Detection by Gaslight (19 page)

Rodney looked dissatisfied. “If,” said he, “the item of evidence that you refer to is the button, it seems to me that we have got all that we are likely to get out of it. We have identified it, and we know that it has been thrown up on the beach at Morte Hoe. What more can we learn from it?”

“That remains to be seen,” replied Thorndyke. “We may learn nothing, but, on the other hand, we may be able to trace the course of its travels and learn its recent history. It may give us a hint as to where to start a fresh inquiry.”

Rodney laughed sceptically. “You talk like a clairvoyant, as if you had the power to make this bit of cork break out into fluent discourse. Of course, you can look at the thing and speculate and guess, but surely the common sense of the matter is to ask a plain question of the man who probably knows. If it turns out that Varney saw Purcell throw the button overboard, or can tell us how it got into the sea, all your speculations will have been useless. I say, let us ask Varney first, and if he knows nothing, it will be time to start guessing.”

But Thorndyke was calmly obdurate. “We are not going to guess, Rodney; we are going to investigate. Let me have the button for a couple of days. If I learn nothing from it, I will return it to you, and you can then refresh your legal soul with verbal testimony. But give scientific methods a chance first.”

With evident reluctance Rodney handed him the little box. “I have asked your advice,” he said rather ungraciously, “so I suppose I must take it; but your methods appeal more to the sporting than the business instincts.”

“We shall see,” said Thorndyke, rising with a satisfied air. “But, meanwhile, I stipulate that you make no communication to anybody.”

“Very well,” said Rodney; and we took leave of the two brothers.

“As walked down Chancery Lane, I looked at Thorndyke, and detected in him an air of purpose for which I could not quite account. Clearly, he had something in view.

“It seems to me,” I said tentatively, “that there was something in what Rodney said. Why shouldn't the button just have been thrown overboard?”

He stopped and looked at me with humorous reproach. “Jervis!” he exclaimed, “I am ashamed of you. You are as bad as Rodney. You have utterly lost sight of the main fact, which is a most impressive one. Here is a cork button. Now an ordinary cork, if immersed long enough, will soak up water until it is water-logged, and then sink to the bottom. But this one is impregnated with paraffin wax. It can't get water-logged, and it can't sink. It would float for ever.”

“Well?”

“But it
has
sunk. It has been lying at the bottom of the sea for months, long enough for a
Terebella
to build a tube on it. And we have D'Arcy's statement that it has been lying in not less than ten fathoms of water. Then, at last, it has broken loose and risen to the surface and drifted ashore. Now, I ask you, what has held it down at the bottom of the sea? Of course, it may have been only the coat, weighted by something in the pocket; but there is a much more probable suggestion.”

“Yes, I see,” said I.

“I suspect you don't—altogether,” he rejoined, with a malicious smile. And in the end it turned out that he was right.

The air of purpose that I noted was not deceptive. No sooner had we reached our chambers, then he fell to work as if with a definite object. Standing by the window, he scrutinised the button, first with the naked eye, and then with a lens, and finally laying it on the stage of the microscope, examined the worm-tube by the light of a condenser with a two-inch objective. And the result seemed to please him amazingly.

His next proceeding was to detach, with a fine pair of forceps, the largest of the tiny fragments of stone of which the worm-tube was built. This fragment he cemented on a slide with Canada balsam; and, fetching form the laboratory a slip of Turkey stone, he proceeded to grind the little fragment to a flat surface. Then he melted the balsam, turned the fragment over, and repeated the grinding process until the little fragment was ground down to a thin film or plate, when he applied fresh balsam and a cover-glass. The specimen was now ready for examination; and it was at this point that I suddenly remembered I had an appointment at six o'clock.

It had struck half-past seven when I returned, and a glance round the room told me that the battle was over—and won. The table was littered with trays of mineralogical sections and open books of reference relating to geology and petrology, and one end was occupied by an outspread geological chart of the British Isles. Thorndyke sat in his armchair, smiling with a bland contentment, and smoking a Trichinopoly cheroot.

“Well,” I said cheerfully, “what's the news?”

“He removed the cheroot, blew out a cloud of smoke, and replied in a single word:

“Phonolite.”

“Thank you,” I said. “Brevity is the soul of wit. But would you mind amplifying the joke to the dimensions of intelligibility?”

“Certainly,” he replied gravely. “I will endeavour to temper the wind to the shorn lamb. You noticed, I suppose, that the fragments of rock of which that worm-tube was built are all alike?”

“All the same kind of rock? No, I did not.”

“Well, they are, and I have spent a strenuous hour identifying that rock. It is the peculiar, resonant, volcanic rock known as phonolite or clink-stone.”

“That is very interesting,” said I. “And now I see the object of your researches. You hope to get a hint as to the locality where the button has been lying.”

“I hoped, as you say, to get a hint, but I have succeeded beyond my expectations. I have been able to fix the locality exactly.”

“Have you really?” I exclaimed. “How on earth did you manage that?”

“By a very singular chance,” he replied. “It happens that phonolite occurs in two places only in the neighbourhood of the British Isles. One is inland and may be disregarded. The other is the Wolf Rock.”

“The rock of which Philip Rodney was speaking?”

“Yes. He said, you remember, that he was afraid that the yacht might drift down on it in the fog. Well, this Wolf Rock is a very remarkable structure. It is what is called a ‘volcanic neck,' that is, it is a mass of altered lava that once filled the funnel of a volcano. The volcano has disappeared, but this cast of the funnel remains standing up from the bottom of the sea like a great column. It is a single mass of phonolite, and thus entirely different in composition from the seabed around or anywhere near these islands. But, of course, immediately at its base, the sea-bottom must be covered with decomposed fragments which have fallen from its sides, and it is from these fragments that our
Terebella
has built its tube. So, you see, we can fix the exact locality in which that button has been lying all the months that the tube was building, and we now have a point of departure for fresh investigations.”

“But,” I said, “this is a very significant discovery, Thorndyke. Shall you tell Rodney?”

“Certainly I shall. But there are one or two questions that I shall ask him first. I have sent him a note inviting him to drop in to-night with his brother, so we had better run round to the club and get some dinner. I said nine o'clock.”

It was a quarter to nine when we had finished dinner, and ten minutes later we were back in our chambers. Thorndyke made up the fire, placed the chairs hospitably round the hearth, and laid on the table the notes that he had taken at the late interview. Then the Treasury clock struck nine, and within less than a minute our two guests arrived.

“I should apologise,” said Thorndyke, as we shook hands, “for my rather peremptory message, but I thought it best to waste no time.”

“You certainly have wasted no time,” said Rodney, “if you have already extracted its history from the button. Do you keep a tame medium on the premises, or are you a clairvoyant yourself?”

“There is our medium,” replied Thorndyke, indicating the microscope standing on a side-table under its bell glass. “The man who uses it becomes to some extent a clairvoyant. But I should like to ask you one or two questions if I may.”

Rodney made no secret of his disappointment. “We had hoped,” said he, “to hear answers rather than questions. However, as you please.”

“Then,” said Thorndyke, quite unmoved by Rodney's manner, “I will proceed; and I will begin with the yacht in which Purcell and Varney travelled from Sennen to Penzance. I understand that the yacht belongs to you and was lent by you to these two men?”

Rodney nodded, and Thorndyke then asked: “Has the yacht ever been out of your custody on any other occasion?”

“No,” replied Rodney, “excepting on this occasion, one or both of us have always been on board.”

Thorndyke made a note of the answer and proceeded: “When you resumed possession of the yacht, did you find her in all respects as you had left her?”

“My dear sir,” Rodney exclaimed impatiently, “may I remind you that we are inquiring—if we are inquiring about anything—into the disappearance of a man who was seen to go ashore from this yacht and who certainly never came on board again? The yacht is out of it altogether.”

“Nevertheless,” said Thorndyke, “I should be glad if you would answer my question.”

“Oh, very well,” Rodney replied irritably. “Then we found her substantially as we had left her.”

“Meaning by ‘substantially'?——”

“Well, they had had to rig a new jib halyard. The old one had parted.”

“Did you find the old one on board?”

“Yes; in two pieces, of course.”

“Was the whole of it there?”

“I suppose so. We never measured the pieces. But really, sir, these questions seem extraordinarily irrelevant.”

“They are not,” said Thorndyke. “You will see that presently. I want to know if you missed any rope, cordage, or chain.”

Here Philip interposed. “There was some spun-yarn missing. They opened a new ball and used up several yards. I meant to ask Varney what they used it for.”

Thorndyke jotted down a note and asked: “Was there any of the ironwork missing? Any anchor, chain, or any other heavy object?”

Rodney shook his head impatiently, but again Philip broke in.

“You are forgetting the ballast-weight, Jack. You see,” he continued, addressing Thorndyke, “the yacht is ballasted with half-hundredweights, and, when we came to take out the ballast to lay her up for the winter, we found one of the weights missing. I have no idea when it disappeared, but there was certainly one short, and neither of us had taken it out.”

“Can you,” asked Thorndyke, “fix any date on which all the ballast-weights were in place?”

“Yes, I think I can. A few days before Purcell went to Penzance we beached the yacht—she is only a little boat—to give her a scrape. Of course, we had to take out the ballast, and when we launched her again I helped to put it back. I am certain all the weights were there then.”

Here Jack Rodney, who had been listening with ill-concealed impatience, remarked:

“This is all very interesting, sir, but I cannot conceive what bearing it has on the movements of Purcell after he left the yacht.”

“It has a most direct and important bearing,” said Thorndyke. “Perhaps I had better explain before we go any further. Let me begin by pointing out that this button has been lying for many months at the bottom of the sea at a depth of not less than ten fathoms. That is proved by the worm-tube which has been built on it. Now, as this button is a waterproofed cork, it could not have sunk by itself; it has been sunk by some body to which it was attached, and there is evidence that that body was a very heavy one.”

“What evidence is there of that?” asked Rodney.

“There is the fact that it has been lying continuously in one place. A body of moderate weight, as you know, moves about the sea-bottom impelled by currents and tide-streams, but this button has been lying unmoved in one place.”

“Indeed,” said Rodney with manifest scepticism. “Perhaps you can point out the spot where it has been lying.”

“I can,” Thorndyke replied. “That button, Mr. Rodney, has been lying all these months at the base of the Wolf Rock.”

The two brothers started very perceptibly. They stared at Thorndyke, they looked at one another, and then the lawyer challenged the statement.

“You make this assertion very confidently,” he said. “Can you give us any evidence to support it?”

Thorndyke's reply was to produce the button, the section, the test-specimens, the microscope, and the geological chart. In great detail, and with his incomparable lucidity, he assembled the facts, and explained their connection, evolving the unavoidable conclusion.

The different effect of the demonstration on the two men interested me greatly. To the lawyer, accustomed to dealing with verbal and documentary evidence, it manifestly appeared as a far-fetched, rather fantastic argument, ingenious, amusing, and entirely unconvincing. On Philip, the doctor, it made a profound impression. Accustomed to acting on inferences from facts of his own observing, he gave full weight to each item of evidence, and I could see that his mind was already stretching out to the, as yet unstated, corollaries.

The lawyer was the first to speak. “What inference,” he asked, “do you wish us to draw from this very ingenious theory of yours?”

“The inference,” Thorndyke replied impassively, “I leave to you; but perhaps it would help you if I recapitulate the facts.”

“Perhaps it would,” said Rodney.

“Then,” said Thorndyke, “I will take them in order. This is the case of a man who was seen to start on a voyage for a given destination in company with one other person. His start out to sea was witnessed by a number of persons. From that moment he was never seen again by any person excepting his one companion. He is said to have reached his destination, but his arrival there rests upon the unsupported verbal testimony of one person, the said companion. Thereafter he vanished utterly, and since then has made no sign of being alive, although there are several persons with whom he could have safely communicated.