Jacques-Barthélemy Micheli du Crest
Encyclopedia
Jacques-Barthélemy Micheli du Crest (September 28, 1690 – March 29, 1766) was a Geneva
n military engineer, physicist and cartographer. Born into the aristocracy, he eventually fled to France as an enemy of Geneva and eventually spent his later years in Aarburg Castle
as a political prisoner. During his time there, he mapped the Alps
accurately using rudimentary tools. One of his other major accomplishments whilst in exile was to create a thermometer and a temperature scale, which was commonly used in Switzerland and around Europe until it became obsolete in the 19th century.
and was an outspoken critic of the planned wall around Geneva. Eventually, due to his views and publishing pamphlets such as "Maxims of a Republican", he was declared an enemy of Geneva, his rights as a citizen were revoked, his lands were confiscated and he was sentenced to death. Du Crest fled to France in 1730, and an effigy
was symbolically beheaded in 1735.
, where he was arrested in 1746. He was moved to Aarburg Castle
, after getting involved with Samuel Henzi's conspiracy, where he was held as a political prisoner for the remainder of his life.
, and the temperature of boiling water as a second fixed point. His scale between these points was then divided into one hundred equal degrees.
he published many meteorological papers and created a cartographical drawing of the Alps as viewed from the castle. Without any modern equipment, such as a theodolite
or telescope
he instead used an eight-meter long gutter pipe, filled with water to measure levels and a small rod held in front of it, he could measure the heights of the peaks. He then used the Scheuchzer map of 1712 to calculate the distances away, and drew the first scientific panorama of the Alps.
Geneva
Geneva In the national languages of Switzerland the city is known as Genf , Ginevra and Genevra is the second-most-populous city in Switzerland and is the most populous city of Romandie, the French-speaking part of Switzerland...
n military engineer, physicist and cartographer. Born into the aristocracy, he eventually fled to France as an enemy of Geneva and eventually spent his later years in Aarburg Castle
Aarburg Castle
Aarburg Castle is a castle in the municipality of Aarburg in the canton of Aargau in Switzerland. It is located high above the Aarburg on a steep, rocky hillside. The castle was built around a medieval castle, which controlled the narrow point on the Aare river and served as the seat of Aarburg...
as a political prisoner. During his time there, he mapped the Alps
Alps
The Alps is one of the great mountain range systems of Europe, stretching from Austria and Slovenia in the east through Italy, Switzerland, Liechtenstein and Germany to France in the west....
accurately using rudimentary tools. One of his other major accomplishments whilst in exile was to create a thermometer and a temperature scale, which was commonly used in Switzerland and around Europe until it became obsolete in the 19th century.
Life before exile
Du Crest was born into the aristocracy, and during a period in the military he became a Captain and military engineer by the age of 23. In 1721, after leaving the army, he took up his place as a member of the Genevan parliament, as was his family's right, specialising in security. During his time in the parliament, Du Crest argued against the Genevan oligarchyOligarchy
Oligarchy is a form of power structure in which power effectively rests with an elite class distinguished by royalty, wealth, family ties, commercial, and/or military legitimacy...
and was an outspoken critic of the planned wall around Geneva. Eventually, due to his views and publishing pamphlets such as "Maxims of a Republican", he was declared an enemy of Geneva, his rights as a citizen were revoked, his lands were confiscated and he was sentenced to death. Du Crest fled to France in 1730, and an effigy
Effigy
An effigy is a representation of a person, especially in the form of sculpture or some other three-dimensional form.The term is usually associated with full-length figures of a deceased person depicted in stone or wood on church monuments. These most often lie supine with hands together in prayer,...
was symbolically beheaded in 1735.
Life in exile and as a political prisoner
Whilst in France, Du Crest spent much of his time dedicated to scientific study. He made advances in the study of temperature and came up with a recognised temperature scale which was used in Switzerland for many years. Du Crest was still outspoken regarding political issues, and lost the support of the people protecting him in France. He was forced to flee again across Europe in 1744, stopping in major cities such as Zurich and Bern, until he became ill and was hospitalised in Bern's InselspitalInselspital
The Inselspital , officially the Bern University Hospital, is the university hospital of Berne, Switzerland, and one of the country's leading hospitals....
, where he was arrested in 1746. He was moved to Aarburg Castle
Aarburg Castle
Aarburg Castle is a castle in the municipality of Aarburg in the canton of Aargau in Switzerland. It is located high above the Aarburg on a steep, rocky hillside. The castle was built around a medieval castle, which controlled the narrow point on the Aare river and served as the seat of Aarburg...
, after getting involved with Samuel Henzi's conspiracy, where he was held as a political prisoner for the remainder of his life.
Scientific achievements
Du Crest devoted a significant portion of his life in exile to scientific study, making pioneering developments in cartography and the measurement of temperature.Temperature scale
Du Crest believed that the temperature of the Earth was fundamentally fixed, based on the supposition that cellars and mines maintained an equal temperature. He used this "temperature of the terrestrial globe" as one fixed point, measured in a cellar 84 feet (25.6 m) below Paris ObservatoryParis Observatory
The Paris Observatory is the foremost astronomical observatory of France, and one of the largest astronomical centres in the world...
, and the temperature of boiling water as a second fixed point. His scale between these points was then divided into one hundred equal degrees.
Thermometer
Du Crest rejected mercury thermometers, stating that the substance was too difficult to purify, preferring instead alcohol which had passed the gunpowder test. He created a thermometer based the expansion of alcohol, calibrated using mercury. He further published works that explained his belief that alcohol expanded more regularly than mercury, and his experiments matched his scale more accurately than mercury did.Mapping the Alps
During his time at Aarburg CastleAarburg Castle
Aarburg Castle is a castle in the municipality of Aarburg in the canton of Aargau in Switzerland. It is located high above the Aarburg on a steep, rocky hillside. The castle was built around a medieval castle, which controlled the narrow point on the Aare river and served as the seat of Aarburg...
he published many meteorological papers and created a cartographical drawing of the Alps as viewed from the castle. Without any modern equipment, such as a theodolite
Theodolite
A theodolite is a precision instrument for measuring angles in the horizontal and vertical planes. Theodolites are mainly used for surveying applications, and have been adapted for specialized purposes in fields like metrology and rocket launch technology...
or telescope
Telescope
A telescope is an instrument that aids in the observation of remote objects by collecting electromagnetic radiation . The first known practical telescopes were invented in the Netherlands at the beginning of the 1600s , using glass lenses...
he instead used an eight-meter long gutter pipe, filled with water to measure levels and a small rod held in front of it, he could measure the heights of the peaks. He then used the Scheuchzer map of 1712 to calculate the distances away, and drew the first scientific panorama of the Alps.