He held on in the doorway, and Captain MacWhirr, feeling his grip on the shelf inadequate, made up his mind to let go in a hurry, and fell heavily on the couch.

“Head to the eastward?” he said, struggling to sit up.  “That’s more than four points off her course.”

“Yes, sir.  Fifty degrees. . . .  Would just bring her head far enough round to meet this. . . .”

Captain MacWhirr was now sitting up.  He had not dropped the book, and he had not lost his place.

“To the eastward?” he repeated, with dawning astonishment.  “To the . . .  Where do you think we are bound to?  You want me to haul a full-powered steamship four points off her course to make the Chinamen comfortable!  Now, I’ve heard more than enough of mad things done in the world—­but this. . . .  If I didn’t know you, Jukes, I would think you were in liquor.  Steer four points off. . . .  And what afterwards?  Steer four points over the other way, I suppose, to make the course good.  What put it into your head that I would start to tack a steamer as if she were a sailing-ship?”

“Jolly good thing she isn’t,” threw in Jukes, with bitter readiness.  “She would have rolled every blessed stick out of her this afternoon.”

“Aye!  And you just would have had to stand and see them go,” said Captain MacWhirr, showing a certain animation.  “It’s a dead calm, isn’t it?”

“It is, sir.  But there’s something out of the common coming, for sure.”

“Maybe.  I suppose you have a notion I should be getting out of the way of that dirt,” said Captain MacWhirr, speaking with the utmost simplicity of manner and tone, and fixing the oilcloth on the floor with a heavy stare.  Thus he noticed neither Jukes’ discomfiture nor the mixture of vexation and astonished respect on his face.

“Now, here’s this book,” he continued with deliberation, slapping his thigh with the closed volume.  “I’ve been reading the chapter on the storms there.”

This was true.  He had been reading the chapter on the storms.  When he had entered the chart-room, it was with no intention of taking the book down.  Some influence in the air—­the same influence, probably, that caused the steward to bring without orders the Captain’s sea-boots and oilskin coat up to the chart-room—­had as it were guided his hand to the shelf; and without taking the time to sit down he had waded with a conscious effort into the terminology of the subject.  He lost himself amongst advancing semi-circles, left- and right-hand quadrants, the curves of the tracks, the probable bearing of the centre, the shifts of wind and the readings of barometer.  He tried to bring all these things into a definite relation to himself, and ended by becoming contemptuously angry with such a lot of words, and with so much advice, all head-work and supposition, without a glimmer of certitude.

“It’s the damnedest thing, Jukes,” he said.  “If a fellow was to believe all that’s in there, he would be running most of his time all over the sea trying to get behind the weather.”