SOME important experiments with captive balloons have lately been made in the Mediterranean squadron of the French navy. By the courtesy of the editor of La Nature, we are enabled to give, on the next page, a representation of the most interesting of these experiments, which was made on board the ironclad Le Formidable. All the officers who mounted in the car declare that it afforded an excellent point of observation. In clear weather they could distinguish, from Lagoubran, all the details of the coast from the entrance to Mar-seilles to the eastern extremity of the Islands of Hyé res. No ship within a radius of from 30 to 40 kilometres could have escaped observation. With a cable of silk, the balloon could rise in calm weather to a height of 400 metres.