"Stop it, man," Holmes said sharply. "This self-destructive blame is hardly helpful. For now, we should concentrate on the facts of the case."
Holmes took Bryson to the entrance cut in the capsule. With obvious reluctance the engineer picked his way to the crude doorway. The light inside cast his trembling cheeks in sharp relief. I saw how he looked around the walls of the cabin, at the remnants of the couch on the floor. Then he stood straight and looked at Holmes, puzzled. "Has it been cleaned?"
Holmes pointed upwards.
Bryson pushed his neck through the doorway once more and looked up at the ceiling of the capsule. When he saw the human remains scattered there he gasped and stumbled back.
Holmes said gently, "Watson, would you-"
I took Bryson's arm, meaning to care for him, but he protested: "I am all right. It was just the shock."
"One question," Holmes said. "Tell me how the cable was cut."
"Tarquin was working the torch," he began. "Under my direction. The job was simple; all he had to do was snip out a faulty section of an oxygen line."
"Are you saying Ralph's death was an accident?"
"Oh, no," Bryson said firmly. "It was quite deliberate." He seemed to be challenging us to disbelieve him.
"Tell me the whole truth," said Holmes.
"I was not watching Tarquin's every move. I had given Tarquin his instructions and had left to take breakfast before progressing to another item of work."
"What exactly did you tell him to do?"
He considered, his eyes closing. "I pointed to the oxygen line, explained what it was, and showed him what he had to do. The air line is a purple-coded cable about a thumb's-width thick."
"Whereas the support cables-"
"Are all orange coded, about so thick." He made a circle with his thumbs and middle fingers. "It is hard-impossible-to confuse the two."
"Did you not see what he was doing?"
"I was at breakfast with Mrs Brimicombe when it happened. I expected to be back, however."
"Why were you not?"
He shrugged. "My breakfast egg took rather longer to cook than usual. I remember the housekeeper's apology."
Wells tutted. "Those wretched eggs again!"
"At any event," Bryson said, "I was only gone a few minutes. But by the time I returned Tarquin had sliced clean through the main support. Then the shearing began."
"So you clearly identified the gas line to Tarquin."
"I told you. I pointed to it."
"And there is no way he could have mixed it up with the support cable?"
He raised his eyebrows. "What do you think?"
I scratched my head. "Is it possible he caught the support somehow with the torch, as he was working on the gas feed?"
He laughed; it was a brief, ugly sound. "Hardly, Doctor. The support is about four feet from the air line. He had to turn round, and stretch, and keep the torch there, to do what he did. We can go up to the gantry and see if you like." He seemed to lose his confidence. "Look, Mr Holmes, I do not expect you to believe me. I know I am only an engineer, and Tarquin was Ralph's brother."
"Bryson-"
"But there is no doubt in my mind. Tarquin quite deliberately cut through that support, and ended his brother's life."
There we left our inquiries for the day.
I fulfilled Holmes's request regarding the dog Sheba. On a cursory inspection I found the poor animal's limbs to be spindly and crooked from so many breaks. I collected a sample of her urine and delivered it to the Chippenham general hospital, where an old medical school friend of mine arranged for a series of simple assays. He had the results within the hour, which I tucked into my pocket.
I rejoined my companions, who had retired to the "Little George" hostelry in Chippenham for the evening. They had been made welcome by a broad-bellied, white-aproned barman, had dined well on bread and cheese, and were enjoying the local ale (though Holmes contented himself with his pipe), and talking nine to the dozen the while.
"It is nevertheless quite a mystery," said Wells, around a mouthful of bread. "Has there even been a murder? Or could it all be simply some ghastly, misunderstood accident?"
"I think we can rule that out," said Holmes. "The fact that there are such conflicts between the accounts of the two men is enough to tell us that something is very wrong."
"One of them-presumably the murderer-is lying. But which one? Let us follow it through. Their accounts of the crucial few seconds, when the cable was cut, are ninety per cent identical; they both agree that Bryson had issued an instruction to Tarquin, who had then turned and cut through the support. The difference is that Bryson says he had quite clearly told Tarquin to cut through the air line. But Tarquin says he was instructed, just as clearly, to slice through what turned out to be the support.
"It is like a pretty problem in geometry," went on Wells. "The two versions are symmetrical, like mirror images. But which is the original and which the false copy? What about motive, then? Could Tarquin's envy of his brother-plain for all to see-have driven him to murder? But there is no financial reward for him. And then there is the engineer. Bryson was driven to his dalliance with Jane Brimicombe by the tenderness of his character. How can such tenderness chime with a capability for scheming murder? So, once again, we have symmetry. Each man has a motive-"
Holmes puffed contentedly at his pipe as Wells rattled on in this fashion. He said at last, "Speculations about the mental state of suspects are rarely so fruitful as concentration on the salient facts of the case."
I put in, "I'm sure the peculiar circumstances of the death had something to do with the nature of the Inertial Adjustor itself, though I fail to understand how."
Holmes nodded approvingly. "Good, Watson."
"But," said Wells, "we don't even know if the Adjustor ever operated, or if it was another of Ralph's vain boasts-a flight of fancy, like his trip to the Moon! I still have that vial of Moon dust about me somewhere-"
"You yourself had lunch in the chamber," Holmes said.
"I did. And Ralph performed little demonstrations of the principle. For instance: he dropped a handful of gravel, and we watched as the heaviest fragments were snatched most rapidly to Earth's bosom, contrary to Galileo's famous experiment. But I saw nothing which could not be replicated by a competent conjurer."
"And what of the mice?"
Wells frowned.
"They were rather odd, Mr Wells," I said.
"We can imagine the effect of the distorted gravity of that chamber on generations of insects and animals," Holmes said. "A mouse, for instance, being small, would need the lightest of limbs to support its reduced weight."
Wells saw it. "And they would evolve in that direction, according to the principles of Darwin -of course! Succeeding generations would develop attenuated limbs. Insects like your ant, Watson, could grow to a large size. But larger animals would be dragged more strongly to the ground. A horse, for example, might need legs as thick as an elephant's to support its weight."
"You have it," said Holmes. "But I doubt if there was time, or resource, for Ralph to study more than a generation or two of the higher animals. There was only his wife's unlucky labrador to use as test subject. And when Watson opens the envelope in his pocket, he will find the assay of the urine samples from that animal to display excessive levels of calcium."