Jean-Frédéric Leschot and orthopaedics - The website of automatons, automata and androids.

Along with constructing androids, automaton clocks and mechanical birds, the Jaquet-Drozes and their partner Jean Frédéric Leschot took to making prostheses which skilfully replaced amputed limbs. Jean-Frédéric Leschot specialized in this activity. His reputation in this field brought him numerous orders from many foreign countries.

Jean-Frédéric Leschot is the creator of numerous active prostheses - The website of automatons, automata and androids.
Jean-Frédéric Leschot
We must admit that he took advantage of his watchmaking knowledge to make active prostheses whereas the best doctors of that time used to make passive prostheses. These were made only for an aesthetic purpose whereas Leschot's prostheses allowed usual objects to be seized and manipulated in a way that no one knew that they existed. (In the film "The Jaquet-Drozes' androids — on sale on this website—a prosthesis is reassembled according to the descriptions given by Jean - Frédéric Leschot.)
Chapuis and Gellis, the authors of Le Monde des automates (The world of the automatons) wrote: "We reproduced a note from the 1792 Newspaper of watchmaking detailing the different parts of an artificial arm according to gravity. It is an interesting document for it presents the materials used, the accuracy of each organ's weight" :
(French measures of that time)
The elbow joint with all its steel parts
2 onces 8 deniers 18 grams
Leather covering the stump from the shoulder to the elbow joint.
4 on. 10 den. 18 grs.
The wrist joint including the steel trigger part fixed at the joint with the wire link.
18 den.
The arm made of cardboard and parchment from the elbow to the wrist joint.
3 on. 22 den. 5 grs.
The cork wrist with spring and cylinder as well as the finger-bearer anchored to the wrist.
2 on. 4 den. 15 grs.
The whole thumb with steel strips anchored inside for both joints.
17 den. 4 grs.
The finger, mounted the same way with all the parts and the nut.
10 den. 21grs.
The middle finger, mounted as above.
14 den. 3 grs.
The ring finger, mounted as above.
9 den. 16 grs.
The little finger, mounted as above
7 den. 15 grs.
16 on. 3 den. 19 grs.
The writer's hands created by theJaquet-Droz family - The website of automatons, automata and androids.
The writer's hands
The weight of the artificial arm was about 480 grams. It is obvious that this prosthesis had to be well studied in order to be that light.
The draftsman's hands created by the Jaquet-Droz family - The website of automatons, automata and androids.
The draftsman's hands

Finally we must demonstrate how the clockmaking techniques allowed J.F. Leschot to make such functional prostheses and artificial limbs.

In their book The Jaquet-Drozes and Leschot, Charles Perregaux and F.-Louis Perrot wrote:

"In a letter addressed to Mr de Luze-Bethmann in 1795, Leschot explained the mechanism of the wooden and iron limbs for Mr de Luze had ordered a left arm for the Baroness Strakham from Frankfurt. Leschot replied: "I am in a position to fulfill your request. Many items of this kind have already been entrusted to me by people who were always satisfied and relieved. A few years ago I made an artificial arm for a young lady whose arm had been amputed almost up to the shoulder and it is very useful to her and nothing shows when she is dressed."

Arm prosthesis made by Ambroise Paré - The website of automatons, automata and androids.
Arm prosthesis made by Ambroise Paré
Then Leschot asked that a mold of the Baroness'right arm and hand be sent to him. On this model the size and "embankment" of the amputation had to be written. The stump shape thus known, Leschot was able to drive and adapt the artificial limb to it.

According to Leschot, the mechanism which is very mobile at the elbow joint as well as the other parts allowing the following functions shall be so well fixed that the artificial arm shall obey the lady's will of movement. And about the right hand, he let us also know that:

"In the hollow of the mechanical hand I have installed a trigger hidden in a glove that she always must have and which is easy to change. When she slightly pulls the trigger with the right hand's palm, the elbow hinge releases, which enables her to raise or pull down the artificial arm from its former position and in a fixed way at the required level of any desired movement."

Artificial arm by Kriegeissein - The website of automatons, automata and androids.
Artificial arm by Kriegeissein
"Then, she rotates the arm from left to right as well as the wrist, that is to say the hand which moves around the joint, giving the required attitude to the arm. The fingers have three joints too which can move separately in the case that she wants to hold something in this hand, giving them a natural driving to held such a thing. It is to notice that only the thumb has a pressure power against the second finger, it is thus used to pinch or seize light or small objects such as a card, a knitting needle, and so on...

The elbow joint is particularly useful in winter for instance when one has a muff. Such objects could be held while the right arm would be free or used for any other object or movement..."

Such an artificial limb cost 50 Louis.

Left hand of the female musician by the Jaquet-Drozes

The artificial hand of the female musician by the Jaquet-Drozes - The website of automatons, automata and androids.

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