BALLON MONTÉ 1870 - entire letter dated inside ”Sept 30” with red cachet of the AEROSTIER NADAR-D´ARTOIS-DURUOF on reverse. The franking had been lost in transit and the receiver wrote ”timbre decollée”. The letter was first entrusted (pli confíe) to the Aerostier company but as for a 7 day period from the afternoon of September 30 to October 7 no Ballon Monté departures were planned (the ”Non Dénommé Nr 1” only carried post cards), the aérostiers company finally preferred to mail it directly through the Paris post office instead of keeping it for further 7 days. At the post office it received the departure cds ” PARIS ST NAZARE 30 SEPT 70 ”. The letter arrived in Angers on October 15th (Maine et Loire) and was re-directed to St Malo (Ille et Vilaine) on the 17 th of October and finally found its addressee in Angers October 18th. It was probably flown by the Ballon ”le Washington” as noted in manuscript by the receiver. THIS IS THE ONLY RECORDED BALLON MONTÉ COVER SHOWING THE CACHET OF THE AEROSTIER COMPANY NADAR-D´ARTOIS-DURUOF THAT WAS SENT THROUGH THE NORMAL PARIS POST. A MAJOR 1870 WAR RARITY ! For comparison the Maury catalogue prices covers with the Nadar cachet d´aéronaute flown during the first two weeks of October 1870 at a minimum of 9500€, our unique retracted pli confié should at least have an estimated catalogue value of + 100% = 19000€. CERTIFICATE PASCAL SCHELLER.