Gilling's cheerful optimism was the sort of desirable quality that is a good thing to have, but all the optimism in the world is valueless in face of impregnable difficulty. And the difficulty of tracing Chatfield and his sick companion in a city the size of Bristol did indeed seem impregnable when Gilling and Copplestone had been attacking it for twenty-four hours. They had spent a whole day in endeavouring to get news; they had gone in and out of hotels until they were sick of the sight of one; they had made exhaustive inquiries at the railway station and of the cabmen who congregated there; nobody remembered anything at all about a big, heavy-faced man and a man in his company who seemed to be very ill. And on the second night Copplestone intimated plainly that in his opinion they were wasting their time. "How do we even know that they ever came to Bristol?" he asked, as he and Gilling refreshed themselves with a much needed dinner. "The Falmouth landlord saw Chatfield take tickets for Bristol! That's nothing to go on! Put it to yourself in this way. Greyle may have found even that journey too much for him. They may, in that case, have left the train at Plymouth--or at Exeter--or at Taunton: it would stop at each place. Seems to me we're wasting time here--far better get nearer more tangible things. Chatfield, for instance. Or, go back to town and find out what your friend Swallow has done." "Swallow," replied Gilling, "has done nothing so far, or I should have heard. Swallow knows exactly where I am, and where I shall be until I give him further notice. Don't be discouraged, my friend--one is often on the very edge of a discovery when one seems to be miles away from it. Give me another day--and if we haven't found out something by tomorrow evening I'll consult with you as to our next step. But I've a plan for tomorrow morning which ought to yield some result." "What?" demanded Copplestone, doubtfully.