Cassini (1768)

Cassini, Jean-Dominique (1748-1845). Voyage fait par ordre du roi en 1768, pour éprouver les montres marines inventées par M. Le Roy [...]. Paris: Charles-Antoine Jombert, 1770.

If there ever was a person predestined for a career, it was unquestionably Jean-Dominique Cassini, because he was born, as it were, right in the midst of the stars. In fact, he came into this world in June of 1748 in France's Royal Observatory, which was under his father's direction.

As the son, grandson and great-grandson of astronomers, Cassini followed the same course. In 1768, when he was only 20, he was appointed "commissioner for testing marine watches" invented by a man named Le Roy. For a long time sailors had managed to determine their position north or south (latitude) with relative accuracy by using the square, quadrant and sextant; on the other hand, to determine their position east or west (longitude) they still used the log line, a very primitive method that led them to make considerable errors. The chronometer perfected by Le Roy was supposed to surpass the log line in accuracy.

Back from his expedition, which had taken him to North America and then along the coasts of Africa, Cassini published his first scientific work, which concluded cautiously as follows: " ... I have some hope of having ... determined the best way to measure time at sea."

In 1770 Cassini was admitted to the Academy of Sciences as an associate astronomer, and in 1784 he succeeded his father as director of the Royal Observatory. But in the early 1790s, during the French Revolution, the Academy of Sciences was suppressed and Cassini was fired from the Observatory. These events put a premature end to his career as an astronomer, even though he joined the new Academy of Sciences in 1799. Later, after becoming mayor of Thury, Cassini busied himself mainly with farming and forestry. He died in 1845, almost a centenarian.

Homepage

Previous      Next

Previous      Next