“Who was Delambre?” I wonder. Here at Square Delambre, we honor Jean-Baptiste-Joseph Delambre. This square is named after him because of its proximity to Rue Delambre.
Square Delambre is located in the 14th arrondissement of Paris. Specifically, it sits in the Montparnasse neighborhood. The Square Delambre begins at 19, Rue Delambre. It ends at 26, Boulevard Edgar-Quinet. The area is accessible via the Edgar Quinet station on line 6. Also, you can use the Vavin station on line 4.
Delambre was quite the figure. He excelled as an astronomer, mathematician, and geodesist. Born in Amiens, France, his father was a draper. “Delambre” likely came from “de Lambre,” meaning “rag.”
Jean-Baptiste-Joseph Delambre was the eldest child. As a baby, smallpox almost took his life. His eyelashes never grew back. This gave him a unique look in portraits. Remarkably, he pursued astronomy despite his early vision problems.
At the Jesuit College in Amiens, he studied under Abbé Jacques Delille. Delambre studied English and German. After the Jesuits were banned in 1764, he continued his education in Amiens. One of his new teachers encouraged him to study in Paris.
Delambre obtained a scholarship to the Collège du Plessis in Paris. However, he failed his university entrance exams due to his eyesight. Unable to afford university, he remained in Paris to educate himself. He became a tutor to a nobleman’s son in Compiègne. Delambre had to teach himself mathematics to tutor his pupil.
In 1771, Delambre tutored Jean-Claude Geoffroy d’Assy’s son. This position allowed him to live cheaply. Also, it allowed him to learn all he could. At this time, he called himself Abbé de Lambre. Later, during the Revolution, he changed it to Delambre. This was to avoid any aristocratic associations.
Delambre’s interests shifted to Greek science and astronomy. Around 1780, he began attending Lalande’s astronomy lectures. He impressed Lalande with his knowledge. In 1783, Lalande hired Delambre as an assistant.
In 1786, Delambre recorded a transit of Mercury across the Sun. He realized existing tables were inaccurate. So he devoted himself to creating new ones.
In 1788, Lalande wrote a letter praising Delambre. He called him the most able astronomer. The Academy announced a Grand Prix for calculating Uranus’s orbit in 1789. Delambre had already completed much of the work. The committee awarded him the prize.
By 1789, Delambre had his own observatory. Geoffroy d’Assy built it for him. It was above his bedroom on the top floor.
In 1792, Delambre published Tables du Soleil, de Jupiter, de Saturne, d’Uranus et des satellites de Jupiter. That same year, he received the Grand Prix of the Académie des Sciences. He was elected an associate member.
The Académie des Sciences tasked him with calculating the length of the meridian. It was to help define the metric system. Delambre was in charge of the Dunkerque to Rodez sector. Méchain handled the Rodez to Barcelona sector.
In 1795, he was admitted to the Bureau des Longitudes. He became its President in 1800. In 1801, he became secretary to the Académie des Sciences.
In 1807, Delambre was appointed to the chair of astronomy at the Collège de France. He also became treasurer to the Imperial University in 1808.
Napoleon requested the Académie des Sciences award a prize for the best scientific publication. Delambre won for his work on the meridian.
In his final years, Delambre studied the history of mathematics and astronomy. He wrote extensively on these subjects. Delambre is honored by a large lunar crater named after him.
Today, Square Delambre is a peaceful spot. Beautiful brick and stone residences surround it. These buildings belong to the AP-HP. In 2024, the city of Paris expanded and improved Square Delambre. This was part of the “Embellir notre quartier” program.