So you see, so before I actually developed the theory of three dimensional imagery construction we already had understood that what you saw on the electron microscope was a projection of the structure by making models of the kind that I've just illustrated on the... on the board.

[Q] This also has been seen with TMV with the optical diffraction.

Oh, yes, yes, I've forgotten about that. I also introduced optical diffraction where you took an electron micrograph of a periodic object and you sent a parallel beam of light onto it. And it gave you basically a diffraction pattern, which you could deduce the repeating features. That was done optically and it was the first time and sort of rather obvious. I think I actually arose, got to that because I was, this time I was a teaching fellow of Peterhouse, my college in Cambridge and I was teaching optics among other things as well. And so I must have... must have had a... jump from the optical diffraction... By this time, this was now by the 19... middle '60s, '65, '68, and so looking back on it, it's hard to disentangle the different strands which fed this. It was interplay of the project to understand virus structure... and the... trying to learn how to use the electron microscope to understand what the pictures were. And the real point was that the electron microscope had a large depth of field, people say depth of focus, but the correct word is depth of field; so everything in the line of view is projected like an X-ray image. And that was the first-time people mentioned that and the way to do that was take a series of pictures until we had been taking... what had been done was, when we were building models we interpreted the different views as particles lying in different rotations, different orientations. And so, why rely upon them, why not take a specimen and tilt them in different orientations. And we put this to great effect, and I think we were the only lab in the world that was... well, we were the only lab in the world that was doing all this. And we were able to interpret not only virus pictures but others as well and other things as well. And there we met with a lot of opposition from the electron microscopists certain professional electron microscopists. There was a meeting in 1960... '50, I think it was Turkey in 1969, and we published a paper, DeRosier and myself, who came to work with me on this image reconstruction as we called it. In 1969 there was a meeting of the electron Microscopy Society of America where a man called [Lorenzo] Sturkey called the whole thing a load of crap, that's what he said publicly, I wasn't there. But David DeRosier, who was my visiting post-doc was there, and because at that time they thought that you couldn't solve the structure by electron microscopy because of multiple scattering. Because these are fairly strongly scattering objects, but we showed very clearly that it was single scattering that was basically dominating all this. This took many years to establish, so in the end, we did establish three-dimensional electron microscopy which I would like to have called it. But that could be misinterpreted because the people called three-dimensional electron microscopy the way that you could build up a structure in a series of sections. People cut sections of tissues or particles and built them up place by place, and that was called three-dimensional electron microscopy.