| Birth Date: | 10 November 1833 |
| Birth Place: | Pignet, Gard, France |
| Death Date: | 15 April 1875 (aged 41) |
| Branch: | French Navy |
| Battles: | Franco-Prussian War |
| Later Work: | balloon ascents |
Théodore Sivel (10 November 1833 – 15 April 1875) was a French navy officer and aeronaut. He designed and died on the gas balloon Zénith.
Théodore Henri Sivel was the son of Alexandre Sivel and Caroline Brès, a Protestant family. He was born in Pignet, a kilometer southeast of Sauve, in the family home.[1]
At the age of 14years, he embarked on distant seas and sailed for nearly twenty years, circumnavigating the globe multiple times. He became a long-distance captain. He was part of the French delegation that attended the coronation of Radama, King of Madagascar.
Around 1866, the naval officer, attracted by air navigation, abandoned the seas for the skies.
In 1867, he married Marie Poitevin in Bern, who passed away the following year in Naples.
He served France during the Franco-Prussian War of 1870.
In 1872, he joined the Paris Aeronautical Navigation Society and caught the attention of the scientific world by presenting his project of "exploring the North Pole by balloon". He invented several improvement accessories such as the 'guide-rope with floats' or the 'cone-anchor'.[2] He completed nearly 200 ascents, the first on 26 April 1872.
On 22 March 1874, with engineer, he ascended in a balloon (the Étoile polaire) to an altitude of 7400m (24,300feet), from the gasworks of La Villette to Bar-sur-Seine. This ascent allowed for testing the use of oxygen (equipment developed by Paul Bert) and making astronomical observations (to determine whether the atmosphere alters observations of the sun and stars made from the ground) using an apparatus constructed by Jules Janssen.[3] [4]
On March 23 and, under the guidance of Paul Bert,[5] he participated as captain in the record flight duration of the Zénith from Paris to Arcachon. This achievement elevated the three aeronauts to hero status.On 15 April 1875, he departed aboard the same balloon with Joseph Crocé-Spinelli and Gaston Tissandier near the gasworks in the La Villette district, in the 19th arrondissement of Paris, and died of asphyxiation (hypoxia) at Ciron with Crocé-Spinelli during this new ascent aimed at breaking the flight altitude record aboard the Zénith, from which only Gaston Tissandier survived. The disaster was attributed to a lack of precaution,[6] ignorance of the issues related to an altitude above 8000m (26,000feet)[7] and the too rapid ascent of the Zénith.[8] Tissandier himself described his adventure and that of his friends in La Nature[9] and in L'Aéronaute.[10] “During the Great War,, who had been the editor of Gaston Tissandier, wrote in a memoir that this great aeronaut had revealed certain details about the Zénith disaster which he had deliberately kept from the public. It was learned that it was Sivel, and not Crocé-Spinelli, who was responsible for the sudden and fatal ascent of the balloon. Sivel, who was in charge of monitoring the balloon's altitude with a barometer, may have been misled by his myopia and mistakenly thought the aerostat was about to touch the ground. It was he who then threw overboard everything within reach.”
"In all the drawings of the disaster..., the real shape of the Zénith basket was replaced by a square basket of less crude and more advantageous construction".[11]
At the time of his death at age 40, Sivel left behind Marie, a six-year-old orphaned daughter. A national subscription raised nearly 10,000 French franc for the two grieving families.
Regarded as heroes of Science, Sivel and Crocé-Spinelli were given a funeral in Paris attended by more than twenty thousand people, with the procession starting from the Gare d'Orléans and proceeding to the cimetière du Père-Lachaise, passing through the Oratoire du Louvre where the ceremony was presided over by Pastor Dide. Sivel was buried in section 71, under a gisant sculpted in 1878 by Alphonse Dumilatre, depicting him lying on his back holding the hand of his unfortunate flight comrade.[12]