permit the sound of a violin to be
imitated, and give other sustained sounds which provide an accompaniment to the
piano.
Many such series of reeds f¹, f¹, f¹, are fitted in the air trunks 0% of the pneu-
matic levers, as seen in Fig. 5, and they are regulated by the clack valves f', f³‚ƒ³,
which are opened when the reeds are playing, and shut when they are at rest.
Each series or stop of reeds is divided into sections, each section having a separate
valve, the object being to restrict the action of the reeds in passages wherein the
sound of the piano_only_is_desired,-or-vice-versa: Corresponding to the several
sections in the stop of reed notes are stops F, Fig. 1, also in sections; these are
adapted to the strikers L, and permit or restrict their movements by series
according as it is desired that the strikers should operate or rest motionless
while a solo on the reeds is being performed in one part of the instrument, and
the piano music is not required.
These stops are simply bars suspended beneath the strikers, and out of their
reach when lowered, but when raised they prevent all movement of the levers in
question which thus rest inoperative.
The electrical keyboard of the instrument for enabling it to be played by hand
is mounted on a hinged door B2, B3, Fig. 1, which when shut forms part of the
back of the instrument, and when lowered serves as the keyboard. The novelty
in its construction consists in the contact maker for its keys, one of which is
shown in Fig. 10. A. conical or spiral spring B (preferably of metal wire tapering
towards its free, end) is attached to the underside of each key, and below it is a
metallic plate h with which it makes contact gradually when the key is depressed.
The advantage of this contact-maker are noiselessness in action and a gradual
increase of pressure as the contact is more and more perfect, and an easy passage
for the current is established by W. This arrangement is superior to the ordinary
pin and bath of mercury, for it acts equally without noise, and there is nothing to

page_text: spill;
it is also superior to any arrangement of sliding springs which produce more
or less rubbing noise.
The elements of the battery are suspended from a pneumatic lever, whose move-
ment plunges them in the exciting liquid when the air is exhausted by the exhaust
bellows, and they are raised out of the liquid by a spring as soon as the pressure
on the bellows ceases. These motions are automatic. By means of a balance
valve the battery lever may be caused to vibrate and give a succession of light
shocks to the elements, which will serve to disengage the gas which accumulates
thereon; this will however not be necessary with Léclanché cells.
It will be understood that a pressure of air may be used instead of an exhaust
to work the apparatus, the valves being reversed in position.
It should also be remarked that in the exhaust apparatus there are inner pneu-
matic levers p, Fig. 6, the folds of which should be fitted with a double thickness
of stiff paper to prevent noise, while in the pressure apparatus this extra thickness
of paper is applied to the outside levers p2, Fig. 5.
The instrument above described is light and portable, it can be used as a reed
organ by means of its keyboard, or be adapted to a piano, and be played by hand
as a combined instrument. Besides these double functions it may be. used either
as an automatic pianista, that is, an instrument for playing the piano automatically,
or it may be played automatically as a reed organ, or automatically as a piano and
reed organ combined.
Having now set forth the nature of our said Invention of "An Electrical Musical
Instrument," and having explained in what manner the same may be carried into
practical effect, we wish it to be understood that we claim,―
First. An electrical musical instrument constructed in the manner and for the
purpose substantially as above described, and operated by a system of pneumatic
levers in combination with electro magnets, as set forth.
Second. The sheet of music forming part of the automatic musical instrument,
as described with reference to Figures 1, 2, and 3 of the Drawings, in which the
perforations are arranged in duplicate or triplicate columns, thereby allowing notes
or movements to be prolonged to any extent without, the necessity for long perfo-
rations in the same column, which would impair the strenth of the sheet, the
sheets being connected together when necessary in the manner and for the purpose
described.
Third. The automatic electrical music-reading apparatus constructed and operating
substantially as described with reference to Fig. 2 of the Drawing, and consisting
essentially of a series of metallic fingers separated by a non conducting comb, in
combination with a metallic cylinder capable of rotation when the sheet of music
is passing, so as to produce frictional contact with the extremities of the said
fingers.
Fourth. The employment in an automatic music-reading device such as that
described with reference to Fig. 2 of the Drawings, of a cylinder such as H¹ of a
metal electro-positive with respect to the metal of the fingers in contact therewith,
by which means the extremities of such fingers are protected against oxydation.
Fifth. In an automatic music-reading apparatus, the race for correctly directing
the sheet of music, consisting of two parallel tablets of wood or other porous
material, and two parallel side walls of metal, as described.
Sixth. The pneumatic rotary motor constructed and operating substantially
as and for the purpose described with reference to Figures 4 and 4bis of the
Drawings.
Seventh. The arrangement of branch circuits described with reference to Figures 2
and 8 of the Drawings, whereby certain notes or movements may be prolonged or
sustained as long as required.
Eighth. The commutator for a musical instrument consisting of a double row of
metallic plates mounted on a non conducting cylinder, substantially as and for the
purpose described with reference to Fig. 9 of the Drawings.
Ninth. The combination of an electro magnet with a series of pneumatic levers,

page_text: in which each successive lever and its valve are of greater capacity than the
preceding lever and valve by which they are operated, the first lever in the said
series being operated by the electro magnet.
Tenth. The valve without a spring placed in the channel which leads to the
bellows, the said valve acting against the air pressure when the pneumatic train is
in action, and with the air pressure without a spring when the train assumes
a position of repose, substantially as described with reference to Figs. 5 & 6 of
the Drawings.
Eleventh. The construction and arrangement of electro pneumatic lever described
with reference to Fig. 5 of the Drawings.
Twelfth. The construction and arrangement of electro pneumatic lever described
with reference to Fig. 6 of the Drawings.
Thirteenth. The application to electro pneumatic levers of the automatic
temporary counterbalance consisting of a spring or counter-weight which is
brought into the operative position by a movement of a part of the train
subsequent to the motion of the valve which it tends to reverse, and is thrown
out of action by the movement of the train in assuming a position of repose,
as set forth.
Fourteenth. The means for diminishing the blow of the strikers L, consisting
essentially of a series of electro pneumatic levers and springs of different tension
in connection with said strikers, substantially as described.
Fifteenth. The arrangement of mechanism for strengthening the blow of the
strikers L, and thereby enabling certain notes and passages to be emphasized,
substantially as described with reference to Fig. 7 of the Drawings, such mechanism
being also adapted to operate on a series of inetal plates to produce the effect of
cymbals.
Sixteenth. The combination of electro pneumatic levers for producing a wide
range of effects of crescendo and diminuendo, substantially as described with
reference to Figures 1 and 7 of the Drawings.
Seventeenth. The application of reeds to the air pressure or exhaust passages of
the last pneumatic lever in an electro pneumatic train, in the manner and for the
purpose described with reference to Figures 1 and 5 of the Drawings.
Eighteenth. The means described for arresting at will the movements of the
strikers L, and for allowing the reed notes to sound, thus enabling either-reed-
notes or piano notes to-be-sounded-on-certain sections of the instrument.
Nineteenth. A spiral or conical spring contact maker (preferably constructed of
wire, decreasing in thickness towards its free end) for the keys of electrical musical
keyboard instruments, substantially as and for the purpose described with reference
to Figures 1 and 10 of the Drawings.
Twentieth. Immersing the elements of a battery in the exciting fluid and
withdrawing them therefrom by the alternate movements of a pair of bellows
assisted by a spring in an electro pneumatic musical instrument, for the purpose
specified.
In witness whereof, I, the said Alexis Mols, have hereunto set my hand
and seal, the Twenty third day of January, in the year of our Lord One
1