On the Kantineplein in Heverlee stands a statue of Duke Louis Engelbert of Arenberg and Jan Pieter Minckelers. They look out over the lawn of Arenberg Castle, where, one autumn day in 1783, the first unmanned balloon in the Low Countries was released.
Minckelers, the son of a pharmacist in Maastricht, was only sixteen when he arrived in Leuven to study theology in January 1765. Like all students, he first had to take two years of general courses at the Artes Faculty. Minckelers became so fascinated with physics, and turned out to have such an aptitude for the subject, that after his theology studies he was appointed professor of physics and started working as an assistant to Professor Jan Frans Thysbaert, manager of the laboratory for experimental physics. This lab was located in what is now Vanderkelenstraat; its portico still exists today, forming the entrance to Museum M.
Louis Engelbert, also known as the blind Duke after he lost his eyesight in a hunting accident, was a great science enthusiast and one of the first patrons of the University of Leuven to finance empirical research. He would take his guests to Thysbaert and Minckelers' laboratory whenever he stayed at his castle in Heverlee during the summer. The Duke had contacts with famous instrument makers in various foreign countries and provided the professors with both the materials and means for their research.
And then there was light
Even in 1778, the desire for knowledge led to scientific progress. Minckelers and Thysbaert, for example, wanted to find an inflammable gas that could be used as a safe and cheap alternative to candles and oil lamps. In 1783, Minckelers wrote in his notebook how he had succeeded in producing such a lighting gas by filling the barrel of a gun with coal, cutting off the oxygen supply, and heating the barrel.
Coal gas became widely used in public street lighting in the following decades. In 1817, Brussels became the first city in continental Europe to have gas lanterns; Leuven would have to wait until 1835. A gas plant was built along the Vaart, the Louvain canal. Cast-iron pipes transported the gas throughout the city, where lantern lighters made their rounds every evening and morning. Gradually, public buildings, monasteries, castles and private homes were also equipped with gas chandeliers. Minckelers ensured that his own auditorium would be lit with the new technique as early as 1784. However, the system turned out to have a number of downsides as well, from blackened ceilings to carbon monoxide poisoning.
However, the system turned out to have a number of downsides as well, from blackened ceilings to carbon monoxide poisoning.
To the sky
The research into coal gas had been boosted by the blind Duke's fascination with the balloon experiments of the Montgolfier brothers and physicist Jacques Charles in Paris in August 1783. Those experiments respectively used burning wool and straw, and hydrogen. However, the former was prone to accidents, while the latter was expensive and difficult to manufacture. The Duke had balloons made in Brussels from goldbeater’s skin – processed cow intestines – and wanted to find a gas that was lighter than air. He found his solution in the coal gas that was the subject of Minckelers’ and Thysbaert’s experimentation.
That's why, on 20 November 1783, the very first gas balloon in the Low Countries could be released on the lawn in front of Arenberg Castle. According to Minckelers' notes, the balloon, which was almost two feet (56 centimetres) in diameter, flew in the direction of Maastricht.
Political unrest during the Brabant Revolution led Minckelers to return to his home town in 1790, where he died in 1824. Eighty years later, a statue of him was unveiled there on the Markt. In his left hand, Minckelers holds a gas pipe that, to this day, produces a powerful flame in exchange for a coin.