A man at Speakers’ Corner told a sad story; “When I was a young lad goin’ to school in Dublin long ago.” he said, “I learned trigonometry. Do y’know what trigonometry is?” I kept my head down. Of course I know what trigonometry is, but I have a mortal fear of street performers of any kind. Didn’t I give some of the best hours of my young life to Tan a over 2, Sines and Cosines, Logs and Antilogs? I even painted the Cosine page in my log tables red, to avoid a tendency to read the Cosine instead of the Sine. That could result in my space probe failing to rendezvous with the comet, Giotto, by several million miles and probing the Bog of Allen instead. ‘It’s Tan a over 2. Stupid boy!’ I never quite cracked the language of mathematics. Napier filled a whole book with page after page of numbers and it became a best-seller. Pure genius. ” It’s all about angles and triangles,” explained the man. “I learned how to measure the height of any tree or a lighthouse or a skyscraper. It was amazin’. I decided to get a job measurin’ lighthouses, but when I left school I found out that all the lighthouses in the world had already been measured. That cured me of ambition. I’ve never worked a day in me life since then”.
As a child, I suspected that Rockabill was a ship. It has a chimney. It has a tender for the coal, just like a steam engine. It definitely moves, shunting up and down the horizon, depending on where you are standing. You need to keep your eye on it to see how it moves. Walk along the coastal path and it follows you, sometimes hiding behind the islands and then slipping out suddenly to surprise you with a new vista. I painted a picture of it and was roundly abused by a man who could see it when he was shaving every morning. “Where’s the gap?” he challenged me. “There’s a gap between the two rocks.” “Not where I was standing,” I replied lamely. “I was further to the south. Everything depends on your point of view.” He snorted derisively. “You’re wrong, you know,” he insisted. “There’s a gap.” There is a gap. A German U Boat sat up on that gap at low tide to effect repairs. It then went on to torpedo the mailboat Leinster with great loss of life. My father missed that boat, because he went on the beer. Who says that beer is bad for your health?
How could you do trigonometry anyway, with all those noisy neighbours? The rocks are covered by clouds of kittiwakes, terns and gulls, shags and cormorants. Look at your man showing off, the king of the castle. Little guillemots bobbed and dived on the calm surface of the water. There is abundant guano, often deposited in elegant triangles, the apex pointing to the nest. The British War Office appointed the artillery branch of the army to begin the great Ordnance Survey of Ireland. Ordnance relies on mathematics for accuracy. They began at Poolbeg Lighthouse in Dublin Bay, fixing the Ordnance Datum (OD) at a low spring tide and triangulated from that point, covering the whole island with a web of triangles. They then went on to anglicise all the place names, e.g. Skeheenarinky. It sounds like gibberish. It was Sceachín an Rinnce , the little thorn bush of the dancing—The Little People dancing at midnight in the moonlight. Be wary of the Little People. There are stories and myths in the old Irish place names, if you have the time and patience to tease them out. The Ordnance Survey nailed everything down. Now they use GPS and satellites to keep everyone in their sights. Even the OD has moved to Donegal. We have come up in the world.
Alice took us around the rock in a gentle curve. The islands swam from one point to another. The birds screamed at our intrusion. Perhaps they knew that Mike was about to catch some of their fish. We spliced the main brace to christen Michael’s new boat. A porpoise rolled on the surface. He shrugged and went below. Porc pisces —sea pigs? A gannet dived like white lightning. We noted a few brown jellyfish drifting languidly in the tide. Alison and Margaret took time out. Where else would you rather be?
I looked out this morning to check on that gap. The Rockabill was gone. There was a sea mist. Maybe, of course, it had merely gone walkabout. There was a time when it warned us of fog. Waw wah, waw wah, like a sick cow. It was a comforting sound when you lay in bed at night. Someone was keeping watch. Then it changed to Woop woop, woop woop. It had become a destroyer, steaming out of harbour to hunt for U Boats. Now it is silent. There is no need for watchers on the tower or foghorns to talk to the ships. All is electronic and of course, infallible.
There is a groove on the garden wall where the lighthouse keepers rested their telescope. They focussed on the white wall of Flower and MacDonald’s coal yard. I was talking to a lady about this one time, when suddenly, to my surprise, she went into a spasmodic dance, waving her arms about like a mantis. I thought it might be because of some hypnotic power that I might have over women—but no. “What was that all about?” I asked. “I was saying goodnight to my Daddy,” she said. “We used to talk by semaphore at the the coal yard wall.”
How the image in the lens, of his little girl with her flags, must have warmed his heart , during his lonely vigil on Rockabill.