In July 1849, in the first aerial bombardment in history, the Austrians launched an aerial attack on the beseiged Venice, in the Republic of San Marco. They released balloons carrying, it was claimed, 30lb bombs. According to a report in the Scientific American of the previous March from Vienna, the intention of the Austrians had been to launch five balloons 23 feet in diameter each carrying 5 bombs which were to be ignited by means of electromagnetism, using a long copper wire connected to a large galvanic battery on the shore. Though reports of the actual raid conflict in that it is not clear whether 2 or 20 balloons took part in the raid, none suggest that this system was employed, but they do not dispute that the attack was largely unsuccessful, and Venice did not surrender to the Austrian Empire until August 27 1849.