Marshall took the sketch and considered it attentively. “Yes,” he said at length, “that ought to be near enough for our purpose. But how are you going to measure your line?”
“Quite easily,” answered Dick. “When I learned that I was to accompany you, the idea of drawing a chart of the harbour at once occurred to me, and I thought out the plan that I have just explained to you. I also borrowed from the carpenter a ball of fine cord, which I then proceeded to knot very carefully at every foot, measured with the carpenter’s rule. Here it is, just one hundred feet long; and with the help of it we ought to have no difficulty in measuring our line.”
Nor had they: for the hilltop was quite level enough for their purpose. They measured it twice, going and returning, in order to ensure the greater accuracy, and, laying down their work on paper to scale as they proceeded, managed before dark to secure an exceedingly useful and tolerably complete chart of the upper bay and inner harbour, with the help of which they felt that they ought to be able to find their way to the town, even on the darkest night. Of course they were not able to ascertain the depth of water by this means; but the even colour of it seemed to indicate that there were no hidden dangers to guard against anywhere except just inside the entrance of the inner harbour, where the presence of a shoal obstructing the fairway was clearly indicated by a certain glassiness of surface, which was duly recorded upon the chart.
The preparation of this chart served to familiarise them with the principal features of the harbour in a really wonderful manner, and to fix in their memories the relative positions of them one with another. But that was not all; for while they were at work their eyes were busy noting various details, one of which was that a small fishing village existed at the base of the hill upon which they were at work, and not more than half a mile from the spot where the longboat lay concealed. This was a discovery of some importance to them, for it at once suggested the possibility of “borrowing” a canoe from the village, after dark, and proceeding in her to the city; by which plan they would run much less risk of detection than if they attempted to reach the city with the longboat.
They completed their labours and set out to walk down the hill on their way to the boat while the sun was still nearly an hour above the horizon, and were safely aboard her again ere darkness fell. Then, having partaken of a meal, Marshall and Dick stretched themselves along in the stern-sheets of the boat, in order to snatch an hour or two of sleep before embarking upon by far the most hazardous part of their enterprise, namely, their excursion to the city of Cartagena.
Marshall had given instructions that he and Dick were to be called punctually at eight o’clock; but when that hour arrived and the man who had the watch proceeded to arouse them, it appeared that the Captain was already awake, not having been to sleep at all, in fact; and as Dick seemed to be fast locked in the arms of slumber, Marshall softly whispered to the man who was about to arouse him, that he was to be permitted to sleep on, at the same time composing himself to rest and giving fresh instructions that both were to be called at midnight. From which it was evident that in the interim he had modified his original plan.
When at length midnight arrived and the pair were duly awakened Marshall remarked with a grin which the darkness effectually concealed:
“Well, lad, hast had a good sleep?”
“Excellent,” answered Dick. “I feel as fresh as a lark, and can scarcely realise that I have only been asleep two hours.”
“Two hours!” retorted Marshall, with a laugh. “Thou hast had six hours of good, honest sleep; and ’tis midnight instead of eight o’clock. The fact is,” he continued in more serious tones, “I could not sleep when I first attempted to do so. My thoughts were busy with the task that lay before me; and I could not see how it was to be done in the time that I had allowed myself. The way that I looked at the matter was this: I had arranged that we were to start from here at eight o’clock. By the time that we had found our way round to the village where we hoped to get a canoe, it would be nearly or quite nine; and by the time that we reached Cartagena it would be ten o’clock, or after; there would be no work doing, and most of the good folk would be abed; thus I should stand a very poor chance of gaining any information worth having. The proper time for me to be ashore, there, is during the day, when everybody is astir, when there are plenty of people about to talk to and ask questions of, and when they will be too busy to take particular note of me, and wonder who I am and where I came from. So I altered my plan, deferring our departure until now, which will afford me plenty of time to get into the city before daylight. Then I shall have the whole day before me, if I find that I require it, in which to look about me and make a few discreet enquiries; and as soon after dark as it is safe to return I will come back; reaching the boat, if all be well, in time to go out and rejoin the Adventure to-morrow night about this time. Now, I shall want you to go with me as far as the village, to help me, if need be, to secure a canoe; and when I have done that, and am fairly under way, you can come back here to the boat, and wait for me; for the work that I have to do can best be done single-handed. Now, if you have any questions to ask, ask them; but if not, we may as well be off, for I want to allow myself plenty of time to make my way into the town.”