had already left Wood’s Holl two miles behind and Vineyard Haven Harbour was only some four miles further it seemed silly to turn back.  There was always the chance that the fog would blow off, besides.  Nevertheless Steve frowned dubiously through the moist pane ahead and, without saying anything of his fears to the rest, drew the throttle a few notches down and kept the Adventurer close to her course.  Behind, the Follow Me speeded up as well and the two boats hurried for where, out of sight in the grey void ahead, West Chop pointed a blunt nose to sea.

But it was a losing race, for ten minutes later Steve saw that the fog bank was rolling down upon them and from somewhere to the eastward came the dismal hoot of a steamer feeling her way along.  Joe, too, saw what they were in for and turned anxiously to Steve.  “That’s fog, isn’t it?” he asked.

Steve nodded.  “Get the fog-horn ready, will you?  We don’t want anyone bumping into us.  I’m going to slow down to six miles.  There’s too much water here to drop anchor in.”  He eyed the advancing fog distastefully and then shrugged his shoulders.  “You’ve got to learn some time, I suppose, Joe, and here’s where I learn to make harbour by the compass.  Now we’re in it!”

At that instant the grey mist enveloped them silently, chillingly.  Joe drew a long wail from the fog-horn and in response a similar but higher-keyed wail came through the fog from the Follow Me.  And at the same moment the other members of the ship’s company stuck inquiring heads through the companion ways.

“Hello,” exclaimed Perry.  “Fog!  Gee, that’s exciting!  Say, you can’t see a thing, can you?  Look, fellows, the boat hasn’t any bow!”

“Nor any stern,” added Han.  “You can almost taste the stuff.  Say, Steve, isn’t it hard to steer in a fog?”

“Not a bit,” answered Steve cheerfully.  “Steering’s perfectly easy.  The only trouble is to steer right.”

“To-o-ot!” said the fog-horn and was answered from astern.  Then somewhere to the south-eastward a siren sent a wailing cry, subdued by distance.  The fog settled on everything and shone on the boys’ sweaters in little beads of moisture.  The Adventurer seemed to be standing still, for, with nothing to judge by, progress was made known only by the slow lazy throb of the engine.  Even the water alongside was scarcely discernible.  Joe pulled the lever of the fog-horn again, and this time, beside the response from the Follow Me, an answering bellow came across the water.

“A steamer,” muttered Steve, peering uselessly into the grey void.  “She’s a good ways off, though.  Give her another pull, Joe.”

Again the Adventurer proclaimed her position but there was no answer from the steamer.  “She doesn’t seem very talkative,” said Phil.  “How fast are we going, Steve?”

“Six.”

“And how far is Edgartown?”