Well, meanwhile of course, other things were going on in the lab, and I clearly had to think of a theme which would be big enough to allow me to use this first month's results, but which would not interfere with other work that was going on in the lab, on interhalogen compounds. And I chanced on the idea that a catalytic agent that was well known was boron trifluoride, like aluminium chloride, it is good at what was called Friedel-Crafts catalysts. And there were some fashionable theories at the time which said that was due to ionic intermediates, and I thought, well, if there are ions there I should be able to find them with my techniques of working under vacuum, high resistivity, but if there is a conductivity, I can measure it, and study it. So I thought that was a good thing, and Emmy approved of that, and typically with Emmy, he said, 'Do you know how to make boron trifluoride?' And so I said, 'Well, not off the top of my head', and he said, 'Well, look it up'. And so... he didn't say it quite so bluntly, but I looked it up, and it was not a difficult prep, but would mean making a bit of apparatus, and handling fluorine, but that was off because I didn't want to handle fluorine; that is a very aggressive thing. So there were other things, of using chlorides and calcium fluoride and things like fluoroborates, which would give the required product.

And so I built this apparatus, and made some of it, and... that is a gas, I might say, at room temperature, is boron trifluoride. And when I'd done this, he said, 'Well done, that didn't take you long. Here's a cylinder of the stuff'. And I wasn't best pleased, I have to say, but looking back on it, of course, it was Emmy's way; if you're going to use a compound, know how to make it. And if you've made it well, okay, don't waste time on it, you're not going to learn anything by making litres and litres of this gas, I have some here. Because he was a consultant with a particular firm which was making fluorine and was making boron trifluoride also, down at Avonmouth near Bristol, and he gave me that. So that was let off the hook, and we can continue the boron trifluoride story later.