I don't know when all this business of electrovalent methods of combination started, but Roper must, in those late nineteen-thirties, have known more than most schoolboys knew, and chemistry teachers for that matter. Not that Father Beauchamp knew much; he'd been learning the subject as he went along. What Roper said, I remember, was that the sodium atom had only one electron on its outer shell (nobody had ever taught us about outer shells) but that the chlorine atom had seven. A good stable number, he said, was eight and very popular with the constituents of matter. The two atoms, he said, deliberately came together to form a new substance with eight electrons on the outer shell. Then he said: 'They talk about holy numbers and whatnot – three and seven and nine and so on – but it looks as though eight is the really big number. What I mean is this: if you're going to bring God into chemistry, as you want to do, then eight must mean a lot to God. Take water, for instance, the substance that God made first, at least the Bible says about the spirit of God moving on the face of the waters. Well, you've got six outer electrons in the oxygen atom and only one in the hydrogen atom, and so you need two of those to one of oxygen to get water. God must have known all this, and yet you don't find eight being blown up as a big important number in the teachings of the Church. It's always the Holy Trinity and the Seven Deadly Sins and the Ten Commandments. Eight comes nowhere.'

'There are,' said Father Beauchamp, 'the Eight Beatitudes.' Then he had a brief session of lip-biting, not sure whether he ought to send Roper to the Rector for blasphemous talk. Anyway, he let Roper alone, and the rest of us for that matter, bidding us read up the stuff in our books. A twitch started in his right eye and he couldn't stop it. It was Father Byrne in the dormitory all over again.