‘What’s a kilometre, Mr McCaskie?’ he asked blandly.

‘Multiply by five and divide by eight and you get the miles.’

I was on my guard now, and told a long story of a nephew who had been killed on the Somme, and how I had corresponded with the War Office about his case.  ‘Besides,’ I said, ‘I’m a great student o’ the newspapers, and I’ve read all the books about the war.  It’s a difficult time this for us all, and if you can take a serious interest in the campaign it helps a lot.  I mean working out the places on the map and reading Haig’s dispatches.’

‘Just so,’ he said dryly, and I thought he watched me with an odd look in his eyes.

A fresh idea possessed me.  This man had been in Gresson’s company, he knew German, he was obviously something very different from what he professed to be.  What if he were in the employ of our own Secret Service?  I had appeared out of the void at the Kyle, and I had made but a poor appearance as a bagman, showing no knowledge of my own trade.  I was in an area interdicted to the ordinary public; and he had good reason to keep an eye on my movements.  He was going south, and so was I; clearly we must somehow part company.

‘We change at Muirtown, don’t we?’ I asked.  ’When does the train for the south leave?’

He consulted a pocket timetable.  ’Ten-thirty-three.  There’s generally four hours to wait, for we’re due in at six-fifteen.  But this auld hearse will be lucky if it’s in by nine.’

His forecast was correct.  We rumbled out of the hills into haughlands and caught a glimpse of the North Sea.  Then we were hung up while a long goods train passed down the line.  It was almost dark when at last we crawled into Muirtown station and disgorged our load of hot and weary soldiery.

I bade an ostentatious farewell to Linklater.  ’Very pleased to have met you.  I’ll see you later on the Edinburgh train.  I’m for a walk to stretch my legs, and a bite o’ supper.’  I was very determined that the ten-thirty for the south should leave without me.

My notion was to get a bed and a meal in some secluded inn, and walk out next morning and pick up a slow train down the line.  Linklater had disappeared towards the guard’s van to find his luggage, and the soldiers were sitting on their packs with that air of being utterly and finally lost and neglected which characterizes the British fighting-man on a journey.  I gave up my ticket and, since I had come off a northern train, walked unhindered into the town.

It was market night, and the streets were crowded.  Blue-jackets from the Fleet, country-folk in to shop, and every kind of military detail thronged the pavements.  Fish-hawkers were crying their wares, and there was a tatterdemalion piper making the night hideous at a corner.  I took a tortuous route and finally fixed on a modest-looking public-house in a back street.  When I inquired for a room I could find no one in authority, but a slatternly girl informed me that there was one vacant bed, and that I could have ham and eggs in the bar.  So, after hitting my head violently against a cross-beam, I stumbled down some steps and entered a frowsty little place smelling of spilt beer and stale tobacco.