Irving: [... W]ould you estimate on the evidence in front of you approximately how big those dots are?
Van Pelt: I find it very difficult. I do not know exactly how the shadow runs.
[...]
Van Pelt: It is very difficult to determine the size of the objects, because of the way the shadow works. If one looks at the shadow of the chimney, one sees that the chimney really projects considerably out of the building, the shadow of the chimney.
[...]
Irving: Both the crematorium chimney and the protruberances on the roof which you think these dots are, would they all be vertical?
Van Pelt: Yes.
Irving: So they would all cast shadows in the same direction, at the same angle, would they not, if that were so?
Van Pelt: Yes, that is quite likely.
Irving: On this photograph they clearly do not cast shadows in the same direction. The smudges or dots appear to be first one way and then another?
Van Pelt: Yes, that is the indeed true.
[...]
Van Pelt: But I think that these dots show very clearly that there are four introduction devices in morgue No. 1, or four something on top of that roof.
Irving: Professor, I strongly suggest that is a major quantum leap to suggest that a dot which on the face of it is about 15 feet long on the roof of this crematorium building can have anything at all to do with the protruberances that you were talking about earlier, which at its largest extent in the eyewitness evidence that I have seen is of the order of 36 inches.
Van Pelt: Mr Irving, the whole of the width of what you call the alleged gas chamber I think is something like, what is it, a little less than 20 feet. So, if you look at the width of this room and you look then at the dots, we are certainly not talking about dots which are 15 feet wide. We are more looking at dots which are probably 3 feet wide.
Irving: I strongly disagree. They are over one quarter of the width of that roof in all their versions and manifestations on these various photographs.
Van Pelt: I am not going to argue at moment about the width.
Irving: Moreover, they cast no shadow.
Van Pelt: It is impossible to say what kind of shadow they cast.
[...]
Irving: What have you to say about the spacing of those smudges when you compare them with what I call the tar barrels on the roof in the other photograph? They are differently spaced, are they not?
Van Pelt: I cannot judge that. In the one photo we looking from more or less ground level at these boxes, and now we look more or less straight from above and it is impossible to come to any conclusion one way or another.
Irving: I disagree with you. Would it not be correct to say that in fact there is a very uneven spacing in the four tar barrels visible from the ground, whereas the smudges on the roof appear to be admittedly irregularly spaced but in a totally different way. Therefore, they have no connection whatsoever with the protruberances that are visible from ground level.
Van Pelt: I have no comment on that.
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