Episode 13

Drake’s Brass Plate Part 2: Maximum Absurdity

Welcome to the Poison Room, a podcast about the consequences of writing things down.

Today we’re finishing the story of the unintentionally convincing forgery of the Drake Plate. Here’s a brief recap: the Drake Plate is an artefact mentioned in three Elizabethan sources, with slightly varying details and questions surrounding their reliability. It was purportedly hammered to a post, along with a sixpence, in whatever California bay Drake stopped at during his circumnavigation of the world. It claims the land for Elizabeth and England, and proclaims that the indigenous people totally consented to this.

In 1937 Herbert Bolton, a prominent academic and respected scholar on the early history of the American west, published an article claiming that this important artefact has been found. His claim lacked any backing of relevant authorities, and no scientific testing has been done on the plate. The plate was found by Mr. Shinn when he stopped on a road somewhere in Greenbrae due to a flat tire. Whilst scouting for the perfect picnic spot, he spied the plate, and decided to pick it up to fix his car with. When he went to do that he noticed some detail on the plate and partially cleaned it. A friend recognised the word ‘Drake’ and suggested he take it to Bolton, who immediately recognised it as Drake’s brass plate, because this was a topic he’d got a particular obsession with. He got his friend Alan Chickering to raise the money to purchase the plate for the University of California. They paid today’s equivalent of $65,000 for it.

The plate had possibly been found three years earlier near Drake’s Bay, but the guy who’d found it put it in his car and forgot about it for a week. He supposedly rediscovered it when he was driving near Greenbrae, and for some reason known only to him, just… chucked it out the car. The site where he claimed he chucked the plate is just over half a mile from where Shinn found it. Some people still aren’t sure what to make of this part of the story, but given Caldeira was driving, and it was three years later when he reported it, half a mile doesn’t seem outside a margin of error for the exact location he chucked it, and his boss confirmed the story.

Back to Bolton. He was part of a quaint secret society called E. Vitus Clampus. They were (and still are, actually) a group with an interest in early Californian history, and set up plaques at prominent historical sites. They also liked having a jolly good time, which included playing light-hearted pranks on its own members.

It was members of this group who had made the plate in order to prank Bolton. Unfortunately, they didn’t count on Bolton buying it hook, line, and sinker. It wasn’t supposed to be a convincing fake. The academic community had doubts about the authenticity of the plate, and a couple of articles appear, pushing for a more rigorous analysis of it. The Clampers made a couple of subtle attempts to push Bolton to realise it’s a fake, but he didn’t take the hint. Then they tried a very not subtle approach of publishing a book that literally described how to detect the hoax. Bolton still did not take the hint. He’d stuck his reputation on the line for this plate, and he’s sticking to his claim.

So that’s where we’re at. Bolton and some of his colleagues have thrown scepticism out the window and are doubling down on the claim that the plate is real. But his boss at the university is getting a bit worried by all the very good questions being asked about the plate, and the lack of scientific testing. Bolton and Chickering reassure him and claim that they’re absolutely trying to get it tested, it’s just so gosh darn hard to find someone with the right skill-level.

Bolton’s article proclaiming the discovery of the plate was published in March 1937. Well over a year later, in December of 1938, Chickering and some others finally publish a more detailed report on the plate, which they’ve finally managed to have run through some scientific tests. Hooray! So you know last episode I told you it was going to get even more absurd? Yeah. This is that.

The guys who conducted the tests were Colin Fink and Eugene Polushkin. They state that they can’t give a certain answer to the question of how the plate itself was made. They describe it as being hastily, and not very well made. The thickness of the plate has far more variation that you’d expect for brass made at the time, though the variation is largely due to many small indents made all over the plaque.

But they can reveal that the plate had been cut away from a larger piece of brass due to chisel marks around the edges. If you remember, the plate had indeed been cut away from a larger piece of brass. But not by a chisel. It was a guillotine shear. In their defence, despite being made with a shear, the hoaxers did rough the edges up. Fink and Polushkin include photos of the edge of the plate, and it’s not absurd to describe it as looking like it was made by a chisel and then neatened up by hammering the back flat. Photos on the twitter. Link to the relevant tweet in the show notes.

The hole for the coin was also chiselled. And they checked that an Elizabethan sixpence would fit too, giving details of the actual coin they used – a sixpence from 1564. They even include a photo and everything (1938: 8-9).

What about whether the brass was rolled or not? If you remember, rolling would indicate modern manufacturing methods – old brass was hammered flat instead. Well… they think that the evidence suggests it wasn’t rolled. Basically the shape of some of the impurities suggests to them the plate was hammered rather than rolled (1938: 17). Not that this could in any way distort their findings or anything, but the piece of metal they use for the analysis of this is the tip of one of the pieces bent back to make the hole for the sixpence. I mean… why would using a highly warped piece of the metal make any difference?

They note that there are cracks in the plate which are characteristic of old metal. They do not do anything to see if any other method could produce such cracks (1938: 17). They note that there’s corrosion, which is unsurprising, but they don’t seem to do any tests on how long it would take the level of corrosion detected to occur. They don’t compare it to old brass in this instance, and they don’t do anything to rule out whether the corrosion could have been artificially sped up (1938: 18).

They also looked at the patina. The artificial patina that the pranksters had applied after inscribing the plate with Drake’s message. Luckily, because the back of the plate hadn’t been cleaned, they had material to work with. They checked the whole plate carefully to see if they could find any corrosion-free spots that would indicate a more recent creation date, but they found none (1938: 9-10). But they also note this… ‘black deposit’ covering most of the plate. They discover it’s made of two layers. The top layer, containing ‘small inclusions of red and brown minerals’ was easy to remove, but the black layer underneath was stuck pretty fast. Even after examining it, they can’t figure out what this ‘black substance’ is. But they can tell you it’s not water soluble! They also rule out that it’s some sort of lacquer or resin. They test it for chlorine, but there is none, and test it for sulphur, which it does contain. So… whatever it is, it contains sulphur minerals (1938: 12-13). Good to know. But! They find something more interesting after heating part of the patina. They’re pretty sure there’s calamine in it (1938: 13). If you remember, Haselden noted that calamine is what you’d expect from Elizabethan-era brass.

Fink and Polushkin also went and got some scrapings of patina from authenticated brass objects of the time, and achieved pretty similar results. Ultimately, they conclude that all indications point to a genuine patina produced over centuries, rather that something artificially made (1938: 13). They could find no evidence that an artificial patina had been applied (1938: 10). We can only imagine the levels of disbelief the hoaxers are reaching when they read this.

Our scientists also note that some ‘organic fibres’ were found in the grooves of the lettering, but they’re lying ‘loosely’ on top, and not embedded in the patina. They claim that these fibres were “undoubtedly” deposited in the grooves during cleaning. Yeah, not ‘possibly’ or even ‘probably’ but undoubtedly. Which is only a conclusion you can reach if you’re already ruling out any other modern interference with the plate. To claim it’s undoubtedly from the cleaning, you have to somehow rule out any other potential source. You have to be somehow certain that they couldn’t have come from someone’s clothes as they were handling the plate at any point. They just do not have the required evidence to support this claim. One might perhaps start to doubt their objectivity.

They also examine some plant tissue found in the grooves made by the creation of the hole for the sixpence. They conclude that it is also indicative of a very old plate, because they plant cells were mineralised, which is a process they say takes a very long time. In fact, they say, finding such mineralised plant cells in the cavities of ancient metal always provides unquestionable proof of authenticity (1938: 15). Put a pin in that argument, we’ll come back to it later.

Next, they talk about the writing. And this is another one of those things that just makes you go ‘… seriously?

An interesting detail which we observed in the lettering was the “parallel lines,” a series of thin, parallel grooves located near many of the letters. In most cases these lines were parallel to the letter grooves. Sometimes the lines were so close to each other that two or three of them could be counted in the width of one millimetre. The closeness of these lines to each other and their strict parallelism indicate that they could not have been made by hand one by one. If they had been made with a hand chisel (which is most probable), a special holder for the chisel fastened to a bench might have been used... Such parallel marks can be made today with a modern pneumatic tool but not readily with a hand chisel. We were not able to duplicate such parallel lines on a piece of modern brass using a hand chisel and we found no explanation for these parallel lines in an old treatise on methods of engraving as practiced in this time; but upon consulting Mr. S. V. Grancsay, an expect on armour at the Metropolitan Museum of Art, New York City, he stated that parallel lines such as we observed in the plate were occasionally found on old brass armour. It is also possible that, due to limited equipment of the machine shop on board Drake’s ship, some unusual, homemade, mechanical device was used in cutting the letters into the plate. The chisel may have been securely fixed over the plate and the plate moved about after each groove had been cut.’ (1938: 10-11)’

So, basically: there are these parallel lines on the plate that we cannot duplicate using tools available at the time, but which are easily made with modern tools. We couldn’t find any evidence in historical sources of a technique that would produce these results, but we found one guy at the Met who said he’d seen these kind of marks occasionally on brass armour, and if we hypothesise that the engraver Macguyvered a rig that we have no evidence existed at the time, then we can claim that it was most probably made by a hand chisel! Whew! Close call. Almost had to accept that this evidence might point to a forgery. Oh, and if you didn’t think that was bad enough, they have one more thing to add about the engraving:

It was surprising to us to find that some of the grooves still had sharp, well-preserved edges, but this could be attributed to the energetic cleaning of the surface before we received the plate. (1938: 11)

So… ‘we were surprised at how sharp some of the edges are but we’re literally not even going to mention the possibility that this could indicate a modern forgery, and instead just offer an explanation that allows us to maintain that it’s legit!’ Cool. Good scienceing, there, guys.

After that, they talk about some indentations made all over the plate, seemingly with a tool or weapon, most of which seem to have been made after the text was written. And once again, their commitment to objective science is staggering.

On cursory examination they appear to have been made by scooping out the brass with a sharp tool, perhaps with a round-edged chisel. The presence of deep flow lines in the bottom of the large indentations and the absence of a corresponding bulge on the back of the plate may easily lead to this conclusion. But when an experiment was made by us with a modern brass sheet by striking its surface with a sharp pointed steel hammer in oblique, slating fashion, indentations similar to those on the plate were produced. On account of the low angle of the inclination of the strokes, no bulge was produced on the opposite side of the sheet. (1938: 11).

‘Sure you can make these marks using a chisel, but if you get a steel hammer and strike it at the right angle, that also makes similar marks!’

And if you think that wasn’t bad enough, they go on to add that:

It is possible that the indentations on the plate were made by the Indians who were afraid of a mysterious or hostile power of the plate and after the departure of Drake tried to destroy the plate by striking its surface with their tomahawks; they were not familiar with the toughness of metals. 1938: 11)

Excuse me whilst I take a moment to figure out where to even start with this.

Got it. Let’s start with the racism. Now, if you remember from last episode, Bolton actually suggested that the movement of the plate could be explained by indigenous people carrying it round with them or even wearing it because they just revered it that much. He provided no evidence to explain why this might be a reasonable scenario. Now these two walnuts are suggesting that the marks on the plate can be explained by indigenous people attacking it because it was evil. And in another article, published in 1957, a guy called Walter Starr, who had actually gone with Chickering and Bolton to see where Mr. Shinn had found the plate, suggests that Greenbrae was the original site of the plate because the indigenous people would just be so scared of it and stay away from it because it was taboo (Chickering, Farquhar, & Starr, 1957: 32).

It’s almost like none of them have a clue about what the indigenous people thought of the plate, and are just guessing in ways that support their ideas. Huh.

Next, didya’ notice that the two tools they tried – a chisel and a hammer were both made of metal. And didya’ notice how at the end there, they said that the indigenous people were unfamiliar with metal? And how it was probably a tomahawk what made the marks? Now, they did actually test to see if similar marks could be produced by a stone tomahawk, and they did manage to make some such marks. But they’ve also made those marks using two tools that the Miwok people Drake met did not have access to.

Do ya’ see the problem here? They’ve literally proven that these marks can be made with modern tools. And yet! They don’t even acknowledge that therefore their evidence here is inconclusive. No. Instead they just focus on how it could be used to support their pet theory. Seriously. If I were sitting at a table right now, I’d flip it.

After this they move on to talking about the composition of the metal itself. They detect an amount of impurities in the plate characteristic of old metal (1938: 16). Now, some of these impurities have an ‘unusual colour, brown or red’. And they don’t actually know what it is, because they didn’t have a big enough sample to work with, but! Somehow, they’re still feel ‘justified’ in saying that you don’t find this in modern brass. They don’t say why they feel justified in saying that. They didn’t say if they inspected any modern brass (1938: 17). But the colour matches with calamine, which is what you want to find in old brass, so hey! Colour match is good enough, right? Not like there are any other compounds that could produce those colours.

They make another point, and I’m simplifying here, but basically, they state that the metal in the plate isn’t quite fully mixed – there are still parts where you can detect copper and zinc than aren’t quite fully mixed. You don’t get this at all in modern brass, apparently (1938: 20).

Using spectrographic analysis, they found magnesium and silver. Which could provide a useful clue, because old brass contains much higher amounts of magnesium that modern brass, and the copper of Drake’s time would be more likely to contain silver, which would therefore also appear in the brass. However, contrary to their expectations they found very little magnesium and so little silver as to be insignificant. But! The amount of magnesium they found is still more than you’d expect to find in modern brass. The plate was 0.01% magnesium, whereas according to the books they read, modern brass doesn’t contain more than 0.002% magnesium. Note that they test neither old nor modern brass to compare the silver and magnesium levels with.

Anyway. Ultimately, they acknowledge that the only part of their spectrographic analysis that supports an old date for the plate is the amount of magnesium found, but they don’t let that bother them (1938 22). Put a pin in this point, too.

There are some other tests they do, and basically, their ultimate conclusion is that it’s legit (1938: 25). We can only imagine how our hoaxers felt on reading this. And this report kind of becomes the final word on the Drake plate. No one really publically questions it.

There is one article by William Hume-Rothery published in 1939 that raises some questions about the report. He points out that there is no Elizabethan parallel for the forms of some of the letters that appear on the plate, then he points out that Fink and Polushkin didn’t actually do anything to rule out the possibility that, even if the brass is old, the engraving could still be modern. He points out that there’s conflicting evidence in the letters themselves – the presence of the black material in the grooves of the letters versus the sharpness of some of the edges of the grooves. Apparently he doesn’t think ‘oh it was probably the vigorous cleaning that made them sharp again’ is a good argument (1939: 54).

He also criticises the fact that the sample of metal they used for their analysis was from the tip of part of the metal that had been cut to make the hole for the coin. I.e.: a part of the metal that’s particularly warped, or, as Hume-Rothery puts it, subject to ‘intense local distortion’ that might affect their results (1939: 54).

Hume-Rothery thinks that the strongest claim Fink and Polushkin can actually make is that their results ‘show clearly that the brass is not obviously modern’ (1939: 55). Which is a far weaker claim than the one they did make. But Hume-Rothery’s not pushing the idea that the plate is a hoax, he just suggests some more tests that could be done to clarify details of the analysis and rule out some other possibly explanations for certain things (Hume-Rothery 1939: 54-55).

The paper goes largely ignored. The suggested tests aren’t carried out. In fact, no more tests were carried out for several decades. Also in 1939, you’ll be pleased to know, Chickering finally manages to find a single Elizabethan manuscript that spells ‘herr’ with a double R (1939: 251-53). So that obviously settles that question. Obviously.

What did the Clamper’s think of this report? I can’t say, but whatever they thought of it, they only thought it for a few years, because in the early forties Barron, Dane and Clark, the three main hoaxers, all died without the hoax being discovered. Bolton himself died around a decade later, in 1953.

In 1957 Chickering and two other historians write another article, giving people interested in such things an update on what the situation is about where Drake had originally landed. The first paper, by Francis Farquhar mentions that Drake’s Brass Plate is still a source of controversy, and that quite a few notable figures doubt it’s authenticity. He even states that:

There are those who claim to know that it is a forgery. One story has it that a man named Clark and the late George Barron, one-time curator of the De Young Museum, conspired to produce a forgery and that the plate in question is it. To assert that a forgery has been made is one thing; to identify it with a known object is quite another. No such identification has been made, and this story, like a number of others, fails to qualify as evidence. (Chickering, Farquhar, & Starr, 1953: 28)

I.e., ‘Even if there was a hoax plate, no one has done anything to prove that this plate is a hoax’. Oh, there’s no real good place to drop this titbit, but just so you know, Farquhar is also an ECV member (2002: 131).

Anyway. More interesting than his argument against the plate being a hoax is the fact that he’s heard this story. Who’s his source? It’s a Clamper called Lorenz Noll. In 1950 he’d told some other Clampers about the hoax, and the story was actually published in a Historical newsletter called the Pony Express, and in 1953 the same newsletter published another article with more details of the same story (2002: p.170, fn. 46, 48). Unfortunately I can’t find the newsletter online, so I couldn’t look at the articles themselves. Other sources from the same time also report Noll having told others about the hoax, but… none of those are available online either. Which is incredibly frustrating. So basically, there are multiple small sources reporting Noll’s story of the hoax, but I can’t read any of them.

Farquhar even mentions that another person has come forward claiming to have seen the plate even before Caldiera. One Mrs. Limback gave an interview to the Oakland Tribune in 1956 claiming she had seen the plate, nailed to a tree, with the sixpence still in it, way back in 1892. But that was nearly 60 years ago. Farquhar doesn’t doubt her sincerity, but the event she’s remembering happened over 60 years ago, and thus the reliability of the memory is highly questionable (Chickering, Farquhar, & Starr, 1957: 27-8). Which is true.

Now, as I said, for a lot of people, Fink and Polushkin’s 1939 analysis was the last word on the matter, despite the stories of ECV involvement. Which is not to say there was no continued questioning. Multiple scholars wrote to Bolton and his colleagues expressing their doubts based on various evidence and areas of expertise – from the modern spelling, the weird double-R ‘Herr’, the letterings used, the fact that there probably would have been a competent metalworker on board… literally every aspect of the plate is questioned. All the things Haselden pointed out as needing further investigation, people are talking about. One Professor, Earle Caley, even wrote in pointing out that the zinc content in the plate matches modern brass more closely than samples taken from other Elizabeth brass, and literally even describes how a forgery that would match the plate could be made (1977: 29-33). But… these were confidential letters, and discussions in person, not articles in journals, and they weren’t published. So anyone looking at the situation at the time would think there was greater consensus than there was.

It also makes it hard to tell what any individual scholar at the time would know. Had they talked to one of the sceptics, or heard about their objections? Or were they oblivious to them? Who knows. But there were certainly enough scholars convinced it was genuine that the Drake plate became an important piece of evidence in support of various theories of where Drake’s original landing site had been, who exactly Drake encountered, etc.

So if none of the objections and doubts was published, how do we know about them? Because in 1977 the Bancroft Library, owners of the Plate, released the findings of a new report into the plate. This new investigation had been triggered by the arrival of a new director, who was aware of the controversy still lingering around the plate, and who thought that, given the 400th anniversary of Drake’s landing was coming up, there would be renewed interest in the plate.

And y’all this report is something else. Apart from the revelation of the letters and discussions from all these sceptics over the years, making multiple very reasonable points that really should have made their way into publications, some of the results of the new examinations are just… What?

Remember that mineralized plant matter? That ‘always provides unquestionable proof of authenticity’, because that type of mineralization takes a super long time? Well. When they got someone from their department of Palaeontology to look at the photos Fink and Polushkin had taken, he said ‘yup, that looks like mineralized plant matter, but, uh, that can happen in just a few years’ (1977: 12). In itself that’s a death sentence for that pro-legit argument, but just for an added seasoning of absurdity, when they showed the pics to one of their Biology Professors, he believed it was just some wood that had got jammed (1977: 12). Oh, if you’re wondering why they’re only looking at the photos, it’s because it turns out they couldn’t find the original sample. Probably it was destroyed during the tests Fink and Polushkin conducted.

The Library had also had samples sent to two different labs, one in Oxford and the other at the University of California itself, and their findings confirm what Earle Caley had pointed out. The Zinc content is about what Fink and Polushkin said it was – 34%ish, but that matches up way more closely with new brass than old brass (1979: 17). And on top of that, the lead and tin levels also matched modern brass way more closely (1979: 18; 41; 50, 52-55). The Oxford lab mentions that it’s rare to find either lead or tin in such low levels in antique brass, and finding such low levels of both is even rarer (1977: 42).

Both labs actually bothered to test other old brass from the period, and found that it didn’t match the composition of the Drake Plate. One of the labs even pinpoints a modern sheet of brass, known as ‘alloy number 268, or 268 sheet brass’ which has the composition that matches the ranges in the Drake Plate. (1979: 19, 41-43).

Oh, and remember the magnesium? That was present at 0.01%, compared to 0.002% in modern brass? Y’know, the one thing that actually did seem more indicative of an older date?

One of the labs tested that and came out with a value one tenth that of Fink and Polushkin (1977: 18, 65). Sooo… 0.001%, not 0.01%. The one thing that suggested it was old… they got wrong. Golfclap for them.

So… however bad you thought Fink and Polushkin’s study was when we were going through it, it was actually worse. Because they were wrong about… how long plants take to mineralize and what the chemical composition of old and new brass was. Like… the things that were easiest to get right.

The Lawrence Berkley Laboratory also concluded that the plate was made of rolled brass and then hammered afterwards (1977: 22). Another guy from another lab also reached the same conclusion after performing an ultrasonic examination of the plate (1977: 22-23).

Someone else at yet another lab reports back that the corrosion of brass could happen quickly and could not be used as evidence of antique brass (1977: 23). In fact, he goes further than that and states that the corrosion present on the plate isn’t what you’d expect to find on brass that had been buried for centuries (1977: 70).

The Library also called in another guy who looked at the plate way more thoroughly under a microscope, and disagreed with Fink and Polushkin that it had been hammered rather than rolled. And he even correctly guessed that it was a guillotine shear that was used to cut the plate to size, and that the rough appearance of the edge of the plate had been made by someone hammering at it to disguise the tell-tale shear marks (1977: 21, 74).

The frustrating thing here… or. Well. One of the many frustrating things, here. Is that the labs associated with this new report have stronger evidence now for a modern date for the brass than Fink and Polushkin ever had for it being old. And yet, because these people are actually good at doing the objectivity thing, they treat the conclusions that can be drawn from their results with more caution. For instance, the guy who founded the lab at Oxford, which was specifically dedicated to archaeology and history of art, had been influential in debunking another historical hoax – the Piltdown man. And yet, he concluded that the results of the analysis were clear and consistent, but he didn’t think they could be used in isolation as proof beyond all doubt for establishing whether the plate is a hoax or if it’s legit (1977: 18). Pretty much all of them say ‘this particular evidence does not support an old date for the plate, but you can’t use it by itself, you need to take it in context with other evidence’. Because they’re actually good scientists, they won’t commit with the reckless certainty offered by Fink and Polushkin’s report. But obviously, the report isn’t just one researcher saying ‘well, I found this, but you’d need to support a conclusion with more evidence’. They have a bunch of evidence from a bunch of such researchers.

And yet, even the guy who was collating and summarising the reports, James Hart, pulls back from an outright condemnation. He concludes his summaries of the reports by noting that for some people, though ‘probably not all’ the results of the tests will settle the matter conclusively in favour of it being a hoax.

But he also notes that people have proffered explanations of who might have perpetrated the hoax - usually that it was one of Bolton’s students who knew of his obsession with the plate, because this kind of gag is totally typical of undergrad humour. But the plate’s defenders pointed out that usually the point of a hoax is to show up someone as a bit too gullible, and the fact that no one had come forward to claim the hoax indicated it was real. Which is a bad argument. As we all know, there are multiple reasons people perpetrate hoaxes. Sceptics had responded by suggesting that whoever made the plate had been too embarrassed to come forward when Bolton had committed himself to the authenticity (1977: 24).

Hart even very obliquely references the fact that some people have even suggested the names of some of the potential hoaxers, who all died a few years after the plate was discovered. He doesn’t name names, or give sources, but it’s not hard to guess that he’s talking about Barron, Dane, and Clark.

After the report and press statement, the newspapers ran the story that the plate was a hoax. This upset those who didn’t want to accept the plate was a hoax, because those damn newspapers were totally sensationalising and over-stating what the report said.

In 1978, the ECV issued a reprint of the The Preposterous Booke of Brass. Y’know, that one written by Lead Clamper Charles Camp in 1937, that literally told people to look for the ECV letters in translucent fluorescent paint on the back of the plate. If that suddenly made you wonder: No. No one involved in the 1977 report checked for that. In their defence, most of them wouldn’t have been aware of the Clamper book, so wouldn’t have cause to look.

In the introduction to the reprint, Carl Briggs, yet another Clamper, stated that he did not know who made the plate, but said that ‘Clampers have been hoaxing the suckers for a long, long time, and are masters of the game’.

Now, I know what you’re asking. Did anyone ever actually do this basic, non-invasive test to look for the letters???

And I’m pleased to inform you that the answer is yes. Yes they did.

It was tested in 1992, and 2002. They found small spots of luminescence firmly stuck to the indentations on the back of the plate. This luminescence is not natural to brass, and they ruled out that it could have come from either an artificial weathering process, or the soil because it was only found on the back of the plate. No specks of it at all on the front – not even in the letters, or the similar indentations on the front of the plate (2002: 168-69, fn. 13).

Unfortunately, these spots of luminescence only remained around the hole chiselled out for the coin, because not only had Mr. Shinn partly cleaned the plate when he found it, but later, a group of printers had cleaned the plate with kerosene when consulted about how to make reproductions of it (2002: 169, fn. 13).

In background: chirrup of a cat.

That little chirrup noise was one of my cats, and I refuse to remove it.

So how much damage did this hoax actually do? Well. Firstly, so much scholarship had been written and developed using the plate as evidence, which was now all… well. Pretty much useless. Any academic who’d dedicated significant chunks of their career writing articles that utilised the plate as evidence was suddenly faced (providing they hadn’t already died), with the fact that they had been wasting so much time and energy. I can’t imagine how much it must suck to discover that.

The plate had appeared on the cover of California School textbooks printed during the years it was thought to be legit. There are people alive today who were taught using those textbooks. I wonder if they all later heard the announcement that it was a hoax. Are there still people around who think it’s real? More on that in a minute.

Y’see, the problem with hoaxes is that… they never really die. Even if they’re detected immediately. For some people, nothing will ever convince them that a hoax is a hoax, no matter what the evidence. Lookin’ at you, Nessie.

When I was trying to find photos of the plate to share on twitter, I stumbled across a conspiracy about the plate. The article had been viewed 212 times. The theory makes no sense, but hey. That’s never really an issue for conspiracy theorists. Their claim is that for some inexplicable reason, some shadowy, unnamed “officials” at the Bancroft Library decided that the plate contained… a secret code. Of course, there’s literally no evidence for this, but hey. Supposedly the secret code would reveal the location of… drumroll… buried treasure!!

I have literally no idea why the Officials would need the real thing, rather than just being able to make a replica, or just write the inscription on it down. Was the code like… contained in the composition of the metal? The patina? Nobody knows. Because this makes no sense.

I’m not even going to go into the rest of their argument, because… it genuinely doesn’t deserve the time of day. Like, they literally claim that the plate of the text changed between the “real” plate and the forgery it was “replaced with”. These actual experts in the early European history of California who were super familiar with the actual plate and could actually look at it in person somehow fudged their copy attempt so badly as to get the text itself wrong. And yet, y’know. Also managed to reproduce the rest of it down to being literally identical to photos taken of the “real” plate. And they use some of the arguments made by those people who published the article arguing that it was still real in 1978.

The argument ends with a plea to help share this totally reasonable and true story, to (in capital letters) ‘HELP CORRECT WORLD HISTORY’. So for once, I’m not going to be including a source in the bibliography, because: no.

It took four historians 11 years to go through all the information and correspondence from the time to establish what was being said among Clampers: Edward Von der Porten, Raymond Aker, Robert Allen, and James Spitze. Their paper was published in 2002, and has been super helpful for writing this episode as the primary source for information about the Clamper involvement.

They’re a little more upbeat than me about the legacy of the plate. Possibly because they didn’t read the same conspiracy nonsense that I did. They point out that on the plus side, the plate enhanced interest in, and awareness of, early European California history, and the plate was the impetus for several archaeological digs that did turn up genuine historical artefacts (2002: 133).

Of course, being actually decent academics, Von der Porten and his colleagues don’t rule out the possibility that claiming ownership of the hoax is itself a hoax, but given that the Clampers have been indicating it was a hoax from the very beginning, and the details of the fluorescent paint, I think it’s pretty damn likely that they nailed it.

Today, the Drake Plate is on permanent exhibit at the Bancroft Library at the University of California, Berkley. You know what the final absurd thing is in this story? Despite the text on the website of the library being revised in 2015 - twelve years after after Von der Porten and company published their article, it makes no mention of who was behind the hoax. On the contrary, it actually states that questions about who made the plate remain ‘unanswered’. The same institution that literally published a press report about Von der Porten and co.’s findings… doesn’t mention their findings on their website about the plate. This bugged me so much that I actually emailed them about it. I haven’t heard back.

As for the real plate? Who knows. It’s never been found. I find it highly unlikely that it ever will be. All the likely sites for its initial location have since eroded into the sea. And if anyone ever does find another plate, the shadow of the Clamper plate is going to hang over it.

And that’s it for this week. I’m going to be taking the next two weeks off because there’s some vague small holiday thing going on, but I’ll be back on January the 9th.

Thanks for listening. If you like the show, please subscribe on whatever podcatcher you’re using. Rate and review the show, especially on iTunes. And if you happen to do the Christmas thing, and really like the show, there’s a link in the show notes to my Amazon wishlist for books to help research this podcast. If you do happen to want to get a book from the list, please, go for the cheapest readable secondhand copy. I love secondhand books.

Transcript link: Poison Room Podcast Amazon Wishlist.

If you have questions, comments, feedback, want to suggest a topic, etc. You can find the podcast on twitter @poisonroompod, or send an email to: poisonroompodcast@gmail.com

Alternatively, let me know that you painted a message in translucent, florescent paint on the back of some artifact, and I’ll get someone to check it out for me about forty years from now.

Transcripts of all episodes are available at poisonroom.com, where you can also see the references and bibliography. As always if the sources are publicly available, they’re linked to.

You have been listening to The Poison Room, a podcast that cannot be used to establish where Drake landed.


Bolton, H. E. (1937a) ‘Francis Drake’s Plate of Brass’ California Historical Society Quarterly Vol. 16: 1-16.

--- (1939) ‘Further Notes on the Drake Plate’ California Historical Society Quarterly Vol. 18: 251-53.

Chickering, A. L., Farquhar, F. P., & Starr, W. A. (1957) ‘Drake in California: A Review of the Evidence and the Testimony of the Plate of Brass’ California Historical Society Quarterly Vol. 36: 21-34.

Fink, C. G., Chickering, A. L., Polushkin, E. P., & Hildebrand, J. H. (1938) ‘The Report on the Plate of Brass’, California Historical Society Quarterly Vol. 17: 1-29.

Guerra, M. F. (2008) ‘Archaeometry and museums: fifty years of curiosity and wonder’ Archaeometry Vol. 50: 951-67.

Hart, J. D. (Ed.) (1977) The Plate of Brass Reexamined: a Report, Bancroft Library.

Power, R. H. & Pike, D. C. (1978) ‘A Plate of Brass “By Me… C. G. Francis Drake” California History Vol. 57: 172-185).

Von der Porton et al. (2002) ‘Who Made Drake’s Plate of Brass? Hint: It Wasn’t Francis Drake’ California History 81: 116, 133 (footnotes: 167-170).