“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 glass 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?”