Scientific instruments

Sextant

Sailors have always navigated by observing the heavens. By measuring the height of the sun, stars or planets above the horizon they could determine their position. In the 15th century mariners used quarter circles with two mirrors situating the celestial body observed in relation to the horizon line.

Reflection circle

The calculation of longitudes, indispensable for determining a ship’s exact position at sea, was not possible until the octant’s invention in the 18th century, though it lacked sufficient precision. The French mathematician Charles de Borda finally solved this problem by inventing the reflection circle.

The Sigma telescope

The SIGMA coded mask telescope project, begun in 1981, was one of the key components of the French gamma-ray* astronomy programme. The aim of this project was to observe astronomical phenomena that traditional reflecting telescopes cannot reveal.

Pile of weights weighing 50 marcs, known as ‘Charlemagne’s pile’

The museum has ‘Charlemagne’s pile’, a copy of an ancient set of weights now lost. The weights are piled on top of each other and weigh a total of 50 marcs (slightly more than 12 kilograms).

Standard metre

To put an end to the multiplicity of weights and measures units, France’s revolutionary government decided to create a universal system. On 26 March 1791 the Constituent Assembly adopted the proposal made by the Académie des Sciences, creating the metre, equal to one ten-millionth of the distance from the Earth’s equator to the North Pole. Two astronomers, Jean-Baptiste Delambre and Pierre Méchain, were charged with measuring this imaginary line representing a quarter of the Earth’s meridian.

Equatorial sundial

Sundials were among the first devices created to tell the time. The variation of the shadow cast by a pin or blade (the gnomon or style) on a graduated surface charts the Earth’s rotation on its axis, and therefore solar time. The dial indicates solar noon, the moment when the sun is highest in the sky.

Meridian cannon

At the end of the 18th century the Parisian clockmaker Rousseau devised a ‘meridian cannon’ with a lens that focuses the sun’s rays when it is at its zenith, igniting powder whose detonation tells local residents that it is midday. This meridian cannon is a scaled-down replica of the one that has graced the gardens of the Palais-Royal in Paris since 1786.

Water clock

In the late 1660s, the architect and doctor Claude Perrault devised a genuine clock whose mechanisms are driven by the flow of water. The flow of liquid in a waterwheel works cogs and the clock can even chime. But all these devices lacked precision, and as mechanisms were gradually perfected and miniaturised they were soon replaced by spring-driven clocks.

Astronomical longcase clock

The particularity of this longcase clock is that it beats the seconds and serves as a reference to adjust other clocks. It indicates the hours and minutes separately on the two small dials within the large double dial.

Doubled-sided watch with grand complications no. 92

Born in Neuchâtel in Switzerland, Abraham Louis Breguet made exceptionally crafted clocks, chronometers and watches. Seeking precision, he perfected watch and clock movements and invented new escapements. Breguet’s watches with complications were hugely successful at European courts, and Queen Marie Antoinette’s patronage did much to increase his renown. He also supplied Emperor Napoleon I and the Queen of Naples, Caroline Murat, for whom he created the first wristwatch around 1810.

Clock with annular dials

This double-dial clock was intended to be placed on a piece of furniture or a mantelpiece. Its ‘annular dials’ arrangement is original: the hour and minutes are not indicated by hands moving on a circular dial but by the rotation of two rings with the numbers painted on them.

Longitude clock no. 24

In the 1730s, nautical clocks joined these navigation instruments. On departure, the marine clock is set to the time. By measuring the difference between the time indicated on this clock and the time ‘observed’ (for example with a sundial), sailors could determine the longitude and thus calculate their precise position at sea.

Tide clock

Antide Janvier was a pioneer, renowned for his clocks with astronomical spheres. Clockmaker to the king, in 1786 he proposed the construction of a large clock indicating the times of the tides all over the world.

Mystery clock

Appearing in the mid-18th century, ‘mystery clocks’ were designed to indicate the time but also to fascinate and surprise. Making full use of ornamental sculpture, their makers devised ingenious subterfuges to conceal their workings. Like the one on display in the Musée des Arts et Métiers, awarded a prize at the 1889 Universal Exposition, mystery clocks were often mechanical masterpieces in their own right.

Pneumatic clock

To dispense with winding clocks, a source of malfunction, Charles Bourdon devised an ingenious mechanism powered by a ‘hydro-pneumatic’ motor.

Electric master clock

It was in his workshop in New Orleans that the French clockmaker Stanislas Fournier became interested in the use of electricity in horology. Winner of the Grand Prix for mechanical clockmaking at the 1867 Universal Exposition in Paris, he designed electric clocks and clock chimes.

Thermometer and barometer

Thermometers and barometers were two of the instruments usually found in physics cabinets. They use the dilatation of liquids to measure temperature and atmospheric pressure. Antoine Assier-Perricat and André Bourbon, both instrument makers, were renowned for the precision of their apparatuses and the quality of their blown-glass tubes.

Large reflector mirror

Reflector mirrors, known since Antiquity, had pride of place in galleries and cabinets of curiosities from the 17th century onwards. By concentrating the sun’s rays, they enable experiments requiring extremely high temperatures, such as the vitrification of earth or the melting metals and stones.

Lavoisier's laboratory

Antoine Laurent de Lavoisier is regarded as the father of modern chemistry. His experiments leading to the identification of oxygen, the law of the conservation of mass (‘nothing is lost, nothing is created, everything is transformed’) and the synthesis of water were landmarks in the history of chemistry.

Leyden jar in a vacuum bell, or ‘luminous matras’

The Leyden jar can be regarded as the first electrical capacitor because it accumulates electricity and produces a charge. The Dutch scientist Pieter van Musschenbroek conceived the first jars in Leyden in 1745. The following year the French physicist Nollet demonstrated the invention to Louis XV by electrifying a chain of 180 royal guards in the Hall of Mirrors at Versailles.

Composite microscope

The microscope contributed to the scientific revolution of the 16th century by enabling the observation of the infinitely small. This beautiful and remarkably finely crafted instrument belonged to Michel Ferdinand d’Albert d’Ailly, Duke of Chaulnes.

Monochord with keyboard

The German piano and harpsichord maker Jean Tobie Schmidt (Johann Tobias Schmidt) made this monochord with keyboard. Based in Paris from the early years of the French Revolution, Schmidt became known for, amongst other things, perfecting the guillotine, used extensively from 1792 to 1795.

Aeolipile on a chariot

The aeolipile is a pneumatic machine whose invention is attributed to the Greek mathematician Hero of Alexandria in the 1st century. By heating water in a metallic sphere with two tubes, Hero produced steam whose escape made the sphere spin.

Robertson-type slide rule

This large slide rule, listed in the Conservatoire’s collections in 1853, is of the kind invented by the Englishman John Robertson, director of the Royal Naval Academy in Portsmouth. An improvement of the logarithmic slide rule devised by the London-based mathematician Edmund Gunter and furthering Napier’s work on logarithms, this wood and brass slide rule has several fixed scales and a sliding scale, a screw adjustment mechanism and a cursor.

Circular multiplication machine

The inventor of this calculating machine, the Hungarian Jewish doctor David Roth, immigrated to France, where he practised homeopathy for thirty years, treating wealthy Parisian patients. Roth’s mechanisms are based on the principle of their successive transmission: unlike the Pascaline, the number of wheels and therefore the size of numbers is no longer limited by the user’s manual strength.

Hyperboloid with one surface

Founder of the École Centrale des Arts et Manufactures in 1829 and a teacher at the Conservatoire des Arts et Métiers, Olivier commissioned the mathematical instrument maker Hippolyte Pixii to construct articulated geometric models representing a series of surfaces and their modifications. The model on display visualises a cylinder’s transformation into a cone: the rotation of the upper circle creates a hyperboloid out of the two volumes.

Repeating circle

In the mid-1780s Charles de Borda made several improvements to geodetic instruments for measuring the distance between two points. He devised a repeating circle based on the principle of measurement by triangulation, enabling the determination of a distance no longer by measuring the terrain, but by considering the angles formed by elevated reference points (church towers, castles, trees).

Microscope, crank winder and gyroscope

This instrument works on the same principle as a spinning top: a rotor (a bronze disc with a bulbous rim) is set in motion using a crank mechanism. Due to its very high rotation speed (between 150 and 200 revolutions/second), the rotor is freed from the constraints of gravity for ten to fifteen minutes. Thus it is enough to measure, with a needle or a microscope, the slow rotation of the gimbal (ring) surrounding the rotor to see the rotation of the Earth.

Apparatus for measuring the speed of light

François Arago’s work on the speed of light was pursued by Léon Foucault at the Paris Observatory. His experiment consisted in passing a beam of light through a micrometric target composed of vertical lines 1/10th of a millimetre apart. The rays were then reflected in a mirror turning at 400 revolutions/minute, then, successively, in four static mirrors.

Multi-wire proportional chamber

From the early 20th century onwards, a number of experimental apparatuses were developed by physicists to detect new particles. The principle of these apparatuses is to observe not the object itself but the trace it leaves in its path. In 1912 the Wilson cloud chamber enabled the trace of particles to be followed by the ionisation* of a gas.

Model OM1 X-ray tube

Late in 1895 the German physicist Wilhelm Röntgen, conducting experiments on electrical discharges in rarefied gases in a Crookes tube, revealed the existence of an unknown radiation that he called ‘X-rays’. When he placed his hand between the tube and a screen, he saw that only his bones and not the less dense parts of his hand were visible. Doctors rapidly began using these new rays to observe sick organs and detect foreign bodies such as bullets.

Elmiskop 102 transmission electron microscope

The French National Institute of Health and Medical Research acquired this electron microscope in 1973 to study cancer-causing viruses.

Hilare autonomous mobile robot

The Hilare robot was designed in 1977 at the LAAS (Laboratory of Analysis and Architecture of Systems) in Toulouse. It is regarded as the first French mobile robot capable of autonomously negotiating an unknown environment.

Lama rover

Designed for the exploration and cartography of Mars, the Lama has a prototype chassis developed by the Russian space programme. The result of collaboration between Alcatel Espace and LAAS for the instruments, this robot can autonomously decide on its movements thanks to its capacity to perceive and map its environment.