Before joining Mrs White’s class, I had never heard anyone called a gomeril and I have yet to hear the word again or see it in print. I assume it was offensive and Scots, so I owe her for expanding my native vocabulary.

Mrs Glenmuir had a stoop, doubtless from half a century of bending over weans with a kind of fierce benevolence. On the day John Sculler said “shite” a little too loudly when she was talking about worm casts, Mrs Glenmuir’s erse was a full three seconds behind her nose as she left the room to get the headmaster.

Her voice wrecked by two generations of staffroom smoke, Mrs Glenmuir could make a unique noise of derision: “Oooooooooorgh!” It was like a large, hollow steel pipe sliding off the back of a lorry. Whether she made this noise on the day primary 7 were berated for not knowing where the source of the Belstane Burn - Carluke’s answer to the Nile Delta - was, I cannot recall.

Nor can I remember what were the precise motives that drove my friend David Brown and me to mount an expedition to find this aqueous holy grail.

Perhaps we were a pair of sooks. More likely, we wanted to show her that we could do it, that the young of the day weren’t homebound layabouts who spent too much time watching ITV, though an irrational dislike of the commercial channel was one of Mrs White’s peculiarities.

Mrs Glenmuir’s chief eccentricity was using bicarbonate of soda in water as a universal panacea. One Saturday, David and I set off along the banks of the burn. It was a warm day. I took off my jumper and tied it round my waist, unaware that I would never see it again.

After a mile, a spoil heap hove into view. Behind it was a large grass banking with a strange metal structure visible on top. Feet clad in sandals, with what appeared to be rubberised brown sugar for soles, fought for grip as we raced up the slope. Cresting the hill we found the amazing truth: the source of the Belstane Burn was a nearly dried up reservoir.

We played there for a while, running around the puddles on the bottom and edging our way along the metal structure that had once been some sort of gantry. Not since we discovered a deep pit with two old cars and a sheep’s skull in it had we made such a find.

There was a bit of a discussion as to who had actually been first to see that it was a disused reservoir but that faded and we began to speculate on the suitability of the place as a hiding place for the pound;1,000 stolen that week from one of the town’s factories.

On arriving home, we were met by my father who listened to the story of our discovery and then pointed out that nobody had known where we were for four hours. He was not hard on us. I suspect we had been behaving exactly as he had at that age.

On the Monday, we told Mrs Glenmuir that we knew the source of the Belstane Burn. She too listened with interest, and it became clear that when she last had gone there herself the reservoir had not been dried up. Indeed, I got the impression that it might not have been built at the time.

Clearly, she had felt no compulsion to continually revisit the spot.

Perhaps it was something you did once, then moved on to finding the source of Jock’s Burn or the Coldstream Burn.

I went back a few times, most recently a couple of weeks ago just before we were due to go to France on holiday. My son (ex-P7) was restless and needed some kind of physical activity, both to distract him and make him sufficiently tired for the early night a 3am jaunt to the airport the following day would necessitate.

We took our mountain bikes and discovered a track that hadn’t been there in 1972. Climbing the slope again, everything suddenly wound back 34 years and I remembered the excitement of that tantalising pre-discovery moment before we knew what was over the crest.

Looking back on the trip, I do have a confession to make. Not once did I check to see whether or not the coltsfoot was in bloom.