Dear Dr Roth.
During the 1988 Zuendel trial, apparently, you allowed the possibility that HCN might penetrate damp and porous brickwork. But you also proposed as “possible” a sealant reaction that might prevent such a penetration. During the Errol Morris film interview you put it more strongly: it would “probably” penetrate no deeper than one tenth the width of a human hair. In his expert report Professor van Pelt takes you to mean something yet stronger than probable. “In other words, if one wants to analyze the cyanide concentration in a brick sample, one should take a representative sample of the surface, 10 microns thick, and no more.” If the sealant reaction was an established certainty, that does sound like the proper test. If it is merely a “probable” hypothesis then surely the correct way to test it would have been to take samples “the size of a thumb” and examine the surface and non-surface separately.
In extenuation of your concept Richard Green has assimilated it to graduated saturation. I am not sure I understand this. Throw a bucket of water on a mattress and the soaking will be wetter nearer to the surface. But that would hardly mean that the mattress was sealed. You do specify a very precise infinitesmal depth of 10 microns; thus far and no farther. Pulverising a sample from such a sealed wall would indeed be a dilution, not merely an averaging out. The Lipstadt trial judge treated this 10-micron hypothesis as scientific truth which had not been “controverted”, as did Evans in his popular book Telling Lies about Hitler. Yet the expert chemists Green and the Polish IFRC never seek to defend the core idea, even though it would have suited their purposes. David Irving did in fact “controvert” the claim, by posing the obvious and pertinent question. Why did the sealant reaction occur in the homicide chamber but not the Fumigation chamber? Justice Grey ignored this question, and the Errol Morris film was careful not to raise it - even though the whole discussion turns on the vast discrepancy between quantities of total cyanide residue in the two cases.
The massive presence of cyanide residue in the walls of the fumigation chamber was preceded by a massive presence of cyanide gas. To the lay mind, that looks like a clear of case of cause and effect. The clue is in the word “cyanide”. Most of these massive residues consist of “iron blue”, the stuff that can endure. The Polish IFRC refused to measure total cyanide, they say, because they could not imagine the “physico-chemical process” by which all this kind of iron cyanide might have got there. It might all have been a coincidence - an explanation involving blue paint was briefly hypothesised and then forgotten. I am glad that ships’ doctors of old did not wait for an understanding of underlying “physicochemical processes” before they assumed that citrus fruit might possibly prevent scurvy. On the other hand, to postulate the positive existence of 10micron surface reaction, you mighte be obliged to imagine some underlying physicochemical processes, since I have heard of no empirical evidence for such a cause and effect. Your imagining of such a process may be the only evidence in its favour. Have you published anything on this?
Yours etc
[Gwypaine]