The musician of Jaquet-Droz

--- translation by Julie S. Porter

From the work Le monde des automates by Alfred Chapuis and Edward Gelis. this two volume quarto covers the entire history of automata, which does not have an exact english equivilent. Robots and simulated life are perhaps the best we can do. Only one thousand copies of this rare book were printed in 1928. According to the frontpiece the first twenty five were reserved for the emperor of Japan. The book can however be located in the medical libraries of most major univerities. It is filed under the subject heading 'Artifical limbs'. It is most likely to be found in the library of an orthopedic surgen.

Professor Chapius died in 1958. Only two of his over 40 volumes were translated into english, unfortunatly it would take an army of translators to do Le Monde des automates justice. There have been inferior copies reprinted of this title over the last few decades. Unfortunatly the quality of the cuts was simular to that of my xerox. The original was lithograped onto smooth paper the cuts having a fine screen that can not be easly reproduced. I was told verbably that the plates were destroyed during WWII along with some of the articals illustrated. (fortunatly the Jaquet-Droz dolls still exist) A number of the items described were from the David Solomins collection, which was stolen and has never been recovered shortly after beeing placed into a museum in Isreal.

This is my own translation. I reserve all rights to its beeing used for profit or included in compilations. Links to it of course are most welcome. I am not at all sure about the status of the origional document. Professior Chapius was an educator and wrote many articals for magazines such as Hobbies, American Horologer and jewler, NAWCC Bulitin, and the BHI journal.I have the impression from these writings that he was against the secretive nature that lost the watch industry to disposable products. He appears to have been a self appointed spokesperson for swiss horology. He usually used a technical collaborator. I have been told that the major orginisations such as MBSI, BHI, and the NAWCC were given in writing permission to translate and reprint any of professor Chapius works. I have not verrified this. although I have seen something simular on MBSI translations.

Here then is my translation of Pages 270 through pages 277. I make no claims on the accuracy, and take no responsibility for any resulting use.

With the musician Jaquet-Droz; of we come to find the most beautiful android of those which make up this chapter. The designers of this automaton recall finishing it in 1773 at the same time as the draftsman and the Grotto. The document which we have already given some extract[1] indicates what the state of advancement it was in as of September of 1772. Jean-Frédéric Leschott;, the collaborator of Jaquet-Droz; wrote: "The figure appears to play on an organ or a harpsichord; At this time she does not have her hinged fingertips or the middle of her back. The arm supports are attached to a wheel that is carried on pointed cylinder without levers and the cams are not finished. The movement of the head, the eyes, and the throat still did not exist until after a gap in the transmission of their mechanism. What to assure as much is that M. Henry Jaquet-Droz; had a certain Mathiaté [Matiatek]; make the flutes and valves for the aforementioned action inside beginning of the month of November 1772." We see therefore how quickly the musician was completed. The document is not precise in the indication of whether the original android played the organ or harpsichord. This point, which has been debated for a longtime is clear today by what now exists. The flutes, bellows, and valves are in effect parts of an organ, not a harpsichord. Fig 513 shows the appearance of this android about 1780.

The mechanism of the musician of Jaquet-Droz; (with the collaboration of M. H. Wanner).

Jaquet-Droz; and their collaborator Leschot gave the musician the appearance of a young girl who's grace and charm pleases the spectator with the tune that she plays. Sitting in front of her instrument, her fingers rest agile upon the keyboard. She appears natural in her music. Her attitudes show in every gesture. Testing her emotion before the public, who hear her breathing, she turns her head right and left as she looks over her audience. She executes with precision the piece as she seems to follow attentively the music positioned upon the music stand. fig 514 Now ready to play her body bends over lightly, as if to read the notes more closely. She performs a pavane; or a delicate melody so different of the past. We follow with wonder her amiable concert, too soon accomplished. The gracious artist raises her chest, then sensitive to the divine compliments she performs a perfect bow. Afterwards she glances over the assembly to make sure of her success. While we commit to a request for a new hearing.

In reality it is the inventor we applaud. It is his delightful interpretation that makes us forget for an instant, because she is a real beauty, the wonder that this life is not that of an insensible mechanism. What an ingenious mechanism to combine clothing an construction! We will now study the details with precision. The reader, after following the numbers and functions of the gears and levers, will be judiciously prepared to see that the way to the beauty of this android. The transfer of the harmony from the outside to the action of her operation.

The musician of Jaquet-Droz; is an attractive set which measures 1.80 meters high, 66 centimeters wide and 85 centimeters deep. The keyboard of her instrument is 40 centimeters long and contains 24 keys.

A thick base of wood serves to support the pieces of the machine where the four clockwork movements are found. These moments are interrelated and command each other. First study the bellows motor which is represented in figure 515. The reader will not forget that it is the fingers of the musician which play by effectively pressing on the individual keys on the keyboard as in a real instrument. It is necessary then to have a producer of wind. Also needed is the valve controlled by the keys to steer this wind to the appropriate pipe.

The bellows are very powerful. Jaquet-Droz; probably did not arrange for a spring sufficiently strong. The two barrels (B) fig. 515 were used instead of one. We see wrapped around the barrels the two chains (e) which join the barrels to the fusees (E). The axle (C4) rewinds through a pinion (c) which engages wheel (d5). The axle of wheel (d5) is common to the two fusees. One wheel on the Fusses (E) (the one on the left in the figure) commands the train to engage the last wheel which is attached to crank (F1). This action impulses connecting rod (f5) which is connected to lever (g). Lever (g) is fixed to shaft (h) which passes to the other side (hidden on the figure) two branches (one of which is visible as (i2)) activate in turn, the bellows. We see how the speed of operation is regulated by fan (H) which is controlled by an endless screw (G). The lever (I1) stops or frees the rotation of the fan. This is the only device for producing the wind. The feet of the automaton are not articulated. They do not provide action to the bellows.

Now passing to the completed movement, which has been withdrawn from the chair in which it rests. fig 516 and 517 show two different views of this mechanism. All at once we can see how the rest of the action is carried out since we have seen how the wind is produced. To simplify the confusing appearance of the parts (confusing in appearance yet methodically tidy in function) the following description should shed a little light.

Between the plates (A) fig 516 is mounted cylinder (C) of which the pins and the cams command the action of the musician. (section 1). In the back (in the first plan of the figure) between plates (L) is the mechanism for moving the head and respiration. (section 2) Finally underneath the principal mechanism is an independent unit which preforms the curtsy (section 3)

Now we isolate the part of the mechanism that commands the action, strictly speaking, the movement of the fingers. fig 516. The cylinder (C) turns between plates (A). It is made of four parts (C1,C2,C3,C1) the region (C1) we see is pitted with pins and bridges. This controls the fingers through the intermediate levers (D5). which are raised as the points pass below.

A delicate point is here. It is necessary to to transmit the action of the levers (D5) to the fingers which are situated far from the cylinder. Jaquet-Droz; worked out an ingenious and rather simple solution. In place of making the commands pass through the longer arm from the shoulder they chose the short path. The junction of the arm at the elbow of the musician. The body itself then does not contribute to these movements. When the automaton is dressed you do not perceive in the least her fault.

We see in (E1) the acting transmissions at the elbow. The repeating wires which are assigned by the levers of the fingers (e1) fig 517. The forearms are mounted upon shaft (F) which pivots about (f). This is able to effect the lateral movement, which is controlled by the cams (C2). These cams control levers (f3) which press against the levers (f2) on the shafts (F) and are held in check by the long springs (f1). Notice the regulation screws (f4) which permit the placement of the fingers exactly above the keyboard.

If the audience wishes to here a piece over the tune can be selected at will. Otherwise it will play automatically. This is done in the following way. At the extreme right of the cylinder fig 516 is a lever (D). This acts upon a star (D1) which is supported by rod (D2). At the extreme opposite of this rod is attached lever (D8). A second arm of lever (D8) is engaged by a projection on the axle of cylinder (C). The tune is started by the lever (D3) fig 517. This caries the piece (D4) fig 516 which is tied to lever (D). These rest immobile and the piece will be repeated since the star attached to (D1) is not released. If we turn the lever (D3) the opposite direction this activates (D4), (D) and (D1). The star, allowed to be released, will change the tune once each turn. This is due to the action of lever (D8). The cylinder C slides on its axle. The pins and bridges line up with the followers to produce the selected tune.

Now that we know how the music is produced we will study, in the course of a performance, the operation of the musicians movement. One of the more interesting is the movement of the head which turns right and left. Its gestures are given much expression by the movement of her eyes. In (O) fig 516 is a cut cam which articulates a lever (o) and follower (o1). This acts on the connecting rod and lever (o2). When the principle mechanism is stopped the musician does not turn her head. After the song the piece (o3) coupled to the lever (g1) which we see is articulated with piece (g2) and articulated with piece (g3) which is mounted on arbor (g4). Now the impulse to the right an left movement of the head can be understood.

At the side of the mechanism fig 516 we see a series of interdependent items, which we have not spoken about. This is the mechanism for creating the gracious bow to the audience. We see in (H1) the barrel and winding square (h1). If we look for an instant at fig 517 we see a tab(d2). At the end of the completed turn of cylinder (C) it engages lever assembly (d1). The connecting rod (I) is fixed to (d1). The shaft (i) is attached at a right angle to this assembly. fig 516. transmits its movement to bent lever (i1) a branch which is passed through the bottom plate to the release mechanism on barrel (H1). The release mechanism produces the reverence when lever (J) is lifted up to permit the long branch (j) to shift the wheel following the cam. The upper body is made to incline by the intermediate connecting rods (K) and the piece (k1)

Before the performance the public is particularly stricken by the apparent respiration of the artist. A doctor one day remarked "What an observer was Jaquet-Droz;!, his musician breaths as a woman, high and low". Nothing is neglected in effect or the perfect illusion of reality. To the rear of the principle mechanism fig 516 the "Life Mechanism " is contained between the plates L. The barrel (l) is connected to a fusee of which the rewinding square (l1) is visible. A small wheel M commands the regulation fan (m) on an endless screw. A crank controlled by this, activates lever (n) which is lifted once each turn by an eccentric (not visible in image). This eccentric determines the rate of respiration. The connecting rod (n1) is connected in the back to vertical transmission (n3). This activates the reversing lever of the square (n4). The breasts are lifted and pivoted in alternating motion via (n2) which is activated by (n).

What is left now is to give the eyes mobility; then this gracious lady will have every physical characteristic of life. Two hooks (P) fig 516 , which push in when the principal stops (at the end of the passage and during the reverence) enter into contact with the rods (r). These rods activate connecting rods (r1) which assign rotation to these bent levers (r2). These levers pull the transmission which handles the lateral and vertical movement of the eyes. As soon as the principle mechanism restarts. the hooks (P) are pulled out. this returns the motion to the large cams on cylinder (C), which, fulfill their duty and the automaton reads her music.

The united mechanism is pure in conception as the multiple parts occupy a reduced space. The photographic reproduction does not give the clarity of detail that we could wish for. We hope however that our essay of the description and methodical analysis of the movements has given a measure of the ingenuity which was deployed by the Jaquet- Droz;. Now we know the secrets disseminated this hour the grand costume of this friendly musician. Having dressed again of her attire, return for an instant our attention to the wheels and levers to know how to give life to these moments which are ready to function. First turn Bolt (N) fig 516. This releases the mechanism of life. The cam (O) creates movement of the head. The hooks (P) render the eyes mobile. Put the bellows into motion and push lever R fig 517. This frees the lever (d1). The fan (d4) is freed. The cylinder C turns which lifts the levers (D5) fig 516 which activate the fingers. When we desire to grant a moment of rest to the artist we bring back the lever R fig 517 to its first position. (d1) pulls out of its notch stopping the mechanism.

Translation © 1996 Julie S. Porter

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