Mr Smellie--who was at all times an abstemious man--contented himself with a couple of gla.s.ses of wine after dinner, and, the moment that the conversation took a general turn, rose from the table, excusing himself upon the plea that he had several matters to attend to in connection with the expedition. As he rose he caught my eye and beckoned me to follow him, which I did after duly making my bow to the company.

When we reached the deck the fog was so thick that it was as much as we could do to see the length of the ship.

"Just as I expected," remarked my companion. "How are we to find the creek in such weather as this, Mr Hawkesley?"

"I am sure I don't know, sir," I replied, looking round me in bewilderment. "I suppose the expedition will have to be postponed until it clears a bit."

"Not if I can prevent it," said he with energy. "Although," he added, a little doubtfully, "it certainly _is very_ thick, and with the slightest deviation from our course we should be irretrievably lost. Whereaway do you suppose the creek to be?"

"Oh, somewhere in that direction!" said I, pointing over the starboard quarter.

"You are wrong," remarked my companion, looking into the binnacle. "The tide is slackening, whilst the land-breeze is freshening; so that the ship has swung with her head to the eastward, and the direction in which you pointed leads straight out to sea. Now, if you want to learn a good useful lesson--one which may prove of the utmost value to you in after- life--come below with me to the master, and between us we will show you how to find that creek in the fog."

"Thank you," said I, "I shall be very glad to learn. Why, you do not even know its compa.s.s-bearing."

"No," said Smellie, "but we will soon find it out." With that we descended to the master's cabin, where we found the owner in his shirt- sleeves and with a pipe in his mouth, poring over a chart of the coast on which was shown the mouth of the river only, its inland course being shown by two dotted lines, indicating that the portion thus marked had never been properly surveyed. He was busily engaged as we entered laying down in pencil upon this chart certain corrections and remarks with reference to the ebb and flow of the tidal current.

"Good evening, gentlemen!" said he as we entered. "Well, Mr Smellie, so you are going to lead the attack upon the slavers to-night, I hear."

"Yes," said Smellie, unconsciously straightening himself up, "yes, if this fog does not baffle us. And in order that it may not, I have come to invoke your a.s.sistance, Mr Mildmay."

"All right, sir!" said old Mildmay. "I expected you; I was waiting for you, sir."

"That's all right," said the second lieutenant. "Now, Mildmay," bending over the chart, "whereabouts is the _Daphne_?"

"_There_ she is," replied the master, placing the point of his pencil carefully down on the chart and twisting it round so as to produce a black mark.

"Very good," a.s.sented Smellie. "Now, look here, Mr Hawkesley, this is where your lesson begins." And he produced the sketch-chart he had made that afternoon and spread it out on the table.

"You will see from this sketch," he proceeded, "that the _Daphne_ bore exactly north-north-west from the tree in which we were perched when I made it. Which is equivalent to saying that the tree bears south-south- east from the _Daphne_; is it not?"

I a.s.sented.

"Very well, then," continued Smellie. "Be so good, Mr Mildmay, as to draw a line south-south-east from that pencil-mark which represents the _Daphne_ on your chart."

The master took his parallel ruler and did so.

"So far, so good," resumed the second lieutenant. "Now my sketch shows that the outer extremity of Shark Point bore from the tree north-west west. In other words, the tree bears from Shark Point south-east east. Lay off that bearing, Mildmay, if you please."

"Very good," he continued, when this second line had been drawn. "Now it is evident that the point where these two lines intersect must be the position of the tree. But, as a check upon these two bearings I took a third to that sharp projecting point at the mouth of Banana Creek,"

indicating with the pencil on the chart the point in question. "That point bears north-west by north; consequently the tree bears from it south-east by south. Mark that off also, Mildmay, if you please."

The master did so, and the three lines were found to intersect each other at exactly the same point. "Capital!" exclaimed Smellie, in high good-humour. "That satisfactorily establishes the exact position of the tree. Now for the next step. The slave fleet bears north-west west from the tree; and the western entrance to the creek (that by which we shall advance to the attack to-night) bears exactly north-west from the same point. Let us lay down these two bearings on the chart--thus. Now it is evident that the slave fleet and the entrance to the creek are situate _somewhere or other_ on these two lines; the question is--_where_? I will show you how I ascertained those two very important bits of information if you will step to my cabin and bring me the telescope which you will find hanging against the bulkhead."

Intensely interested in this valuable practical lesson in surveying I hurried away to do his bidding, and speedily returned with the gla.s.s, a small but very powerful instrument, which I had often greatly admired.

Taking the telescope from my hand he drew it open and directed my attention to a long series of neat little numbered lines scratched on the polished bra.s.s tube.

"You see these scratches?" he said. "Very well; now I will explain to you what they are. When I was a midshipman it was my good fortune to be engaged for a time on certain surveying work, during which I acquired a tolerably clear insight of the science. And after the work was over and done with, it occurred to me that my knowledge might be of the greatest use in cases similar to the present. Now I may tell you, by way of explanation, that surveying consists, broadly, in the measurement of angles and lines. The angles are, as you have already seen, very easily taken by means of a pocket-compa.s.s; but the measurement of the lines bothered me very considerably for a long time. Of course you can measure a line with perfect accuracy by means of a surveyor's chain, but I wanted something which, if not quite so accurate as that, would be sufficiently correct, while not occupying more than a few seconds in the operation of measurement. So I set to work and trained myself to judge distances by the eye alone; and by constant diligent practice I acquired quite a surprising amount of proficiency. And let me say here, I would very strongly recommend you and every young officer to practise the same thing; you will be surprised when you discover in how many unexpected ways it will be found useful. Well, I managed to do a great deal of serviceable work even in this rough-and-ready way; but after a time I grew dissatisfied with it--I wanted some means of measuring which should be just as rapid but a great deal more accurate. I thought the matter over for a long time, and at last hit upon the idea of turning the telescope to account. The way I did it was this. You have, of course, found that if you look through your telescope at an object, say, half a mile away, and then direct the instrument to another object, say, four miles off, you have to alter the focus of the gla.s.s before you can see the second object distinctly. It was this peculiarity which I pressed into my service as a means of measuring distances. My first step was to secure a small, handy, but first-rate telescope--the best I could procure for money; and, provided with this, I commenced operations by looking through it at objects, the exact distances of which from me I knew. I focused the gla.s.s upon them carefully, and then made a little scratch on the tube showing how far it had been necessary to draw it out in order to see the object distinctly; and then I marked the scratch with the distance of the object. You see," pointing to the tube, "I have a regular scale of distances here, from one hundred yards up to ten miles; and these scratches, let me tell you, represent the expenditure of a vast amount of time and labour. But they are worth it all. For instance, I want to ascertain the distance of an object. I direct the telescope toward it, focus the instrument carefully, and find that I can see it most clearly when the tube is drawn out to, say, this distance,"

suiting the action to the word. "I then look at the scale scratched on the tube, and find that it reads six thousand one hundred feet--which is a few feet over one nautical mile. And thus I measure all my distances, and am so enabled to make a really satisfactory little survey in a few minutes as in the case of this afternoon. You must not suppose, however, that I am able to measure in this way with absolute accuracy; I am not; but I manage to get a very near approximation to it, near enough for such purposes as the present. Thus, within the distance of a quarter of a mile I have found that I can always measure within two feet of the actual distance; beyond that and up to half a mile I can measure within four feet of the actual distance; and so on up to ten miles, which distance I can measure to within four hundred feet.

"And now to return to the business in hand. My telescope informed me that the slave fleet was anch.o.r.ed at a distance of eighteen thousand three hundred feet (or a shade over three nautical miles) from the tree, and that the western entrance to the creek is twenty-eight thousand nine hundred feet (or about four and three-quarter nautical miles) from the same spot. We have now only to mark off these two distances on the two compa.s.s-bearings which we last laid down on the chart: thus,"--measuring and marking off the distances as he spoke--"and here we have the position of the slavers and of the entrance to the creek; and by a moment's use of Mildmay's parallel ruler--thus--we get the compa.s.s- bearing of the entrance from the _Daphne_. There it is--south-east by east; and now we measure the distance from one to the other, and find it to be--eight miles, as nearly as it is possible to measure it. Thus, you see, my rough-and ready survey of this afternoon affords us the means of ascertaining our course and distance from the _Daphne_ to a point for which we should otherwise have been obliged to search, and which we could not possibly have hoped to find in the impenetrable fog which now overspreads the river."

"Thank you, Mr Smellie," said I, highly delighted with the lesson I had received; "if it will not be troubling you too much I think I must ask you to give me a lesson or two in surveying when you can spare the time."

"I shall be very pleased," was the reply. "Never hesitate to come to me for any information or instruction which you think I may be able to afford you. I shall always be happy to help you on in your studies to the utmost extent of my ability. But we have not quite finished yet, and it is now, Mildmay, that I think _you_ may perhaps be able to help us. You see we shall have to pull--or sail, as the case may be--_across_ the current, and it will therefore be necessary to make some allowance for its set. Now do you happen to know anything about the speed of the current in the river?"

"Not half so much as I should like," replied the master; "but a hint which the skipper dropped this morning caused me to take the dinghy and go away out in mid-stream _to spend the day in fishing_--ha--ha--ha!

The Yankee had his gla.s.s turned full upon me, off and on, the whole morning--so I'm told--and if so I daresay he saw that I had some fairly good sport. But I wasn't so busy with my hooks and lines but that I found time to ascertain that the ebb-stream runs at a rate of about four knots at half-tide; and just abreast of us it flows to seaward at the rate of about one knot at half-flood; the salt water flowing _into_ the river along the bottom, and the fresh water continuing to flow _outwards_ on the surface. Now, at what time do you propose to start?"

"About half-past nine to-night," answered Smellie.

Old Mildmay referred to a book by his side, and then said:

"Ah, then you will have about two hours' ebb to contend with--the last two hours of the ebb-tide. Now let me see,"--and he produced a sheet of paper on which were some calculations, evidently the result of his observations whilst "Sshing." He ran over these carefully, and then said:

"How long do you expect it will take you to cross?"

"Two hours, if we have to pull across--as I expect we shall," answered the second lieutenant.

"Two hours!" mused the master. "Two hours! Then you'll have to make allowance, sir, for an average set to seaward of two miles an hour all the way across, or four miles in all."

"Very well," said Smellie. "Then to counteract that we must shape our course for a point four miles _above_ that which marks the entrance to the creek--must we not, Mr Hawkesley?"

"Certainly," I said; "that is quite clear."

"Then be so good as to lay that course down on the chart."

I measured off a distance of four miles with the dividers, and marked it off _above_ the mouth of the creek; then applied the parallel ruler and found the course.

"It is exactly south-east," said I; "and it will take us close past the southern extremity of this small island."

"That is quite right," remarked Smellie, who had been watching me; "and if we happen to sight the land in pa.s.sing that point it will be an a.s.surance that, so far, we have been steering our proper course. But-- bless me,"--looking at his watch--"it is a quarter after nine. I had no idea it was so late. Run away, Mr Hawkesley, and make your preparations. Put on your worst suit of clothes, and throw your pea- jacket into the boat. You may be glad to have it when we get into the thick of that damp fog. Bring your pistols, but not your dirk; a ship's cutla.s.s, with which the armourer will supply you, will be much more serviceable for the work we have in hand to-night."

I hastened away, and reached the deck again just in time to see the men going down the side into the boats after undergoing inspection.

CHAPTER EIGHT.

WE ATTACK THE SLAVERS.

The attacking flotilla was composed of the launch, under Mr Smellie, with me for an _aide_; the first cutter, in charge of Mr Armitage, the third lieutenant; and the second cutter, in charge of Mr Williams, the master's mate; the force consisting of forty seamen and four officers-- quite strong enough, in Captain Vernon's opinion, to give a satisfactory account of the three slavers, which, it was arranged, we were to attack simultaneously, one boat to each vessel.

The last parting instructions having been given to Smellie by the skipper, and rounded off with a hearty hand-shake and an earnest exclamation of "I wish you success;" with a still more hearty hand-shake and a "Good-bye, Harold, old boy; good luck attend you!" from Mr Austin, the second lieutenant motioned me into the launch; followed me closely down; the word to shove off was given, and away we went punctually at half-past nine to the minute.

The fog was still as thick as ever; so thick, indeed, that it was as much as we could do to see one end of the boat from the other; and, notwithstanding the care with which, as I had had an opportunity of seeing, the second lieutenant had worked out all his calculations, I own that it seemed to me quite hopeless to expect that we should find the place of which we were in search. Nevertheless, we pushed out boldly into the opaque darkness, and the boats' heads were at once laid in the required direction, each c.o.xswain steering by compa.s.s, the lighted binnacle containing which had been previously masked with the utmost care. Our object being to take the slavers by surprise the oars were of course m.u.f.fled, and the strictest silence enjoined. Thus there was neither light nor sound to betray our whereabouts, and we slid over the placid surface of the river almost as noiselessly as so many mist- wreaths.

In so dense a fog it was necessary to adopt unusual precautions in order to prevent the boats from parting company. We therefore proceeded in single file, the launch leading, with the first cutter attached by her painter, the second cutter, in her turn, attached by her painter to the first cutter, bringing up the rear. The cutters were ordered to regulate their speed so that the connecting rope between each and the boat ahead should be just slack enough to dip into the water and no more, thus insuring that each boat's crew should do its own fair share of work at the oars.