A key piece of evidence used to implicate Dawson as the hoaxer is based on his having applied a certain chemical to several of the skull fragments. Weiner asserts he did so as a deception – to color the fragments so they would match the dark, iron-stained gravels of Piltdown. There is, however, another, more plausible explanation.

Dawson freely admitted applying the material, potassium bichromate, and inadvertently darkening the first skull pieces he found at Piltdown – hardly the mark of a deceiver. He did it because he feared the pieces, having been waterlogged, would crack and flake on drying. In fact, he had written Woodward urgent letters asking advice on preservation techniques. (Potassium bichromate and gelatin provide a good mixture for hardening and waterproofing fossil bones.)

Coincidentally, Doyle was something of an expert on the use of potassium bichromate, having mentioned in his M.D. thesis its use in hardening and staining histological sections. Since Dawson and Doyle knew each other, it is reasonable to suppose that, while waiting for Woodward’s reply, Dawson consulted a helpful Doyle and followed his instructions. Wherever Dawson acquired his technique, however, his efforts to preserve specimens can scarcely be seen as deceit.

But there was another staining chemical found in Piltdown’s fossil fragments, iron sulfate. Dawson never said anything about applying this to the bones. Doyle, on the other hand, used sulfate together with potassium bichromate in hardening his biological specimens. He may well have added iron to these chemicals to darken the color and then applied the mixture to stain the bones before strewing them in the Piltdown gravels.

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This page was last updated October 18, 1998.