By kind permission of Baron de Bradsky's widow, I am enabled to give an authentic account of his ideas concerning the “ de Bradsky ” balloon, of its construction, and of the causes that produced the lamentable accident on October 13lh, 1902, in which Baron de Bradsky (Fig. 1) [to the left] and his engineer, Morin [to the right], lost their lives. Baroness de Bradsky thought it due to her husband's memory to have this account published, particularly as the details in the papers at the time of the accident were more or less incorrect, and none of their authors had grasped the fundamental idea which actuated Baron de Bradsky in the construction of his airship ; Baroness de Bradsky was also of the opinion that a reliable account would be of interest to aëronauts in general, and might be of use in solving the numerous and difficult problems which assail them.