“And if you hit a mine?” I asked.

“You go up—­but you hadn’t ought to hit em’, if you’re careful.  The thing is to get hold of the first mine all right, and then you go on to the next, and so on, in a way o’ speakin’.”

“And you can fish, too, ’tween times,” said a voice from the next boat.  A man leaned over and returned a borrowed mug.  They talked about fishing—­notably that once they caught some red mullet, which the “common sweeper” and his neighbour both agreed was “not natural in those waters.”  As for mere sweeping, it bored them profoundly to talk about it.  I only learned later as part of the natural history of mines, that if you rake the tri-nitro-toluol by hand out of a German mine you develop eruptions and skin-poisoning.  But on the authority of two experts, there is nothing in sweeping.  Nothing whatever!

A BLOCK IN THE TRAFFIC

Now imagine, not a pistol-shot from these crowded quays, a little Office hung round with charts that are pencilled and noted over various shoals and soundings.  There is a movable list of the boats at work, with quaint and domestic names.  Outside the window lies the packed harbour—­outside that again the line of traffic up and down—­a stately cinema-show of six ships to the hour.  For the moment the film sticks.  A boat—­probably a “common sweeper”—­reports an obstruction in a traffic lane a few miles away.  She has found and exploded one mine.  The Office heard the dull boom of it before the wireless report came in.  In all likelihood there is a nest of them there.  It is possible that a submarine may have got in last night between certain shoals and laid them out.  The shoals are being shepherded in case she is hidden anywhere, but the boundaries of the newly discovered mine-area must be fixed and the traffic deviated.  There is a tramp outside with tugs in attendance.  She has hit something and is leaking badly.  Where shall she go?  The Office gives her her destination—­the harbour is too full for her to settle down here.  She swings off between the faithful tugs.  Down coast some one asks by wireless if they shall hold up their traffic.  It is exactly like a signaller “offering” a train to the next block.  “Yes,” the Office replies.  “Wait a while.  If it’s what we think, there will be a little delay.  If it isn’t what we think, there will be a little longer delay.”  Meantime, sweepers are nosing round the suspected area—­“looking for cuckoos’ eggs,” as a voice suggests; and a patrol-boat lathers her way down coast to catch and stop anything that may be on the move, for skippers are sometimes rather careless.  Words begin to drop out of the air into the chart-hung Office.  “Six and a half cables south, fifteen east” of something or other.  “Mark it well, and tell them to work up from there,” is the order.  “Another mine exploded!” “Yes, and we heard that too,” says the Office.  “What about the submarine?” “Elizabeth Huggins reports....”