This envelope originated from the Paris office at Rue d’Antin on November 29, 1870, (third collection) and was prepaid 30 centimes for the ordinary letter rate to England, “Par Ballon Monté.” Based on the date of collection plus the London arrival datestamp of December 5, 1870, it is likely that this letter was carried out of Paris by the balloon Jules Favre No. 2.
The Jules Favre No. 2 carried 110 kilograms of mail, and the flight was conducted in heavy winds that carried the balloon out to sea. Luckily, it was able to descend onto the island of Belle-Ile-en-Mer. However, the landing was rough, and both aeronauts were injured.