Holmes having made his final inspections, we returned to Lestrade's office. His batman brought us coffee as we discussed the matter.
"I agree, it is certainly worthy of some investigation, if the Yard can rely on your support, Mr Holmes. I have precious few officers available at the best of times, but as you have seen from the condition of our mortuary we are rather busy at the moment," said Lestrade.
Holmes was pleased; Lestrade had effectively given him free reign, and he could count on police support should we need it.
"You will delay the interment of the bodies for now?"
"You are in luck; we have something of a backlog to clear. However I cannot detain them indefinitely. These things have a tendency to spoilage."
Holmes seemed satisfied with that. "Thank you, Lestrade, and good day."
We caught a Hansom on Northumberland Avenue and headed for Baker Street. Holmes did not speak to me until we had almost reached Marylebone.
"This is quite the problem, Watson."
His voice was grave and his expression stern.
On reaching our rooms, Holmes began to trawl through his cases of documents. It seemed that he was in pursuit of maps of the city either side of the Pool of London, and rolled them out on the floor in his bedroom. I took tea while he crawled over them and circled them like a great bird of prey. He wandered in and out with pieces of scientific glassware. I knew better than to interfere. I contemplated what I knew of the situation, which I realised was little. We sought a sailor who kept the company of young boys, engaged in work about the river, who dealt harsh discipline. We knew not any malicious intent, only that the children had died in similar circumstances. As was so often the case, we were looking for one man in a city of five million. Sailors were far from uncommon in a port city. I could deduce no more about where or how we might find him from the information I had, but Holmes clearly had other thoughts. I knew that he would share them with me when he was ready. However, my thoughts shifted toward what we had done before in a situation where we were seeking a particular individual from the masses; we would call in the Baker Street Irregulars. I realised that doing this would be difficult for Holmes.
Though difficult to concentrate on it, I busied myself with writing up some of my stories of our previous adventures together. I had some lingering help that reference to the past might help me shed some light on this particular case. It did not, however, and it was early evening before Holmes rolled up his maps, lit a pipe, and sat down smoking most furiously in the chair opposite, cross-legged. I waited to be addressed.
"What do you know of density, Watson?"
"Density?" I am of course, quite aware of the scientific principle, but what this had to do with the situation was beyond me.
"Specifically, the density of the human body."
"I don't know, Holmes."
"Hmmm." He puffed on his pipe.
"I suppose on average it should be about the same as that of water; a man will only just float or only just sink in water."
"As I supposed," said Holmes. "What about a frozen body?"
I could now almost follow his reasoning. "A frozen body should have a lower density."
"And thus a greater buoyancy."
"Indeed."
"Then it strikes me as a little odd that these bodies were all found so close together. Even if we suppose that all of them entered the water at the same point, the currents of the river should scatter them about some distance. You said also that it was difficult to be specific about a time of death."
"Yes. A body kept very cold will be much better preserved than an ambient one. The signs of how long a body has been dead are much more difficult to read."
"So the bodies could be farther spaced out in time of death than of discovery."
"Absolutely."
He pondered for some minutes with his fingers gripping his pipe.
"Have you any more on our sailor?" I asked.
"Only that he is an older man."
"Why do you say that?"
"He is clearly an accomplished sailmaker, a skill which is not very common in the most recent generation of seaman."
This was certainly true.
"How are we to find him?"
"I am sure that we will find him close to the river, between Blackfriars and Limehouse, on one or other side of the river."
My heart sank. That was a colossal area to search. Limehouse particularly was noted for the large numbers of sailors who resided there. Holmes continued.
"I have made some study of the patterns of currents of the river. Our bodies could not naturally have come from further up the river and have been found where they were. I have also examined some of the mud found on the most recent boy. The mud further downriver than Limehouses and Rotherhithe is quite different. This is city mud of the finest quality."
It was a difficult task but Holmes had managed to shrink a search among five million to perhaps tens of thousands. "How do we find him?" I interjected. "I can hardly imagine that Lestrade's offer of police support extends to Constables questioning every sailor along the riverbank."
"Quite," said Holmes, wryly.
"The Irregulars?" I asked.
"Indeed," said Holmes, more easily than I thought he would.
