The Piltdown Puzzle
 Chapter Ten: The Piltdown Puzzle
"It's been a colorful fossil with all its faults. It's like a child that gives you a lot of troubleyou come to love it." Dr. Shapiro'New Yorker', December 5th, 1953.
For complexity and ingenuity, the elaborate Piltdown fraud has no parallel. Van Meegeren with his Vermeers, Thomas Wise with his pamphlets, are unrivalled in their own particular spheres, but no one has hatched the versatility of the perpetrator of 'Piltdown man', who seems to have been equally at home in the spheres of geology, anatomy, chemistry and prehistoric archaeology.
In elucidating the identity of the forger, the field of suspects is considerably narrowed by this versatility. He must had had enough geological training to enable him to stage his mis-en-scene in gravels of appropriate age to contain a 'missing link', which was supported by an intriguing assemblage of extinct fossil animals (some of which were gathered, apparently, from abroad). His knowledge of anatomy is shown in the way he broke the skull so that no two parts fitted together, giving free scope for individual interpretation in its reconstruction. No detail escaped his attention; he even manufactured minute 'nose bones' out of splinters from some animal's limb bone. He broke the lower jaw in the vital place where it fitted with the temporal bone of the skull, so that it was impossible to prove whether it did or did not belong to the skull. He appreciated the difference in wear on the teeth caused by a human and an ape's way of chewing and ground down the molars and canine tooth accordingly. By immersing the fragments in a solution  of iron sulphate (and chromate to hasten the process), he stained them to an appropriate shade of antiquity to match the flints in the gravel. Not only were the bones and teeth stained in this way, but also the 'implements', which were of sufficiently ambiguous workmanship to allow a certain elasticity in the age of their supposed maker, Piltdown man.
The forger had access to 'props' not easily obtainable, such as the jaw of a young female orang-utan and a human skull, probably of Neolithic age, which was so thick that it is almost certainly a pathological specimen. Most surprising of all the finds at Piltdown were teeth of a very rare elephant, unknown in England, but common in a certain site in Tunisia, which was unknown to the scientific world until 1946, nearly thirty years after the Piltdown finds. In other words, it seems possible that the forger or an accomplice had visited North Africaif not the site itself, at least perhaps Cairo where practically anything may be picked up in the junk shops.
In addition to being a globe trotter and a man of wide scientific knowledge, the forger was apparently well read. He produced precisely the right creature to fill the gap which was supposed to exist in man's evolutionary record according to the theories of the day. Darwin had supposed a common ancestor for man and the great apes would one day be found. Forty years ago (when the fraud took place), it seemed reasonable that such an ancestor would combine characteristics of both in his make-up. The timing too, was excellent, for not long before, a massive human jaw had been discovered at Heidelberg; its brain case would be expected to be of equal proportions, and the thick Piltdown fragments seemed to match it well. ...
 Although some of the discoveries were not made until several years later, it is convenient to list the more important of them together (for an explanation of the terms, see footnote). *
1908 (?) Part of the left parietal, said to have been given to Dawson by road menders
at Barkham Manor.
1911 (autumn) Part of left frontal, left temporal, part of occipital, and a piece of hippo
tooth, all found by Dawson.
1912 (spring) Dawson showed his finds to Smith Woodward.
(summer) Small piece of occipital found by Smith Woodward. Dawson found
three pieces of right parietal and, later, the mandible. He also discovered three
flint implements, several 'eoliths', a fragment of the tooth of an elephant
(Elephas planifrons ), one much rolled bit of the tooth of a mastodon, teeth of
beaver, deer, etc.
1913 (summer) Teilhard de Chardin found the canine tooth of 'Piltdown man'. Nasal
bones and turbinals found by Dawson.
1914 Bone 'implement' found by workmen in presence of Smith Woodward and
1915 Part of right frontal, part of occipital, and lower molar, all of 'second Piltdown
man' found by Dawson about two miles from Barkham Manor.
* Eolithscrudely clipped stones formerly supposed to be the earliest implements made by man.
Frontalbone forming the forehead.
Occipitalbone at the back of the skull.
Parietalone of a pair of bones forming the sides and top of the skull.
Temporalbone on each side of the head in the region of the temples.
Turbinalsmall cone-shaped bones forming part of the nasal region.
...  It is interesting now to read a passage from a book by the American professor H. F. Osborn, written in 1928. After a visit to the site, Osborn said he knew of no locality where fossil remains are so indistinguishable from the gravels. 'Under these conditions . . . the finding of the canine or eye tooth by Teilhard de Chardin indicated an almost hawk-like vision; finally, the unearthing of the two minute black-coloured nasal bones of the Dawn Man was almost a miracle.'
Teilhard de Chardin was born at Orcines (Puy de Dôme) on May 1st, 1881. He was educated at the secondary school of the Collège Saint Jesus de Mongré in Villifranche-sur-Saone, followed by one year of higher education at the Facult é de Clermont. In 1889, he entered the Company of Jesuits at the novitiate of Aix-en-Provence, and from 1901-2 studied literature at Laval (Mayenne). From childhood he had been interested in natural history, and his professor at Laval complained that his pupil's mind was never on his literary studies. His opportunity came between 1902 and 1905 while studying philosophy in Jersey, for there he had leisure to study the rocks of the island and he wrote his first scientific paper on their mineralogy for the publication of the Jesuit Society. He next went to Cairo, where he remained until 1908 as lecturer in physics and chemistry in the Collège de la Sainte Famille. ...
[149[ During the summer of 1913 the work was continued without much success until August 30th, when Teilhard found the canine tooth. In 1914 the discoveries were still fewer. And then, in 1915, Dawson found a second 'Eoanthropus' in another exposure of gravel some distance away from the original site!
Smith Woodward describes how this field had 'especially attracted' Mr. Dawson's attention and how they searched it together on several occasions without success during the spring and summer of 1914. But later, when the stones had been raked off the ground and brought together in heaps in the course of farming, Dawson was 'so fortunate as to find here two well-fossilized pieces of human skull, which he immediately recognised as belonging to at least one more individual of Eoanthropus dawsoni'.
Although Smith Woodward had searched the field with Dawson, it is believed that he was never shown the actual spot at Sheffield Park where Dawson discovered the fragments. Dawson told him of the find of a molar tooth (similar in type to those in the jaw), quite casually on a postcard dated July 30th, 19I5.
The discovery was not published until 19I7, when it was announced by Smith Woodward, after Dawson's death the previous year. The delay in publication of so significant a find would be inexcusable were it not for the fact that there was a war on. Even so, it seems strange that Dawson showed no eagerness to publicise his discovery himself in 1915.
 'If there is a providence hanging over the affairs of prehistoric man', wrote Osborn in 1928, 'it certainly manifested itself in this case, because the three minute fragments of this second Piltdown Dawn Man found by Dawson are exactly those which we would have selected to confirm the comparison with the original type.'
The bones included a fragment from the supraorbital (eyebrow) region of the frontal bone, a small piece of the occipital bone, and a left first lower molar. This particular tooth, and the frontal part, were not represented at all in the original finds; only the occipital fragment duplicated part of the first skull and seemed to show that the new finds could indeed be attributed to a second Eoanthropus.
This discovery of a second Piltdown man served to sway many who had been dubious about the association of the jaw with the skull of Piltdown I. The molar resembled the teeth in the mandible so closely that there seemed no reason to doubt that a second individual had been found with exactly the same characteristics as the first. As the American William Howells put it, 'It partly depends, of course, on what your credulity will stand. Mine winces at the notion of ape and man incongruously mixed in a single animal, but it wilts entirely at the idea of their being mixed by chance, twice over, in the Piltdown gravel.'
These were the last remains of Piltdown man to be found. Charles Dawson is said to have died from poisoning caused by septic teeth at the age of fifty-two, in 1916. Father Teilhard was serving as priest with the French Red Cross (and was awarded the Médaille Militaire and made Chevalier of the Legion of Honour). Only Smith Woodward was left to continue his patient and unrewarding search. 'I did a little more digging last month,' he wrote in 1921, 'but without result.' In 1938, Smith Woodward erected a monument to his friend Charles Dawson on the site of his discoveries at Barkham Manor; it was unveiled by Sir Arthur Keith. Sir Arthur Smith Woodward died in 1944, at the age of eighty, the day after he had  dictated the last words of his book The Earliest Englishman to his wife, for he was then blind.
The original specimens of Piltdown man were usually kept locked away in a safe in the Natural History Museum, produced on very rare occasions for the reverent gaze of privileged persons. The South African archaeologist, A. J. H. Goodwin, tells of how, in 1922 when he was doing a post-graduate course, Smith Woodward said to him: 'I will show you what few anthropologists have seen.' He led him into his room and produced the Piltdown fragments, resting on a bed of cotton wool. 'I was not permitted to touch them,' said Goodwin, 'though he turned them over carefully to permit me to see all views.'
Accounts have been given by two American anthropologists who were accorded the privilege of inspecting the original fragments; they came to very different conclusions. Osborn describes how, in 1921, Smith Woodward took the bones out of the safe and placed them on a table so that 'full and free opportunity was given for the closest observation and study '. At the end of two hours, Osborn came away convinced of the association of the skull and jaw. He says he was reminded of a prayer of his college days': 'Paradoxical as it may appear, O Lord, it is nevertheless true.'
Hrdlicka, one of the leading anthropologists of his time, describes how he studied the specimens 'for a good part of two days'. His first strong impression was one of normality. Later, however, as he handled the thick skull bones, he found them more and more impossible to reconcile with the much lighter jaw. "After prolonged handling of both the jaw and the skull", said Hrdlicka, there remained in the writer a strong impression that the two may not belong together, or that if they do the case is totally exceptional '.
Mr. Martin Hinton, a former Keeper of Zoology in the Natural History Museum, wrote in a letter to The Times after the exposure of the fraud in 1953: 'Had the investigators been permitted to handle the actual specimens, I think the spurious nature of the jaw would have been detected long ago.' In actual fact, as the above  accounts show, several investigators did examine the originals. Suspicions they might have had, but detection or proof of fraud would have been impossible without the aid of scientific tests.
* * *
The Exposure of the Fraud
During the second world war, Dr. K. P. Oakley, a young geologist and anthropologist of the British Museum (Natural History), was engaged in research on phosphate resources on the one hand, and on the geological aspects of dental fluorosis on the other, for the Geological Survey of Great Britain. In the course of this work, he came across a forgotten paper by the French mineralogist Adolphe Carnot, in which Carnot gave the results of analysis of fossil bones. of various geological ages from a number of different sites. He showed that there was a progressive increase in the fluorine content of bones with age (it is now known that Carnot duplicated a discovery made by the English chemist James Middleton fifty years previously, in 1844). Carnot's work was not taken seriously at the time, because it was found that the fluorine content differed not only with age, but that it differed also from place to place. Where much fluorine was present in the ground waters, buried bone naturally absorbed this element more rapidly than in places where there was little fluorine. Although the method could not be used for absolute dating, Oakley thought it might well prove useful in the relative dating of bones of different ages from the same locality.
With the aid of analytical chemists in government laboratories in Bristol and London, Oakley tested the fluorine content of a number of fossil human skulls. The percentage of fluorine was then compared with that of animal bones from the same sites, the geological age of these species being known. Oakley first mentioned this method of relative dating, and its possible application to fossil man, in a discussion at the Geological Society in February, 1943. Even before this preliminary announcement appeared in print, the application of the fluorine method to the  Piltdown bones was already being considered. This was revealed by Mr. W. N. Edwards after the final exposure of the fraud in 1953, in reply to an implication that the authorities had been tardy in their examination of the specimen. ('After all,' wrote Mr. Edwards, 'I was Keeper of the Geological Department of the British Museum, with both Dr. Oakley and Piltdown man under me!')
In 1949, the decision was taken to drill into the precious bones, not without considerable misgivings. The responsibility was heavy and it can well be imagined that the instructions were to extract as little of the material as possible. ...
When the Piltdown fragments were first analysed, in 1949, at least 20 milligrams of bone was needed as a sample to ensure accurate results. But owing to the supposed uniqueness of the specimen, it was necessary in some cases to work with samples of only 5 mgm. It was believed that with samples larger than this, the experimental error would not be greater than 0.1 per cent fluorine; but when the samples were smaller, as they were in the case of some of the bones and teeth tested, then the error might well be twice as great. This experimental error was to have very significant results, though it was not suspected as the time.
Animal teeth from the Piltdown gravels known to be of Lower Pleistocene age (which many believed to be contemporary  with the human remains) were found to contain 2 per cent fluorine. The skull and jaw of Piltdown man, however, contained only between O.1 and 0.4 per cent. The teeth were reported to have 'less than 0.1 per cent fluorine'. It was obvious, then, that Piltdown man was considerably younger than the Lower Pleistocene mammals, which included a rare type of early elephant known as Elephas planifrons to be mentioned again later.
No appreciable difference was found in the fluorine content of the skull and teeth of Piltdown man; this was due to the margin allowed for experimental error. The figures obtained, though on the low side, were not impossible for an Upper Pleistocene age. Bones and teeth of beaver and a hippopotamus molar found with the human remains contained a similar low percentage of fluorine and these animals were undoubtedly Upper Pleistocene. Since there was no question at that time of some of the specimens being more modern than Upper Pleistocene, there the matter ended. The problem of the association of human skull and jawbone had not been settled one way or the other. All that could be said was that there was no apparent difference in age between them, which rather strengthened the case for their belonging to the same individual.
It seemed that Piltdown man must be nearer 50,000 years old than 500,000 as had been supposed by some. Although this was sensational enough to scientists, to the general public the difference between five figures and six was of no particular interest, and the matter was soon forgotten. Four years went by and scientists were more unhappy about Piltdown than ever. Most of them dismissed the problem as insoluble, but a few continued to be absorbed by it and gave it their serious attention.
One of those most deeply concerned was Professor (now Sir Wilfrid) W. E. Le Gros Clark, F.R.S., one of the greatest experts on anatomy in the world today. Naturally he had casts of the Piltdown  fragments in his Department at Oxford, and he and his assistant Dr. J. Weiner would often puzzle over them together. One of their greatest worries was that the molars showed a 'human' rather than anthropoid type of wear (the wear is quite distinctive owing to the different movements of the jaw in chewing). This feature was, in fact, practically the only one that did not conform with a typical modern ape's jaw.
Dr. Weiner started experimenting and found that 'artificial abrasion of the teeth of a chimpanzee, combined with appropriate staining, produced an appearance astonishingly similar to the Piltdown molars and canine'. In August, 1953, he suggested to Dr. Oakley that the Piltdown jaw and teeth were those of a modern ape. Oakley jumped at the idea as a possible way out of the dilemma. He immediately saw that this might be the explanation of certain things that had puzzled him during the 1949 fluorine test, such as the whiteness of the dentine beneath the superficial colouring of the teeth (which he had noted in his report, published in Nature in 1950).
Permission was given for the fragments to be re-tested and, once Piltdown man had shed his aura of extreme antiquity after the results of the 1949 tests were made known, drilling would this time be carried out more boldly. In the meantime, too, more refined methods had been evolved which made it possible to detect smaller quantities of fluorine in bone, so that the experimental error was reduced considerably.
While the mandible was being drilled to obtain a sample for testing, Oakley turned to his assistant and asked: "Do you notice anything?" "Yes," came the reply, "there's a smell of burning". With memories of our last visit to the dentist, we can imagine only too well what he meant. Fresh teeth or bone would smell of burning certainly, but one would hardly expect this of fossils. The sample drilled out of the jaw consisted of tiny shavings, as in the case of modern bone. But when the bones of the skull were drilled in the same way, the sample consisted of powder, as is obtained by drilling fossil bone, and there was no smell of burning.
 A point that has not, perhaps, been sufficiently emphasised is that when the samples were
submitted to the Government Chemists for fluorine analysis, they were contained in little glass tubes, each with a number. The chemists who did the tests had little idea what the samples were or where they came from.
The results were satisfactorily conclusive: Piltdown cranial bones 0.1 per cent fluorine (the same as the minimum fluorine content of the supposedly local Upper Pleistocene bones); mandible and canine tooth less than 0.03 per cent; molar less than 0.04 per cent (the molar of a modern chimpanzee was found to contain 0.06 per cent). Such accurate results in the detection of minute quantities of a substance speak highly of modern chemical techniques, only a few years ago they would not have been possible.
Other evidence all tied up very nicely. It had been found by experiments in the U.S.A. that nitrogen contained in the protein of buried bone is lost very slowly, so that often a determination of the nitrogen content of different bones at the same site gives an approximate indication of their relative ages. The Piltdown jaw and teeth contained as much nitrogen as does modern bone, while the skull fragments had considerably less.
No less than eight lines of evidence pointed to the fact that the jaw was modern and that the canine tooth and molars had been ground down artificially. The staining of the canine tooth was found not to be due to iron, as was the case with the other bones and flints from Piltdown, but was 'a tough, flexible, paintlike substance' in the words of the first report on the Piltdown fraud (authorities at the National Gallery subsequently proved that it was oil paint, probably Vandyke brown).
One of the most curious facts to emerge during the rigorous chemical tests to which the fragments were subjected was the presence of chromate, not only in the original skull fragments, but also in the mandible. After Dawson found the first pieces of skull, he is known to have dipped them in a solution of bichromate of potash with the mistaken idea that this would harden them. This he did before showing them to Smith  Woodward. From published accounts it is clear that the latter pointed out to Dawson that such a solution would not harden the specimens and that it was useless to apply it. The jaw was found later that summer, and chromate staining could not have been applied to the jaw after its 'discovery' without the knowledge of Smith Woodward. It was without doubt applied before the jaw was planted.' "Curiouser and curiouser," said Alice.' What was the point of applying chromate? The answer was not known in the autumn of 1953 when the first Piltdown report was published, but subsequent experiments have made it clear, as will be explained later.
The results of their investigations were given by Drs. Weiner, Oakley and Le Gros Clark in a Bulletin of the Geology Department of the British Museum (Natural History) which was published on Saturday, November 2Ist, 1953. The same morning, The Times devoted a whole column to the exposure of the fraud, with a photograph of the offending jaw and canine tooth. The news was exclusive to this newspaper. This time, unlike in 1912 when Piltdown man was first introduced to the world, the news did not leak out before the authorities intended it to.
The evening before the news was announced, Dr. Oakley gave a lecture on the dating of fossil remains in Africa to the Royal Institution. Although he did not confine himself entirely to Africa, not a word was said about the Piltdown jaw. The next morning I left the house early before reading The Times, and later rang up the Museum and asked for Dr. Oakley, meaning to congratulate him on his talk the evening before. The switchboard operator said immediately, 'If you are ringing up about the skull, Dr. Oakley is not answering any questions.' I assured her I was not ringing up about any skull, but did not pursue the matter, as I assumed he was, up to something and obviously busy. While I was still wondering what it could be, I opened The Times! From some of the distortions which subsequently appeared in the press, some frankly jocular, others written in all seriousness,  it is clear that the decision not to grant an open interview before the true facts had been published in a reputable newspaper was justified. Piltdown man was accorded as much publicity as he had been in 1912. Headlines such as 'The Missing Link Hoax: Experts were spoofed by a monkey's jaw', or ' A Lawyer made a Monkey out of Scientists' made a great popular appeal.
The only person who adopted rather an extraordinary attitude towards the whole thing was Mr. A. T. Marston, a London dentist and the discoverer of the famous Swanscombe skull (which now becomes the oldest in Europe). He granted a series of interviews to reporters anxious for the low-down denied them at the stern portals of the British Museum. Perhaps some of his words were distorted, but from the reports it appeared that he had told the authorities the truth about Piltdown all along, but that they had refused to listen to him. 'I told Oakley and Le Gros Clark about this in 1936 and the matter was first referred to by another expert in 1913,' he is reported to have said. What matter? That the jawbone resembled that of an ape? Smith Woodward pointed that out in 1912, and experts have been saying it ever since, so there was nothing new in that. But nobody, I believe, ever suggested that it was the mandible of a modern ape, certainly not Mr. Marston, who always insisted (and still does) that it belonged to an ape far more ancient than the human skull fragments.
The only suggestion made by anyone before 1953 that the jaw might be a fake, so far as I know, was made by Sicher in 1937 in an obscure dental paper. ('Zur Phylogenese des menschlichen Kiefergelenke', Zeitshrift für Stomatologie, Heft 4, 35, 1937, p. 247.) After discussing whether the skull and jaw could belong together, he remarked: 'Einheitlichkeit oderFalschung? ' (unity orfalsification?).
In one interview, Mr. Marston confessed: "This is the happiest day of my life. For nearly twenty years I have been publishing articles saying the bones came from an ape. I became interested in Piltdown when I discovered the Swanscombe skull in 1935. It is estimated as 300,000 years old and now becomes the oldest  in Europe." How was this age estimated? By comparing the fluorine content of the skull with that of Middle Pleistocene fossil mammals from Swanscombe (both yielded 2 per cent fluorine). And yet at the meeting of the Geological Society on 25th November, after Oakley had presented the evidence for his conclusion that the jaw and teeth were modern, Mr. Marston pursued his old arguments that the jaw was very ancient without once referring to the chemical tests which had been instrumental in establishing the age of his Swanscombe skull.
The authors of the report on the 'Solution of the Piltdown Problem' were careful to make no reference to the possible perpetrator of the fraud. The announcement in The Times of November 2Ist, however, mentioned the possibility of Dawson being connected with it. After describing the two witnesses of the fraudulent finds (Sir Arthur Smith Woodward and Father Teilhard de Chardin), the report says:
'Thus two witnesses of the highest character either found, or helped to find, the bones now known to be spurious and it is hard to resist the conclusion that the jaw and tooth had been put there, by some third person, in order that they might be so unimpeachably discovered. If that third person were to prove to be Charles Dawson, it would be but one more instance of desire for fame (since money was certainly not here the object) leading a scholar into dishonesty.'
At the Geological Society's meeting mentioned above, Marston tried to read a letter 'to clear Dawson's name', but the President ruled that this was not part of the business of the Society. He had to insist firmly on several occasions (a) that nobody had suggested that Dawson was implicated except the press; ('that the meeting was concerned solely with the geological aspect of the case and that it was not part of the evening's business to clear anyone's name. The following day another statement from Mr. Marston appeared in a newspaper:
'Those who besmirch the memory of Mr. Dawson are  hiding their own sycophantic servility to the traditions of the British Museum. It is the British Museum who for years have been playing a hoax on the public by presenting the Piltdown skull, the so-called "missing link", as something authentic. Now they have knocked the guts out of their own argument.'
If they could have found a way to knock the guts out of this particular argument long ago, I suspect that the British Museum would have been only too delighted. But science demands proof. As the science editor of the New York Herald Tribune wrote, 'Scientists may make mistakes, but when they find them they are quick to announce them.'
There were others besides Mr. Marston who leapt to the defence of Dawson in the press, but he had his critics as well as supporters. One of the most outspoken was Mr. L. F. Salzman, the Sussex archaeologist, who wrote: 'I have said all along it was a forgery. Why? Because I knew Charles Dawson. The burning desire of a small-town solicitor to become famous was probably the cause of the hoax.' Perhaps the eminent archaeologist Sir Mortimer Wheeler got nearer the truth than anyone when he wrote simply: 'Charles Dawson must have known something about it.'
Let us suppose for a moment that it was Dawson who was primarily responsible and see what motives we can find. The desire for financial gain, the commonest reason for fraud, can be ruled out entirely. There was no possible pecuniary reward to be derived from the gravels at Barkham Manor other than their value for road-making. Neither was Dawson the sort to indulge in practical jokes. He held no grudge against the experts; on the contrary, he held them in respect, possibly even awe. He was serious minded, a Fellow of the Geological Society and of the Society of Antiquaries, well respected for his various valuable contributions to science.
Nothing could be more natural than his desire for fame, however, and this appears to be the only possible motive. He  often attended meetings of learned Societies and heard experts discussing important discoveries. Probably few people who have attended such meetings have not indulged in the secret wish that they should find themselves in a position to address their colleagues and announce some sensational discovery that would make the professors gasp. Especially is this the case with those who are passionately absorbed in a particular subject, as Dawson undoubtedly was.
There is another possible motive that must be considered: the desire to prove a cherished theory. It has often happened that all the evidence seems to point to a particular hypothesis, yet the tangible object to prove it is lacking. This was the case with Boucher de Perthes, who knew that somewhere must be the bones of the men who made the thousands of hand-axes he had found, yet they remained obstinately elusive. He searched for them persistently throughout his long life, and when at last they seemed to have turned up, what could be more natural than that he should accept them uncritically ?
'Diogenes' wrote in Time and Tide :(December 5th, 1953) 'Now Piltdown man was in fact never discovered. He was not a fact, but a hypothesisa hypothesis constructed out of a bit of skull, a jawbone and a tooth. Since the Origin of the Species the search for intermediary forms has gone on. Whenever some tiny fragment of bone etc. has been found, scientists have made the most of it.' The possibility, then, that Piltdown man had been concocted to disprove religious disputes over evolution could not be ruled out. This motive is easier to forgive than when the desire is simply fame. A would-be celebrity is despised, yet a fanatic can be regarded with tolerance and even sympathy. Fanaticism, however, does not seem in keeping with Dawson's character.
Seven months after the meeting of the Geological Society when it had first been announced that Piltdown man was a fraud, the scientists concerned with its exposure presented a mass of fresh evidence (discussed in the next chapter). The rooms  of the Geological Society were again packed to capacity on June 30th, 1954, when six speakers discussed the matter. The fraud had been found to be far more elaborate than had been suspected at first. Some of the fossils planted at Piltdown appeared to have come from abroad, for instance.
Then, in November, 1954, it was announced that a number of specimens from Dawson's private collection, now housed in the Hastings museum, had turned out to be forgeries. The collection included a quantity of flint implements supposed to have been found in Sussex; investigations proved that some of these had come from Denmark, others from New Zealand, and others again had been manufactured by Flint Jack! Amongst the questionable specimens, too, was a small axe head which Dawson claimed to have found in a slag heap at Beauport, near Hastings. This was an important Roman iron-working site and from it Dawson collected a small statuette which he claimed to be the earliest example of cast iron in Europe. At the time (1893) the statuette had been accepted by the Society of Antiquaries, though doubts had been expressed by some authorities. It now seemed clear that it was most probably of comparatively recent date.
It was also alleged that Dawson's monumental History of Hastings Castle, published in two volumes in 1909, had been drawn largely from a manuscript written by William Herbert, who had carried on excavations at the castle in 1824. Dawson made some acknowledgment to Herbert's work in his book, but he did not make it clear that his own researches were based almost entirely on those of his predecessor.
Whether Dawson's knowledge of anatomy, geology, anthropology, archaeology and chemistry was enough to enable him to see the incredible Piltdown fraud through by himself seems doubtful. It is more likely that he had an accomplice. There is always the possibility that someone is still alive who does know the full facts and may yet come forward with the truth.
 Chapter 11: The Detectors: Prehistoric
Is the forger of the future now doomed? It would seem that he has little chance of eluding the attacks of Geiger counters, X-ray spectrography, and electron-microscope photography capable of enlarging his crime 30,000 times. It was by modern scientific methods such as these that the Piltdown problem was finally solved. Sir Gavin de Beer, Director of the Natural History Museum, said: "These methods will not only make a successful repetition of a similar type of forgery virtually impossible in the future, but will be of further value in palaeontological research. The exposure of the hoax is a gain to science."
* * *
The Piltdown Exposure
It was Sir Gavin de Beer who opened the serious business of the evening at the meeting of the Geological Society on June 30th, 1954. He summarised the evidence which had been assembled since November, 1953 (when the Piltdown jaw had first been denounced as a fake) as follows:
(1) The jaw is that of an immature orang-utan. Microchemical tests have confirmed that it is recent, supported by X-ray evidence and results obtained by examination under the electron-microscope.
(2) The black coating on the canine tooth is oil paint.
(3) The so-called turbinal bone of the nose has been shown by its texture to consist of thin fragments of some animal's limb bone.
(4) All the associated flint implements from Piltdown were artificially iron stained, and the presence of chromium on one of them has been confirmed by chemical tests.
 (5) The famous ' bone implement ' was shaped by a steel knife.
(6) The whole of the associated fossil animal bones was planted, and radioactivity tests suggest
that some of them came from abroad. Some of the fossils, such as beaver teeth, were fixed into lumps of gravel with gum.
(7) The human skull fragments and some of the fossil animal bones are partly replaced by gypsum,
as a result of their treatment with iron sulphate, oxidised in some cases by a chromium compound. The object of this treatment was to stain them the same coIour as the gravel.
(8) Not a single one of the Piltdown finds genuinely came from Piltdown.
Professor Le Gros Clark then spoke on the anatomical features of the jaw and teeth. The flat wear of the molars, he said, is characteristic of an early stage of human attrition (wear) but is never seen in apes. Another feature which had puzzled them was the shortness of the roots of the molars, (also a human feature), as seen in X-ray photographs-taken by Underwood in 1913. New photographs, however, reveal that the roots are in fact much longer than appeared in 1913 and that they are typical of an ape's molar.
The wear was a bit too flat, he pointed out. The dentine should wear down below the level of the enamel margins, but if it had been filed, the surface would be fresh. Nominally the outer 'cusp ' (or small projection) is more worn than the inner cusp, thus exposing more dentine on the outer than the inner side. But in the case of the Piltdown molars, more dentine is exposed on the inner side, a phenomenon which had never been seen before (Plate 3). By means of lantern slides, Professor Le Gros Clark showed criss-cross parallel scratches on the tooth caused by filing; he also pointed out that the enamel tends to split vertically along the margins when filed, and that this had happened on the Piltdown molars. Although the canine is that of an immature ape, the whole thickness of the enamel had been removed completely, in order to reduce it to an appropriate 
size. More fantastic still, the tooth has a stopping! For plastic material was found in the pulp cavity plugging up a hole.
By permission of the British Museum (Natural History)
Plate 3. A. Molar of Australian aboriginal, showing typical human flat wear. The outer cusp is worn more than the inner.
B. Molar from the Piltdown mandible, ground down artificially. The inner cusp shows
more wear than the outer.
C. First and second molars of an orang-utan.
D. The same after grinding in the laboratory to resemble wear on the Piltdown molars.
[see p. 164
Dr. J. S. Weiner (who first suggested that the jaw was a fake) then demonstrated the jaw of a female orang-utan which he had 'maltreated' in the same way as the forger (Plate 4),* and also showed a filed and stained orang canine tooth beside the original. They were practically indistinguishable. He pointed out that 20 grains of sand had been introduced into the canine, which rattled like a pepper box. No very fine sand had got in, as it certainly would under natural conditions, but all were coarse grains which had obviously been inserted.
* The mandible illustrated in Plate 4 (B) was prepared by Mr. L. E. Parsons, Dept. of Geology, British Museum (Natural History).
By permission of the British Museum (Natural History)
Plate 4. A. The Piltdown mandible.
B. Mandible of a modern orang-utan prepared in the library to resemble the Piltdown jaw and then artificially stained.
[see p. 165
The most dramatic moment came when Dr. C. F. Davidson of the Atomic Energy Division of the Geological Survey described his part in the drama, an 'academic effervescence' as he put it. He is concerned with the study of the radioactivity of phosphate rocks and has followed up Lord Rayleigh's observation (1908) that bones and teeth often show marked radioactivity owing to their absorption of uranium from ground waters. The amount of radioactivity depends on the age of the fossil, the permeability of the surrounding beds, and the uranium content of the rocks in the neighbourhood. An advantage over the fluorine method of relative dating is that none of the fossil material is consumed during tests for radioactivity. Also a bigger sample is assayed, perhaps as much as one square inch of the surface. It has been found that radioactivity of bone is greatest in sands and gravels, lower in clays and silts, and lower still in limestone. Another point to be considered is that lower values are usually obtained from enamel (which adsorbs uranium with great difficulty) than from dentine and bone.
The radioactivity of the Piltdown skull fragments compared with that of the Swanscombe skull was found by Mr. S. H. U. Bowie to be in the proportion of about 1: 27. In three of the Piltdown cranial samples there was slightly more radioactivity, which is possibly due to potassium chromate having been used  to stain them. The conclusion is that the bones are Post-Pleistocene rather than Pleistocenecertainly later than the gravels in which they were contained. There was found to be a great range of radioactivity in the fossil animal bones. That fossils of several ages were present in the Piltdown collection had already been shown by fluorine analysis.
The most puzzling fossil from Piltdown is the tooth of a very rare elephant known as Elephas planifrons, found by Father Teilhard de Chardin. This species had never before been identified with certainty in Britain, and the Piltdown specimen was discovered to be thirty times more radioactive than any other early Pleistocene fossils investigated from this country. It was also compared with specimens of E. planifrons from several foreign countries, including France, Italy, India and North Africa. In one case only was the radioactivity as high as in the specimen from Piltdown: in a tooth from Ichkeul, near Bizerta in Tunisia. Dr. Davidson emphasised that this did not necessarily mean that the Piltdown elephant tooth came from this site; but the indications are so strong that it would be pure pedantry to avoid this conclusion.
The next speaker was Dr. G. F. Claringbull, of the Department of Minerals in the Natural History Museum. By X-ray analysis, he had detected the presence of the mineral gypsum (calcium sulphate) in the human skull fragments and fossil animal bones from Piltdown, but this could not have been derived from the gravels themselves. Tests by the Soil Survey and the Counties Public Health Laboratory showed that this mineral was present only in infinitesimal quantities in the soil, while in water from a local well there was only seventy parts sulphate per million. From experiments, Dr. Claringbull and Dr. M. H. Hey found that the mineral could have been introduced by means of an acid solution of iron sulphate; this solution had evidently been used to stain the bones a dark brown colour. Here was indisputable proof that the human skull bones as well as the beaver, deer and hippopotamus remains had been planted at Piltdown.
 Dr. Oakley gave the remaining evidence: first a report from Professor J. T. Randall, F.R.S., and Dr. A. Martin of the Physics Department of King's College. Under their electron microscope, they had seen that intact fibres of collagen were present in the jaw, showing without doubt that it was modern. A photograph of the bone magnified no less than 30,000 times showed these organic fibres clearly. The skull fragments, he said, were sub-fossil when stained: of Neolithic age at the oldest. The thickness of the bone suggests a pathological condition, such as can be seen, for instance, in a Patagonian skull in the Natural History Museum.
Dr. Oakley then proceeded to solve the mystery as to whether more than one skull was involved in the complicated make-up of Piltdown man. The right frontal bone of 'Piltdown II' (found two miles away from the original site) could have formed part of Piltdown I, with which it agrees in thickness. But its chemical composition seems to be nearer that of the thinner occipital fragments. found with it. Detailed analyses have shown that this resemblance between the two pieces of 'Piltdown II' is almost certainly due to their having received the same artificial treatment, which differed from that given to Piltdown I (presumably the forger had perfected his chemical techniques during the interval). The fluorine/phosphate ratio of the bones is not likely to have been affected by treatment with iron sulphate and in this feature the frontal bone of 'Piltdown II' agrees with Piltdown I rather than with the occipital placed with it. It is concluded, therefore, that the frontal once formed part of the original skull, but that the occipital was part of a different skull from another site.
All the flints from Piltdown taken to be ancient implements had been iron-stained artificially. One of them, that which was found in situ by Father Teilhard de Chardin, also contained a trace of chromium. It is thought that chromate was used to hasten the process of staining with iron sulphate. A chip removed from this particular flint showed that the brown staining is entirely superficial; below the surface, the flint is white.