"What's the matter, Miss Ross?"
"Of course," she said softly. "Of course! What a fool I am! Now I see.
"What do you see?" I demanded.
"The coffee. How it was tampered with. I'd just served Colonel Harrison—he was in the rear seat, so he was the last to be served -when he wrinkled his nose and asked if I could smell something burning. I couldn't, but I made some sort of joke about something burning on the galley hotplate and I'd just got back there when I heard the Colonel calling, and when I looked round he had the door of the starboard washroom open and smoke was coming out. Not much, just a little. I called the captain, and he hurried aft to see what it was, but it was nothing serious, just a few papers burning—somebody had been careless with a cigarette, I suppose."
"And everybody rose out of their seats and crowded to have a look?" I asked grimly.
"Yes. Captain Johnson ordered them all back to their seats -they were upsetting the trim of the plane."
"And you didn't think this worth mentioning to me," I said heavily. "No importance at all?"
"I'm sorry. It—it did seem unimportant, unrelated to anything. That was hours before the crash, so—"
"It doesn't matter. Who could have gone into the galley then -anybody in the front seats, I suppose?"
"Yes. They all seemed to crowd down past the middle—"
"They? Who were 'They'?"
"I don't know. What—why do you ask?"
"Because by knowing who was there, we might find out who wasn't."
"I'm sorry," she repeated helplessly. "I was a little upset for a moment, then Captain Johnson was in front of me shooing everybody back to their seats and I couldn't see."
"All right." I changed my approach. "This was the men's washroom, I take it?"
"Yes. The powder room is on the port side."
"Can you remember who went in there, say, any time up to an hour beforehand?"
"An hour? But the cigarette end—"
"Do you believe now that the fire was caused deliberately?" I asked.
"Of course." She stared at me, wide-eyed.
"Right. And we're dealing, obviously, with hardened professional criminals. The whole success of their plan depended on causing this excitement. Do you for a moment believe that they were going to let the whole thing hinge on the mere off-chance of a smouldering butt-end setting some papers alight—especially setting them alight at the correct moment?"
"But how—"
"Easy. You can get a little plastic tube with a central composition shield dividing it into two compartments. In one compartment you have a free acid, in the other a different acid enclosed in a glass tube. All you have to do is to crush the tube, break the glass, drop the tube in your chosen spot, walk away and after a predetermined time the acid that was in the glass eats through the shield, meets the other acid and starts a fire. It's been used hundreds of times, especially in war-time sabotage. If you're an arsonist looking for a cast-iron alibi and want to be five miles away when the fire starts, it's the perfect answer."
"There way a funny smell—" she began slowly.
"You bet there was. Can you remember who went there?"
"It's no good." She shook her head. "I was in the galley most of the time, getting the meal ready."
"Who were in the front two seats—those nearest the galley?"
"Miss LeGarde and Mr Corazzini. And I'm afraid that's not much help. We know Marie LeGarde can't have had anything to do with it. And Mr Corazzini is the one person I'm sure didn't leave his seat before dinner. He had a gin soon after take-off, then switched off his reading light, draped a newspaper over his head and went to sleep."
"Are you sure?"
"Quite sure. I always peek through the cabin door from time to time, and he was always there."
"That seems to cut him out," I said thoughtfully. "And reduce the number of suspects—though, I suppose, he could still have got an accomplice to plant the acid tube." Then, suddenly, I had what was, for me, an inspiration. "Tell me, Miss Ross, did anyone ask you earlier in the evening when dinner would be?"
She looked at me for a long moment before answering, and even in the fading light of the aurora I could see the understanding coming into her eyes.
"Mrs Dansby-Gregg did, I'm sure."
"She would. Anyone else."
"Yes. I remember now." Her voice was suddenly very quiet. "Colonel Harrison—but he doesn't count any more—and Mr Zagero."
"Zagero?" In my excitement I bent forward until my face was almost touching hers. "Are you sure?"
"I'm sure. I remember when he asked me, I said, "Are you feeling peckish, sir?" and he grinned and said, "My dear air hostess, I always feel peckish."
"Well, well. This is most interesting."
"Do you think Mr Zagero—"
"I'm at the stage where I'm afraid to think anything. I've been wrong too often. But it's a straw in the wind all right—a straw about the size of a haystack.. . . Was he anywhere near you when the radio fell? Behind you, for instance, when you rose and brushed against the radio table?"
"No, he was by the hatch, I'm sure of that. Could he—"
"He couldn't. Joss and I worked it out. Somebody had pushed one of the table hinges right home and the other until it was at the critical point of balance. Then as you stood up he pushed the other in. From a distance. There was a long-handled brush lying there -but it had no significance for us at the time.. . . When you heard the crash you whirled round, didn't you?" She nodded without speaking.
"And what did you see?"
"Mr Corazzini—"
"We know he dived for it," I said impatiently. "But in the background, against the wall?"
"There was someone." Her voice was barely more than a whisper. "But no—no, it couldn't have been. He'd been sitting dozing on the floor, and he got the fright of his life when—"
"For heaven's sake!" I cut in harshly. "Who was it?"
"Solly Levin."
The brief twilight of noon came and went, the cold steadily deepened and by late in the evening it seemed that we had been on board that lurching, roaring tractor all our lives.
Twice only we stopped in the course of that interminable day, for refuelling at 4 p.m. and 8 p.m. I chose these times because I had arranged with Joss that I would try to contact him every fourth hour. But though we set up the apparatus outside while Jackstraw was refuelling and Corazzini sat astride the bicycle seat and cranked the generator handle while I tapped out our call sign for almost ten unbroken minutes, no shadow of an answer came through. I had expected none. Even if by some miracle Joss had managed to fix the set, the ionosphere turbulence that had caused the aurora would have almost certainly killed any chance of making contact. But I'd promised Joss, and I had to keep faith.
By the time I made the second try, everyone, even Jackstraw and myself, was shaking and shivering in the bitter cold.
Normally, we wouldn't have felt it much—in very cold weather we wore two complete sets of furs, the inner one with the fur inside, the outer with the fur outside. But we'd given our extra pairs away to Corazzini and Zagero—furs were essential in that ice-box of a tractor cabin—and suffered just as much as the others.
Occasionally, someone would jump down from the tractor and run alongside to try to get warm, but so exhausted were most from sleeplessness, hunger, cold and eternally bracing themselves against the lurching of the tractor, that they were staggering from exhaustion within minutes and had to come aboard again. And when they did come aboard, the sweat from their exertions in such heavy clothes turned ice-cold on their bodies, putting them in worse case than ever, until finally I had to stop it.
It grieved me to do what had to be done, what I saw must be done, but there was no help for it. The weariness, the cold and the sleeplessness could be borne no longer. When I finally gave the order to stop it was ten minutes after midnight, and we had been driving continuously, except for brief fuel and radio halts, for twenty-seven hours.