'Precisely,' declared Holmes, 'and thereby our case is closed. I am deeply grateful to you, Mr Swain.'
The confused photographer took the money that Holmes offered, thanked him and left rapidly, as though he feared my friend would change his mind.
When the coffee was done Holmes drew out his watch. 'We might', he said, 'catch the mid-afternoon express to London. Would you be so kind as to ask the boy for our bags and the reckoning?'
On the way back to London Holmes discoursed wittily on anarchists and poisoners, on underworld argot and a dozen different topics, but I heard him with only half an ear for my mind was churning in its attempts to make sense of what Sherlock Holmes evidently regarded as a successful enquiry. At length I could stand it no longer.
'Holmes!' I exclaimed, 'I have never been so completely at a loss to understand one of your enquiries. What in Heaven's name has this all been about?'
He laughed. 'Do you recall', he said, 'that when we had not known each other long you took issue with me over my
proposition that, by logical deduction, it should be possible to infer the existence of an ocean from a single grain of sand?' 'Well, yes,' I said, 'but I was not then so familiar with your remarkable methods.'
'I fear,' he said, 'that you are not yet familiar with them. I have been engaged in one of the most enjoyable enquiries that I
can recall, enjoyable because I have had to infer the existence of something which I have never seen and to construct the pattern of its movements and assess its influence by pure reason.'
'You have left me a long way behind,' I grumbled.
'Consider the patterns, Watson,' he said.
'The patterns on the casket?' I asked. 'What of them?' 'No, Watson,' he sighed. 'The patterns of the evidence as it unfolded.' He leaned forward.
'Let us begin at the beginning. The newspapers told us that snow would not lie and grass would not grow upon the Black
Barrow. I admit I took that for folklore or exaggeration, but you heard Edgar say that it was the case. What did that suggest to you?'
I confessed to no idea at all.
'Watson!' he expostulated. 'You have been in mining districts; you have seen heaps of coal waste on which grass will not grow nor the snow lie.'
'But that is caused by fires smouldering within the heaps,' I said. 'Ordinary soil does not smoulder, Holmes.'
'No indeed, Watson, but that analogy led me to believe that something within the barrow might be emitting some influence or emanation that warmed its surface yet discouraged growth.'
'Such as what?' I asked.
'I admit that, at first, I could see no solution along that line, but then I recalled pitchblende.'
'Pitchblende?' I echoed. 'What on earth is that?'
'It is an ore, of uranium, found in several places. For centuries German miners have been aware of it and afraid of it, for they
knew that it could cause burns and sickness. Now, you will recall my telling you of my experiments in coal-tar derivatives at the Montpelier laboratories in France, earlier this year?'
'Certainly.'
'Among my colleagues there was a French scientist, Jacques Curie, a specialist in electro-magnetism. He introduced me to a remarkable group of people who have theories about that substance. One was a Monsieur Bacquerel, another was Curie's own brother, Pierre, and another was Pierre's assistant and fiancee, a determined and intelligent young Polish lady called Marie Sklodovska. All of them believe that pitchblende emits some influence that can affect its surroundings.'
'Good Heavens!' I said. 'This sounds more like witch-craft than science.'
'I assure you that they are all very fine scientists, Watson, and it occurred to me to proceed on the basis that they are right and that pitchblende, or something like it, had been hidden in that barrow when it was first set up.'
He paused. 'That would neatly explain our first few facts, but what of the disease? Well, Mr Edgar gave us the answer to that, with his clear proof that the bronze casket had been rifled in the night. Edgar's spoiled photographs were also the proof that something was in the barrow that spoiled his plates. He failed to realise it, but the later success of his photography was also the proof that something had been removed from the mound. He was sadly wrong about Sir Andrew's guilt. It was, of course, the younger Lewis. No doubt, as Edgar described, he waited at the inn for his father's return, and Sir Andrew, fresh from his discovery, would certainly have mentioned it to his son. And so Anthony Lewis robbed the Black Barrow that night as a revenge on his father for refusing to meet his debts, and by so doing he brought about his own death.'
'By Jove!' I said, 'I begin to see. Everyone who came near was affected in some degree, but he slept with it beneath his bed,' and I shuddered at the thought of the luckless youth asleep while the malign emanations that Holmes had described seeped into him hour by hour.
'Exactly, Watson. I told you that we had stumbled upon a crime in our enquiries, but it brought with it its own fearful sentence. Sadly, the presence of that baleful urn at the 'Goat and Boots' was also responsible for the deaths and other effects in the village, though I suppose we should rejoice at the good fortune of Mrs Henty and young Mary. Evidently the influence of the substance is not entirely malign and, if my friends on the Continent, can refine and control it, it may yet prove a blessing.'
'If it can destroy a malignant tumour it will be an enormous blessing,' I said. 'But how came Sir Andrew to die of its effects and why does the snow still not lie on the Black Barrow? Is there more of the stuff still in there?'
Holmes shook his head. 'Sir Andrew would have realized his son's crime when he saw what was in the dead man's trunk, and to spare his dead son further shame he hid the urn. Somewhere secure, apparently, for it took ten years for the influence to affect him. When it did he will have realized the significance of the unique decoration on the outer casket. It was a warning that nobody heeded. He could not leave that deadly urn to destroy others. His notes prove that he connected it with his son's death and also suggested to me the remedy that he devised. The bolster confirmed it.'
'Bolster?' I said, 'Where was there a bolster?'
'A wooden implement, Watson, known as a bolster or lead-dresser, used by plumbers for knocking sheet lead into shape, as a moleskin pad impregnated with tallow is used to wipe the joints of leaden pipes and containers. Sir Andrew evidently recalled the leaden lining of the bronze casket and reasoned, perhaps, that it had some inhibiting influence on the ore's emanations. This morning's visit and Mr Swain's photographs confirmed my deduction. Sir Andrew's last visit to Addleton may have been to stand at his son's grave, but it was also to return the stolen urn to the Black Barrow. He was quite right. No one will re-open that mound, the locals keep away and there will never be a road or railway or houses on the Moor. Its poisonous influence is as harmless there as if it was at the bottom of the ocean.'
'I admit that it all makes sense,' I said, 'but it still seems very theoretical to me.'
'Theoretical!' he snorted. 'The pieces of my puzzle have been the words of witnesses who had no cause to lie. All I have added is the unproven, but entirely reasonable, theory of a number of eminent scientists. In the absence of data, Watson, it is permissible to theorize in directions which do not conflict with such data as does exist. It seems that my application of their theory has provided Curie and his friends with further data. In connection with which, Watson, I must ask you not to add this case to your published stories if only because publication might prematurely disclose the reasoning of my French friends and rob them of their just triumph in due course. But I must really write and tell Curie this singular tale.'
I confess that I had no intention of publishing an account of the Addleton affair. I could not fault Holmes's reasoning, but I could not quell a suspicion that it was all rather too logical and was not capable of proof.
Holmes wrote to Lady Cynthia and to Dr Leary, assuring them that the Addleton disease would never occur again and also to Edgar, explaining his understandable error. That fair-minded man wrote at once to the papers saying that, in the light of new information, he wholeheartedly and entirely withdrew any implication he had made against Sir Andrew Lewis.
Twenty-five years have elapsed since the Addleton tragedy and science has moved on. I owe my friend an
