Starting on 3 November 1859, the first phase of the Commission's work was a series of interviews with technical experts and senior military and naval officers. One specialist was Captain Cowper Phipps Coles, the hero of the Siege of Taganrog and an expert in the bombardment of fortifications from the sea. He was so enraged by the numerous questions posed by the Commissioners that he was twice asked to leave the room so that he could recover his composure. Perhaps because of this, the Commission failed to enquire about Coles's pioneering design for a revolving gun turret, which he had patented in that year. Another interviewee was General John Fox Burgoyne, who had conducted the Siege of Sevastopol and was the current Inspector-General of Fortifications. Burgoyne's opinion was that the defence of the dockyard at Portsmouth was of primary importance and it could be protected from bombardment by the fortification and garrisoning of the Isle of Wight and also Portsdown Hill, the ridge which overlooks Portsmouth from the north. Burgoyne also believed that the coast between Portsmouth and the Thames was vulnerable to invasion and that every small harbour there needed to be fortified. Sir William Armstrong, the artillery designer and manufacturer, was questioned at length about the current capabilities of modern rifled artillery and likely future developments. Armstrong's opinion was that his latest guns would be able to defeat some features of current fortification, such as the Carnot wall, but that the maximum range of artillery would be unlikely to exceed 5 miles (8 kilometres) in the future.