“No,” agreed Thorndyke, rising and knocking out his pipe. “And now I must be going. Do you care to walk with me to the bottom of Doughty-street, Gray?”
I assented at once, suspecting that he had something to say to me that he did not wish to say before Cornish. And so it turned out; for as soon as we were outside he said:
“What I really called about was this: it seems that we have done the police an injustice. They were more on the spot than we gave them credit for. I have learned—and this is in the strictest confidence—that they took that coin round to the British Museum for the expert’s report. Then a very curious fact came to light. That coin is not the original which was stolen. It is an electrotype in gold, made in two halves very neatly soldered together and carefully worked on the milled edge to hide the join. That is extremely important in several respects. In the first place, it suggests an explanation of the otherwise incredible circumstance that it was being carried loose in the waistcoat pocket. It had probably been recently obtained from the electrotyper. That suggests the question, is it possible that D’Arblay might have been that electrotyper? Did he ever work the electrotype process? We must ascertain whether he did.”
“There is no need,” said I. “It is known to me as a fact that he did. The little plaquettes that I took for castings are electrotypes, made by himself. He worked the process quite a lot, and was very skilful in finishing. For instance, he did a small bust of his daughter in two parts and brazed them together.”
“Then, you see, Gray,” said Thorndyke, “that advances us considerably. We now have a plausible suggestion as to the motive and a new field of investigation. Let us suppose that this man employed D’Arblay to make electrotype copies of certain unique objects with the intention of disposing of them to collectors. The originals, being stolen property, would be almost impossible to dispose of with safety, but a copy would not necessarily incriminate the owner. But when D’Arblay had made the copies, he would be a dangerous person, for he would know who had the originals. Here, to a man whom we know to be a callous murderer, would be a sufficient reason for making away with D’Arblay.”
“But do you think that D’Arblay would have undertaken such a decidedly fishy job? It seems hardly like him.”
“Why not?” demanded Thorndyke. “There was nothing suspicious about the transaction. The man who wanted the copies was the owner of the originals, and D’Arblay would not know or suspect that they were stolen.”
“That is true,” I admitted. “But you were speaking of a new field of investigation.”
“Yes. If a number of copies of different objects have been made, there is a fair chance that some of them have been disposed of. If they have, and can be traced, they will give us a start along a new line, which may bring us in sight of the man himself. Do you ever see Miss D’Arblay now?”
“Oh, yes,” I replied. “I am quite one of the family at Highgate. I have been there every Sunday lately.”