Other people's arcana: the cinema organ

When I was a child, and there wasn't much on the telly, sometimes I would be up early on a Sunday morning, before the rest of the household had stirred, and I would watch the Open University. It was invariably someone demonstrating mathematics and I just loved letting the incomprehensibility of it wash over me.

People are passionate about all sorts of different things. Most of those passions I don't share; many I can't even comprehend; some I have an interest in; a curiosity about. But whatever it is you're obsessed with, I get it; I respect it; I admire it. I am passionate about narrow boats (ok, a small subset of them). Other people are passionate about trains, or buses, or the Archers, or Scott Walker - so that I don't have to be (my brain would explode). And I am very, very glad that there are people out there whose passion is cinema organs. Because without them, we wouldn't have any, just as we wouldn't have steam locomotives or big Woolwiches. And they are such extraordinary, marvellous, and almost pointless, things.

They don't transport you from A to B; they don't provide clean water; a Mighty Wurlitzer never, ever, carried goods around the country; you can't even take one on holiday. They provide music, for entertainment - just as countless other instruments and electrical and electronic devices can. They do it at great cost, in terms of space, time and money. If they were animals, they would long be extinct. They are complex, massive, delicate, expensive, greedy, scary... and quite fabulous.

Here is (are?) the arcana. This 'simple glossary' is, in fact, a failsafe way to recreate that Sunday morning Open University feeling. And - on a serious, and professional, note - brings home just how easy it is to forget that something familiar and easy to you (me), whether that be historic narrow boats or Marxist theory, is a foreign language to the uninitiated. Fortunately for me, I don't have to learn it; I can just revel in it. And that's before we've even heard the organ played. That's just the poetry of the naming of its parts.