concave mirror.”
He answered no more questions but instructed Tresawna to row toward the third rock that he had indicated.
This pinnacle had a natural sea pool at the foot of it, making an excellent landing place, and we could all climb out and follow a little circular path that went around the islandlike rock to a small cave. It was no higher than four feet at its entrance.
Holmes gave a cry of elation as he beheld it. He immediately bent down and entered. There was only room for himself in the cave, but we heard, almost at once, a further cry of exaltation. He reemerged pushing a large square glass container with some metal pieces in it, zinc and some other substance. This seemed to have been discarded at the back of the cave. Holmes brought it forward. There was a chemical smell to it which I hazarded was ammonium chloride.
“What do you make of that?” he announced.
Captain Trevossow and I exchanged a bewildered glance and shrugged.
Holmes sighed impatiently. “This is a Leclanche cell, and a pretty strong one,” he said irritably when he saw we were lost.
“An electric battery?” Captain Trevossow frowned. “What’s that doing on this godforsaken rock?”
Holmes gave him one of his enigmatic looks. “I am sure that we will be able to find the answer very soon.”
He suddenly took his magnifying glass from his pocket and examined a flattopped rock that was in the center of the entrance. He went down on his hands and knees and seemed to take a sighting from the rock, gazing straight out across the sea to the smaller pinnacle on which he had found the mirror fragments.
“You’ll notice the grooves here and the scraping of metal on this rock,” he inquired of us.
We both nodded, still confused.
Holmes stood up with a smile of satisfaction. “Excellent. I think that we will now pay a visit on Mr. Harry Penwarne at Tregriffian House.”
It took some time to row back to the shore and collect Sir Jelbart from Chy Trevescan. Leaving Noall Tresawna to attend to his boat, Sir Jelbart and his brother, Holmes and myself, climbed into the carriage and made the journey through Sennen along the road above Whitesand Bay to Tregriffian House.
Harry Penwarne was no more than thirtyfive. A young man whose boyish looks seemed to have a hardness to them. He smiled only with a movement of his facial muscles, but he bade us welcome to his house. I thought his eyes held a suspicious look in them. Then I realized that they were quite bloodshot. His manservant was a muscular man also with dour looks, who appeared less like a servant and more like a soldier or sailor. He spoke little, but I detected a French accent when he did.
“What can I do for you, Sir Jelbart?” he inquired. “What brings you and your friends to my house?”
Holmes intervened immediately. “You’ll forgive me,” he said, “but when I saw your diving experiments the other day, I just had to come and meet you.”
Penwarne’s eyes narrowed. He glanced at Sir Jelbart, who was looking in astonishment at Holmes.
“I didn’t know it was generally known that I was making such experiments.”
Holmes smiled. “My dear sir, I have been reading Kleingert of Breslau’s experimentations with diving equipment, and it seemed obvious you were using a machine to send compressed air to the diver.”
Harry Penwarne frowned. “Are you involved in deepsea diving, Mr. Holmes?”
“I have a little knowledge,” confessed Holmes. “Though I confess to being a mere amateur. I know that there are some new French inventions which have extended the time divers can remain underwater.”
“You mean the new compressor modification by Laplace of the Sorbonne?” inquired Penwarne.
“Exactly so. I understand that you, also, were a student at the Sorbonne?”
“I graduated from there ten years ago.”
“Pray what were you studying?”
“Marine engineering, of course.”
“I think, at that time, Dr. Marey was experimenting at the Sorbonne with his new invention, wasn’t he?”
“Dr. Marey? I do not know the gentleman.” Penwarne shook his head. “I am not a medical man, Mr. Holmes.”
Holmes looked at him sharply. “I did not say that he was a doctor of medicine.”
Penwarne’s mouth tightened.
“However, you are right. He was a physician, but his experiments were concerned with another discipline. Ten years ago, he invented the first motion pictures using a single camera.”
“Is that supposed to be of interest to me?” asked Penwarne defensively. “My study is marine engineering, sir.”
“You are possessed of a bright mind, Mr. Penwarne. You saw the potential of Marey’s camera and started your own development of it. But two years ago, Auguste and Louis Lumiere patented their cinematograph in Paris. They produced a combined camera and projector operating at sixteen frames a second. You were devastated. You were working on a similar system, but they were first with the patent. Therefore, I believe that you have turned your invention to a more dreadful use.”
“I have no idea what you mean,” protested Penwarne. His face was white now. His nervousness was selfevident. For the first time, I began to see the direction in which Holmes was leading.
“Your father was impecunious. You needed desperately to restore the family fortune; otherwise, you were faced with selling Tregriffian House to pay his debts. So a new plan came to your mind, one that would make you a mass murderer but rich. Using your projector, and a piece of film, you lured three ships to their doom. You went into the wrecking business as many folks in these parts used to do over a hundred years ago.”
“How do you claim that I managed to lure them?”
“With a film of some dancer that you probably made in Paris. Because of the angles involved to ensure the ships saw the image, you had to reflect your image via a third means. A concave mirror would bounce the image, which your projector shone onto it, across to the large rock covered with guano. That almost whitewash substance made a suitable screen on which to project it.”
“Rubbish,” snorted the now trembling Harry Penwarne. “The ships went down off the rocks. If I were able to do such a thing, how could I have collected the salvage from those wrecks?”
“You went diving there at night, with your assistant. People heard the whining and gasping of your compressed air apparatus, but being anchored behind the rocks, they did not see your boat. I presume that you went down looking only for the ship’s safe and taking cash and jewels. Perhaps you planned to lift some of the less easily negotiable materials at a later day….”
Harry Penwarne half rose from his chair, but his pale face and dark staring eyes were not on Holmes. They were staring past him.
“JeanClaude!” he cried in French. “We can bluff it out. Don’t give the game away!..”
I turned at once and saw Penwarne’s manservant leveling a revolver at Holmes.
I confess that I was considered something of a crack shot when I was serving in the Northumberland Fusiliers, but until that instant I had never shot so well. I did so from my lap, for thus far only could I draw my revolver and let off a shot that impacted on the hand of JeanClaude. He cried out in pain. The gun fell from his hand. Captain Trevossow leaped forward and scooped it up to cover the manservant.
I was now covering Harry Penwarne, but the shock of the discovery of his nefarious crimes sent the young man into a state of incapability. He collapsed back in his chair.
“I cannot believe it!” cried the astounded Sir Jelbart. “What made you suspect young Harry?”
“When I realized that he was using a compressed air machine on his boat, as I said. Also, when you told me about noticing his bloodshot eyes. It’s a condition caused by breaking blood vessels in the eye, a hazard of deepsea diving that has not been overcome yet.”
Sir Jelbart shook his head. “Astounding,” he muttered.
“You were absolutely right in your theory, Sir Jelbart. The only problem I had was to discover how it was done. A search of the house will probably supply the evidence,” Holmes said airily. “You will find cameras, projectors, the electrical batteries he ferried out to the cave to work the projector, and above all, the film of the young woman dancing.”
