“Want a certificate?  Here, let me have a feel what’s wrong.”  The Doctor interrupted his whiffing for a moment to reach forward and feel Nicky’s knee professionally, outside the thick sea-cloth trousers.  “Hurts, does it?  You’ve a nasty swelling there, my man.”

“It hurts a bit, sir, and no mistake.  If I could only have a certificate now—­”

“All right; I’ll give you one,” said the Doctor, and turned his attention again to the mackerel.

Before stepping ashore at St Martin’s, he pulled out a fountain-pen and scribbled the certificate on a leaf torn from his note-book.  Having with this and one shilling compounded for his trip, he said as he traced up his catch—­

“There, stick that in an envelope and post it.  You’re clearly not fit for service afloat till that swelling goes down.”

Nicky-Nan duly posted the certificate, which Dr Mant had characteristically forgotten to date.  After a week it came back with an official note drawing Nicky’s attention to this, and requesting that the date should be inserted.

“Red tape,” said Nicky.  He borrowed a pen from Mrs Penhaligon, and wrote the date quite accurately at the foot of the document.

Then, for some reason or other, his conscience smote him.  He put off posting the letter; and at this point again fortune helped him.  Word came to him by a chance wind that the staff of the Coastguard had been shifted, over at Troy.  Also (though he never discovered this) the Chief Officer of Customs, after returning the certificate, had left for his summer holiday.

So Nicky-Nan kept it in his pocket; and nothing happened.

The next year—­so easy is the slope of Avernus—­Nicky-Nan, who had felt many qualms over filling in a date which (though accurate) should by rights have been filled in by the Doctor, felt none at all in adding a slight twiddle of the pen which changed “1912” into “1913”; by which he escaped again, and again went undetected.

It had all been contrived so easily, and had succeeded so easily!  Everything said and done, his leg was worse.  Any doctor alive, if brought in, would bear witness that it incapacitated him.

Also any man, who looks ahead, will fight for the pension which alone stands between him and the workhouse.

With such arguments Nicky-Nan had salved his conscience; and his conscience had slept under them.

Now in a moment, with eyes fixed on the fatal handwriting, he saw every bandage of false pretence, all his unguents of conscience, stripped away, laying his guilt bare to the world.

An enemy was on his track—­one who knew and could call up fatal evidence.

The light in the window-pane had been growing darker for some minutes.  The morning had broken squally, with intervals of sunshine.  A fierce gust came howling up the little river between its leaning houses and broke in rain upon the bottle-glass quarrels of the window.