Before they arrived off Ferrol they heard from a frigate that Villeneuve had left the port. He had put to sea as though intending to cross the Bay of Biscay direct to Brest, but when two days out, had suddenly, for some unfathomable reason of his own, gone about and stood southward. Whither he was bound could only be guessed, but Calder's orders were to follow the French wherever they might go, and he made for the Straits of Gibraltar under all sail. Did he pass over a certain spot, some ninety miles north-west of Cape Finisterre, where a mass of frigate wreckage and splinters and jagged chips was floating about--like the ring of fluttered feathers that one sometimes sees at the corner of a wood on an autumn afternoon telling how a sparrow-hawk has passed that way? That flotsam off Finisterre, could it have spoken, would have told a tale; the story of the incident on which the campaign of Trafalgar hinged:--_why_ Admiral Villeneuve had gone south instead of north.[89] Off Cadiz Calder found Collingwood with half a dozen ships, and learned that the French were refitting in that port. Collingwood had had the narrowest of narrow escapes of being cut off and overpowered by the enemy's sudden appearance off Cadiz,[90] but he had cleverly got out of their way in the nick of time, and was now 'observing' them, making believe by sham signals every day that he was in touch with a large British fleet in the offing. Collingwood as the senior officer took Calder under his orders, and the united forces continued to watch Cadiz until at the end of September Lord Nelson himself arrived from England to take the supreme command. For three weeks, as we all know, Nelson kept watch and ward over the enemy in Cadiz, until on the morning of Saturday the 19th of October his look-out frigates off the mouth of Cadiz harbour at last made the longed-for signal that the combined fleet was coming out of port.