I was actually in charge of it. I mean I had 60 submariners in my first job actually, I had 60 submariners under me, but of course I was 24 by then. I mean I’d been in the war, I went to Cambridge when I was... no, wait a minute, yes, I was quite into my 20s. I wasn’t all that young actually. Anyhow, I ran that experiment and one of the problems was recording what went on for a 10-hour period. We were 10 hours in this pressure chamber... it was actually built by Haldane, Haldane’s original apparatus which was down there which we used and I had the problem of recording what the submariners did and the mistakes they made as the CO₂ increased and the oxygen diminished. Of course you start doing damn silly things and the only recorder we had at that time was a strip of paper with pens on them, and it went wiggle, wiggle, wiggle along the paper, and you ended up with a mile of paper, literally, which you had to read off with a ruler recording the times and what happened, you see, each pen representing one particular sort of an event. I thought to hell with that, so I invented a digital recorder which I called THOTH, T-H-O-T-H, which was the Egyptian name of a god of language and wisdom, you see, and so I shot back to Cambridge and I spent about a month building this amazing machine which was really fun, it really was. Shall I tell you roughly what it was like? It was based on a palentype dictating machine. It had a keyboard and then it made letters, but you could press any numbers of letters at the same time and they came out in a row so you could get combinations of letters, unlike an ordinary typewriter. I had solenoids which pushed these keys down, then I recorded time with a thing like a mileometer on a car but with printing typeface on it so this was twiddling around continuously and I had an old RAF clock for that actually which pulsed it and it went round and round like this, and then it printed. So when something happened this thing went clonk and then printed a load of letters on the paper plus the time coded with this thing, you see. The paper was stationary until something happened so instead of recording on miles of paper, like an EEG, it was all there as a neat record, you see, so it was a digital recorder, and I think it could have been the first actually. It certainly wasn't available at that time. Now, of course it would look Heath Robinson in the extreme but it was an attempt at least to make a manageable thing.

But of course what actually happened was, it took such a long time making this thing, getting it to work properly, that there was a lot of displacement activity went on and I got so interested in my recorder that I probably put less effort into actually getting the results on the submarine experiment than I should have done, you know, it was tricky. But it did have an effect, they actually redesigned the submarines, and they redesigned them so that two chaps got out at once which a) speeded it up, and b) it meant that if one of them passed out, which you did because you suddenly took oxygen that can make you sick, and then you could choke and so on in the escape chamber, so whether that was a result of our experiments I don’t know but we advocated that it should be redesigned to get two chaps out at once and this did happen. So possibly we had some tiny affect, I don’t know.

[Q] But not as a result of THOTH?

Not really, no. I mean THOTH did actually get manufactured. I’ve been amazingly unsuccessful getting any of my alleged inventions onto the market but THOTH was actually made. It was called the Gregory-Russell Recorder, Russell, not Bertrand Russell, another Russell, was actually a fairly wealthy man who owned a small instrument company and he made it and then it was actually developed by the Cambridge Instrument Company and they made it for a time as well. Of course, we miniaturised it and it was quite a neat device in the end, but then of course it got superseded by computers. This was way before computers were available. But it was quite fun doing that.

I think there were lessons there actually. I mean in a way I think I deserve credit or points for actually having the energy to build a completely new device to solve a problem. On the other hand, it wasn’t exactly the right thing to do in the middle of a big experiment where 60 submariners were involved and they wanted to get the results. On the other hand, would we have got the results if we’d had all this measuring to do off miles and miles of paper? You know what I mean? It’s a tricky one, isn’t it, really?