Primo Levy said that 'lead is the metal of death'. You can't read about the Franklin Expedition for very long without coming across lead. Why?
The Franklin Expedition is unique in modern(ish) British exploration history in that it was the only such Expedition to disappear totally. Two apparently-well equipped Royal Navy exploration vessels, HMS Erebus and HMS Terror, set out in 1845 with combined crews of 134, including their commander Sir John Franklin, to attempt to sail through the North West Passage. Five men were sent back from Greenland, after which the two ships and the 129 men remaining on them completely disappeared. Over the 160 plus years since then, quite a lot has been found out about what happened to them. The bodies of three members of the Expedition have been autopsied and some human remains have been found, accounting for about 20% of the men altogether. But the ships have still not been found and much remains mysterious.
It is the total loss of the entire Franklin Expedition, with so many people, that is so anomalous. After all, Scott's last expedition is rightly seen as a tragedy, yet most of the people on the Expedition came back safely - only the five members of the Polar party actually died.
Ever since it became clear that the Expedition was a total loss, people have been trying to find a unique explanation for this apparently unique event. The tinned food which the Expedition took with it was an early candidate for suspicion. The contractor who supplied it definitely supplied the Royal Navy with substandard tinned meat later, and he was an early scapegoat for blame by the authorities in 1850's Britain. In fact the substandard meat he produced was supplied five years after the Franklin Evidence sailed. There is no evidence that the tinned food he supplied the Franklin Expedition was in any way tainted and there's quite a lot of anecdotal evidence that there was nothing wrong with it.
In the last thirty years two new theories have been advanced to try to provide an explanation for the Franklin Expedition disaster which relate to this tinned food. The first is the theory advanced by Scott Cookman in his best-selling book 'Ice Blink' that the provisions were tainted with botulism, which would have progressively and randomly killed off many of the Expedition, crippling it and making their deaths in the Arctic inevitable. The problem with this theory is that tinned food, while not sold in the shops in 1845, was certainly in quite common use on expeditions and long voyages. For example, Colonel Chesney took tinned food on the Euphrates Expedition of 1835-1837, on which James Fitzjames served. Ross and Crozier took tinned food on the Erebus and the Terror, when they sailed to the Antarctic in 1839-1843. So if botulism was such a killer in tinned food, we should expect to find some evidence of it on other expeditions. But we don't.
The second theory related to the tin cans is the lead theory advanced by Owen Beattie and John Geiger and popularised in their book "Frozen in Time". This is based on some epic original research by Owen Beattie. He actually autopsied the bodies of the three Expedition members who died during the winter of 1845-1846 while the Erebus and the Terror were locked in to Beechey Island by the ice. The descriptions of how his team and he carried out this tremendous work is gripping, and everybody owes them a huge debt of thanks for this work. Their most remarkable finding was that all three men had very high levels of lead in their bones and in their soft tissues. It is difficult to come up with an explanation for this, other than that all three men had had a recent and sustained exposure to lead. Given that they had been on the ships for up to nine months, that means the source of this lead must have been on the ships. This very significant finding has been corroborated by analysis of the bone fragments of some Expedition survivors who died on King William Island several years later - certainly not before 1848. Their bones all show evidence of a similar sustained exposure to lead. Together, these individuals account for something like 20% of the entire Expedition, and definitely do not all come from one of the ships (two of the Beechey Island dead were from the Erebus and one from the Terror). So it looks like the men on both ships were exposed to dangerous levels of lead while on the Expedition.
At first sight, the idea that the lead came from the tins looks compelling. You can see lead solder on the remains of tins from the expedition today. It was only when I studied what Dr. K.T.H. Farrer had written about it that I began to have doubts about this theory. If you read his research, notably his paper "Lead and the Last Franklin Expedition" published in the Journal of Archaeological Science, Vol. 20, No. 4. (July 1993), pp. 399-409, you can see that it does not appear to be possible for the men to have absorbed anything like the amount of lead seen by Owen Beattie, from the amount of tinned food they took on the expedition. So if it was the tinned food 'wot did it', both could not be correct: either the measurements of the lead in the bodies were wrong, or Dr. Farrer's findings were wrong. Yet they both seemd to make sense to me.
I read both men's research very carefully and puzzled over this for a long time. I decided I'd try to find out if there might be another, and much greater, source of lead on the ships which nobody else had thought of. I felt that whatever this source was, it had to be unique not just to these ships, but to these ships on this Expedition. Don't forget, the Erebus and the Terror only returned in 1843 from nearly four years exploring in the Antarctic. They took tinned food on that Expedition too, so on this basis tinned food fails the 'unique' test, as well as not containing enough lead. If the contemporary tinned food was so lethal, then surely we should hear of lead poisoning on the 1839-1843 Expedition? And we don't.
What I found is summarised in the paper I wrote: 'Identification of the Probable Source of the Lead Poisoning Observed in Members of the Franklin Expedition', which the Hakluyt Society kindly published in the online Journal of the Hakluyt Society in September 2008. I found that there was a pervasive source of potential lead on the Erebus and the Terror which was unique for this Expedition only. This 'uniqueness' means that for the first time we can fully accept the pathological evidence which Dr. Beattie presented in 'Frozen in Time' without needing to blame the tinned food. And what was this source? Well, I'd direct you to the paper so you can follow my argument and make up your own mind on what you think of the different probabilities.
Don't forget, there is no proof in all of this. Until someone finds the ships and tests their systems, it's all a question of probabilities based on the various pieces of research carried out so far.