The Famous Piltdown Hoax

Chemistry Oct. 1969

[21] At the turn of the century, paleontology, the study of ancient man, was especially exciting. Some 30 years before, Charles Darwin had proposed his theory of evolution, and the so-called missing links-fossil proofs that man evolved from apes-were being sought. In 1907, this search was given considerable momentum when the Heidelberg jaw was found, indicating that man as a species was older than previously supposed. This was the setting for perhaps the greatest hoax ever perpetrated in the scientific community.

The story begins when laborers, while digging in a gravel pit near Piltdown, England, found a few scattered pieces of bone. They or their employer realized the possible value of the pieces and presented them to Charles Dawson, a local amateur archeologist. Dawson verified antiquity of the bones, and said they were part of a skull, possibly human. He began to search for the rest of the skull, and in 1912, a jawbone was uncovered. Arthur Woodward of the British Museum verified that the bones were ancient, and further that the skull had human features and that the jaw was ape-like. But whether the jaw fitted the skull could not be determined-the point of attachment or joint on the jaw was missing.

This was practically stop-press news. An evolutionary link between man and apes had been uncovered! But in December 1912, when the discovery was announced publicly, the conclusion met with some opposition. Nevertheless, the opinion of an authority having the stature of Woodward could not be ignored, and, therefore, the fossils became known as the Dawn Man.

In 1915 another Dawn Man was found in a gravel pit adjacent to the site of the original find.

Uncovered in one stratum were a rhinoceros tooth of unquestionable age and a canine tooth and parts of a cranium having human characteristics. This supported the conclusion. The only remaining problem was placing the fossils in the evolutionary tree.

This became difficult. At first, Dawn Man was the evolutionary line, but during the 1930's, more finds of human-like fossils (Pithecanthropus - Java Man, Neanderthal, and Australopithecus) left Dawn Man isolated in the evolutionary sequence. He became an unsolvable puzzle. Perhaps he represented a line that had become extinct.

In 1949, this situation was complicated even more, when Kenneth Oakley said that age of the Dawn Man was only 50,000 years rather than 500,000 as previously estimated. He used fluorine dating, based on a finding made by Carnot, a French mineralogist, that bones and teeth accumulate fluorine from the soil. Their fluorine content can indicate their geological age. However, Oakley found that all the fossils found at Piltdown were of the same age. This supported the ape-man theory.

PIC

Courtesy Smithsonian Institution

From a few fragments scientists can often reconstruct a complete skull. Above, cast of Heidelberg jaw and a restored skull based on it. Below, restored casts of Piltdown jaw and skull. Dark areas correspond to original fragments found.

Such was the state of affairs in July, 1953, when a congress of paleontologists met in London. There J. S. Weiner of Oxford University overhead a casual comment that Dawson, who had a reputation for accuracy, had documented his find scarcely at all. Weiner did not believe either of two possible conclusions-that the fossils were in fact from an ape-man, or that a fossil of ape and man could be found side by side. Further, the likelihood that fossils of ape and man could be found together twice was even more improbable. [22] Hence, Wiener set out to find a better explanation.

First Weiner examined plaster casts of the fossils. The only truly human characteristic in the jaw was the flat wear of the teeth. All other features were ape-like. Surely, unless the teeth had been ground down to appear human, modification of muscle attachments should be present. Also, the canine tooth showed abnormally heavy wear for its age, unless it, too, had been ground down. The biting surfaces didn't even match! Furthermore, when Weiner ground down and stained an orangutan tooth with permanganate, it looked very much like that of the Dawn Man. Later, x-rays of Dawn Man showed that the roots of the teeth were not human!

Because of this evidence, authorities of the British Museum were persuaded to allow further testing on Dawn Man. Using improved testing methods, fluorine content of the jaw and three teeth turned out to be below 0.03%, indicating a fairly new specimen. But the cranium showed 0.1%, indicating late Ice Age. The fragments from both sites gave comparable results. Therefore, the jaw and cranium could not belong to the same individual!

Then more tests were done-iron, nitrogen, collagen, organic carbon, organic water, radio-activity, and crystal structure were determined. All of the tests verified the fluorine results.

These tests showed that the cranium was stained with potassium dichromate and jaw [sic] with Van Dyke brown, a color containing iron. According to Woodward, Dawson had applied the dichromate to harden the fossils. But why was the jaw stained with both iron and dichromate? Probably to match the cranium which fluorine dating had shown to be much older.

The initial estimate regarding age of the fossils was based partly on ancient artifacts found nearby. One implement was an elephant femur worked into a club. Experiments with fresh bone showed that it could not be worked, and that only the aged bone could have been shaped in that manner. X-ray analysis showed that flints associated with the find had been iron-stained, notably one found by Teilhard de Chardin, who had worked at the site. Inside, the flint is pure white, indicating that the stain had not been acquired by absorption from the soil throughout centuries. Also, animal teeth found at the site were not only stained, but of recent origin and inconsistent with known facts about life at that time in England.

And so Dawn Man, now known as Piltdown Man, was exposed as a forgery. Deliberately fashioned to resemble the missing link, he had been planted in the excavated areas. But by whom? All evidence seems to point to Dawson. Missing links were his special concern. He had an inventory of many fossils and was known to have experimented with staining. He lived in the area, knew of the Heidelberg find and of objections raised by the scientific community to his own find. Hence, he could plant specimens designed to cancel the objections. Further, although he had somehow gained a reputation for scrupulous investigation, it was discovered that his finds were not documented. Of course, the question of who designed the forgery is merely of academic interest now. But the lesson remains: Scientific skepticism often reveals the truth.