I wonder whether the Ebba will render her the customary salute as she passes.

No; for the schooner suddenly changes her course with the evident intention of avoiding her.

This proceeding on the part of such a suspicious yacht does not astonish me greatly.  But what does cause me extreme surprise is Captain Spade’s way of manoeuvring.

He runs forward to a signalling apparatus in the bows, similar to that by which orders are transmitted to the engine room of a steamer.  As soon as he presses one of the buttons of this apparatus the Ebba veers off a point to the south-west.

Evidently an order of “some kind” has been transmitted to the driver of the machine of “some kind” which causes this inexplicable movement of the schooner by the action of a motor of “some kind” the principle of which I cannot guess at.

The result of this manoeuvre is that the Ebba slants away from the cruiser, whose course does not vary.  Why should this warship cause a pleasure-yacht to turn out of its way?  I have no idea.

But the Ebba behaves in a very different manner when about six o’clock in the evening a second ship comes in sight on the port bow.  This time, instead of seeking to avoid her, Captain Spade signals an order by means of the apparatus above referred to, and resumes his course to the east—­which will bring him close to the said ship.

An hour later, the two vessels are only about four miles from each other.

The wind has dropped completely.  The strange ship, which is a three-masted merchantman, is taking in her top-gallant sails.  It is useless to expect the wind to spring up again during the night, and she will lay becalmed till morning.  The Ebba, however, propelled by her mysterious motor, continues to approach her.

It goes without saying, that Captain Spade has also begun to take in sail, and the work, under the direction of the boatswain Effrondat, is executed with the same precision and promptness that struck me before.

When the twilight deepens into darkness, only a mile and a half separates the vessels.

Captain Spade then comes up to me—­I am standing on the starboard side—­and unceremoniously orders me to go below.

I can but obey.  I remark, however, ere I go, that the boatswain has not lighted the head-lamps, whereas the lamps of the three-master shine brightly—­green to starboard, and red to port.

I entertain no doubt that the schooner intends to pass her without being seen; for though she has slackened speed somewhat, her direction has not been in any way modified.

I enter my cabin under the impression of a vague foreboding.  My supper is on the table, but uneasy, I know not why, I hardly touch it, and lie down to wait for sleep that does not come.

I remain in this condition for two hours.  The silence is unbroken save by the water that ripples along the vessel’s sides.