In the mad heat of last summer Lisa discovered that raspberry yoghurt is improved by the addition of Sandeman's Fine Old Ruby Port. Her method is to add a teaspoonful of port to the yoghurt, stir briskly, test, and so on ad lib until the required degree of enrichment is reached. She soon graduated to tablespoonsful, and then sloshing it straight in from the bottle, though in this case some finesse is required if the mixture is to retain its consistency. If it becomes too liquid, then Lisa's policy appears to be to drink it and start again...

When she discovered that I utilise empty yoghurt containers for mixing paints, Lisa's experiments were extended to visits to the studio. Today the local dairy has supplied orange yoghurt so she is trying vodka in place of port. While not materially affecting the flavour of the mixture, it certainly adds interest.

She pauses in mid-swig to ask what I am doing.

It just so happens that I'm carrying out an experiment of my own, standing on a chair, and dangling a paperback copy of Kasner and Newman's Mathematics & the Imagination from the end of a long piece of string.

– I'm waiting for this book to jump into my hand, I explain.

Lisa gives me a pitying stare and returns to her work.

– Then you've a long wait ahead.

– It could happen any minute, I protest.

– Not unless I give it a helping hand, bounces back the sceptical rejoinder.

– Don't you dare... you'll ruin everything. Just take my word for it. It's bound to happen sooner or later. All the facts of statistical mechanics and physical chemistry, not to mention the kinetic theory of gases and probability theory, support my belief. Molecules are always moving – they only stop when the temperature drops to absolute zero, and that condition prevails in the studio only in mid-winter – and this book is continually being hit by the molecules of air moving around it.

At this precise moment in time, the buffeting from above and below is about equal and cancels out so that gravity pulls the book down. But come the moment when the molecules pushing the book down happen to ease off, then kapow! the molecules of air pushing the book upward successfully counteract gravity, and the book leaps into my hand...

– Sheeeeesshhh... mouths Lisa, with eyes upturned.

I am stung by her obvious disbelief to make a wild claim.

– Well, it's even possible to forecast when it will happen. Since the probability lies between 1/googol and 1/googolplex, the book will definitely rise within a period of less than a googolplex of years...

– A googlewhich?

– A googol is merely a convenient mathematical name for a big number... ten to the hundredth power, or 1 followed by a hundred zeros. A googolplex is an even bigger number... ten to the googol power. It has been said that there wouldn't be enough room to write it out in figures, even if you put down a zero every centimetre of the way right out to the furthest star from Earth. But we're still dealing with a finite number, less than infinity, that mathematicians can throw about casually in calculations...

– How about a drink while you're waiting, comes a relaxed invitation.

– You're distracting me, I protest with all the dignity I can muster.

An hour later there are still no detectable results though the stiffness of my arm suggests that some air molecules have been doing their damnest to push the book to the floor. I give up and climb down from the chair.

The studio is deserted. The Blonde Presence has gone and so has the vodka.

A spreading multicoloured pool catches my eye and I become aware that several paint containers are slowly leaking their contents. During the mopping up I make a mental note to complain to Lisa that her Polish vodka is slowly dissolving the plastic yoghurt pots. ■