Next in a watch gla.s.s he placed some caustic soda and in another some pyrogallic acid, from each of which he took just a drop, as he had done before, inclining the tubes to let the fluid gravitate to the throttle end. Finally in the flame he sealed both the tip and b.u.t.t of the tubes.

"There's a bubble of air in there," he remarked. "The acid and the soda will absorb the oxygen from it. Then I can tell whether I'm right. By the way, we'll have to hurry if we're to be on time to meet Marlowe in the yard," he announced, glancing at his watch as he placed the tubes in his little electric incubator.

We were a little late as the chauffeur pulled in at the executive offices at the gate of the shipyard, and Marlowe was waiting impatiently for us. Evidently he wanted action, but Kennedy said nothing yet of what he suspected and appeared now to be interested only in the yard.

It was indeed something to interest any one. Everywhere were tokens of feverish activity, in office, shop, and slip. As we picked our way across, little narrow and big wide gauge engines and trains whistled and steamed about. We pa.s.sed rolling-mills, forging-machines, and giant shearing-machines, furnaces for heating the frames or ribs, stone floors on which they could be pegged out and bent to shape, places for rolling and tr.i.m.m.i.n.g the plates, everything needed from the keel plates to the deck.

In the towering superstructure of the building slip we at last came to the huge steel monster itself, the Usona. As we approached, above us rose her bow, higher than a house, with poppets both there and at the stern, as well as bracing to support her. All had been done up to the launching, the stem and stern posts set in place, her sides framed and plated up, decks laid, bulkheads and casings completed, even much of her internal fitting done.

Overhead and all about the huge monster was a fairy network of steel, the vast permanent construction of columns and overhead girders.

Suspended beneath was a series of tracks carrying traveling and revolving cranes capable of handling the heaviest pieces. We climbed to the top and looked down at the vast stretch of hundreds of feet of deck. It was so vast that it seemed rather the work of a superman than of the puny little humans working on her.

As I looked down the slip where the Usona stood inclined about half an inch to the foot, I appreciated as never before what a task it was merely to get her into the water.

Below again, Marlowe explained to us how the launching ways were composed of the ground ways, fastened to the ground as the name implied, and the sliding ways that were to move over them. The sliding ways, he said, were composed of a lower course and an upper course, on which rested the "cradle," fitting closely the side of the ship.

To launch her, she must be lifted slightly by the sliding ways and cradle from the keel blocks and bilge blocks, and this was done by oak wedges, hundreds of which we could see jammed between the upper and lower courses of sliding ways. Next he pointed out the rib-bands which were to keep the sliding ways on the ground ways, and at the bow the points on either side where the sliding and ground ways were bolted together by two huge timbers known as sole pieces.

"You see," he concluded, "it is a gigantic task to lift thousands of tons of steel and literally carry it a quarter of a mile to forty feet of water in less than a minute. Everything has to be calculated to a nicety. It's a matter of mathematics--the moment of weight, the moment of buoyancy, and all that. This launching apparatus is strong, but compared to the weight it has to carry it is really delicate. Why, even a stray bolt in the ways would be a serious matter. That's why we have to have this eternal vigilance."

As he spoke with a significant look at Kennedy, I felt that it was no wonder that Marlowe was alarmed for the safety of the ship. Millions were at stake for just that minute of launching.

It was all very interesting and we talked with men whom it was a pleasure to see handling great problems so capably. But none could shed any light on the problem which it was Kennedy's to solve. And yet I felt sure, as I watched Craig, that unsatisfactory as it appeared to Marlowe and to myself, he was slowly forming some kind of theory, or at least plan of action, in his head.

"You'll find me either here or at the hotel--I imagine," returned Marlowe to Kennedy's inquiry as we parted from him. "I've instructed all the men to keep their eyes open. I hope some of us have something to report soon."

Whether or not the remark was intended as a hint to Kennedy, it was unnecessary. He was working as fast and as surely as he could, going over in hours what others had failed to fathom in weeks.

Late in the afternoon we got back to the laboratory and Craig began immediately by taking from the little electric incubator the two crooked tubes he had left there. Breaking off the ends with tweezers, he began examining on slides the two drops that exuded, using his most powerful microscope. I was forced to curb my impatience as he proceeded carefully, but I knew that Craig was making sure of his ground at each step.

"I suppose you're bursting with curiosity," he remarked at last, looking up from his examination of one of the slides. "Well, here is a drop that shows what was in the grooves of that bullet. Just take a look."

I applied my eye to the microscope. All I could see was some dots and rods, sometimes something that looked like chains of dots and rods, the rods straight with square ends, sometimes isolated, but more usually joined end to end in long strings.

"What is it?" I asked, not much enlightened by what he had permitted me to see. "Anaerobic bacilli and spores," he replied, excitedly. "The things that produce the well-known 'gas gangrene' of the trenches, the gas phlegmon bacilli--all sorts, the bacillus aerogenes capsulatus, bacillus proteus, pyogenic cocci, and others, actively gas-forming microbes that can't live in air. The method I took to develop and discover them was that of Col. Sir Almroth Wright of the British army medical corps."

"And that is what was on the bullet?" I queried.

"The spores or seeds," he replied. "In the tubes, by excluding the air, I have developed the bacilli. Why, Walter," he went on, seriously, "those are among the microbes most dreaded in the infection of wounds.

The spores live in the earth, it has been discovered, especially in cultivated soil, and they are extraordinarily long-lived, lying dormant for years, waiting for a chance to develop. These rods you saw are only from five to fifteen thousandths of a millimeter long and not more than one-thousandth of a millimeter broad.

"You can't see them move here, because the air has paralyzed them. But these vibrios move among the corpuscles of the blood just as a snake moves through the gra.s.s, to quote Pasteur. If I colored them you would see that each is covered with fine vibrating hairs three or four times as long as itself. At certain times an oval ma.s.s forms in them. That is the spore which lives so long and is so hard to kill. It was the spores that were on the bullet. They resist any temperature except comparatively high and prolonged, and even resist antiseptics for a long time. On the surface of a wound they aren't so bad; but deep in they distil minute gas bubbles, puff up the surrounding tissues, and are almost impossible to combat."

As he explained what he had found, I could only stare at him while the diabolical nature of the attack impressed itself on my mind. Some one had tried to murder Marlowe in this most hideous way. No need to be an accurate marksman when a mere scratch from such a bullet meant ultimate death anyhow.

Why had it been done and where had the cultures come from? I asked myself. I realized fully the difficulty of trying to trace them. Any one could purchase germs, I knew. There was no law governing the sale.

Craig was at work again over his microscope. Again he looked up at me.

"Here on this other film I find the same sort of wisp-like anaerobes,"

he announced. "There was the same thing on those pieces of gla.s.s that I got."

In my horror at the discovery, I had forgotten the broken package that had come to the hotel desk while we stood there.

"Then it was Gavira who was receiving spores and cultures of the anaerobes!" I exclaimed, excitedly.

"But that doesn't prove that it was he who used them," cautioned Craig, adding, "not yet, at least."

Important as the discoveries were which he had made, I was not much farther along in fixing the guilt of anybody in particular in the case.

Kennedy, however, did not seem to be perturbed, though I wondered what theory he could have worked out.

"I think the best thing for us to do will be to run over to the Belleclaire," he decided as he doffed his laboratory coat and carefully cleansed his hands in an antiseptic almost boiling hot. "I should like to see Marlowe again, and, besides, there we can watch some of these people around him."

Whom he meant other than Gavira I had no idea, but I felt sure that with the launching now only a matter of hours something was bound to happen soon.

Marlowe was out when we arrived; in fact, had not yet returned from the yard. Nor had many of the guests remained at the hotel during the day.

Most of them had been out sightseeing, though now they were returning, and as they began to gather in the hotel parlor Marjorie was again called on to put them at their ease.

Fitzhugh had returned and had wasted no time dressing and getting down-stairs again to be near Marjorie. Gavira also appeared, having been out on a case.

"I wish you would call up the shipyard, Walter," asked Kennedy, as we stood in the lobby, where we could see best what was going on. "Tell him I would like to see him very urgently."

I found the number and entered a booth, but, as often happens, the telephone central was overwhelmed by the rush of early-evening calls, and after waiting some time the only satisfaction I got was that the line was busy.

Meanwhile I decided to stick about the booth so that I could get the yard as soon as possible. From where I stood I could see that Kennedy was closely watching the little manicure, Rae Melzer. A moment later I saw Alma Hillman come out of the manicure shop, and before any one else could get in to monopolize the fascinating little manicure I saw Craig saunter over and enter.

I was so interested in what he was doing that for the moment I forgot about my call and found myself unconsciously moving over in that direction, too. As I looked in I saw that he was seated at the little white table, in much the same position as Marlowe had been, deeply in conversation with the girl, though of course I could not make out what they were talking about.

Once she turned to reach something on a shelf back of her. Quick as a flash Kennedy abstracted a couple of the nearest implements, one being a nail file and the other, I think, a brush. A moment later she resumed her work, Kennedy still talking and joking with her, though furtively observing.

"Where is my nail file--and brush?" I could imagine her saying, as she hunted for them in pretty confusion, aided by Kennedy who, when he wanted to, could act the Fitzhugh and Gavira as well as they. The implements were not to be found and from a drawer she took another set.

Just then Gavira pa.s.sed on his way to his office in the front of the building, saw me, and smiled. "Kennedy's cut you out," he laughed, catching a glimpse through the door. "Never mind. I used to think I had some influence there myself--till the captain came along. I tell you these oldsters can give us points."

I laughed, too, and joined him down the hall, not because I cared what he thought, but because his presence had reminded me of my original mission to call up Marlowe. However, I decided to postpone calling another moment and take advantage of the chance to talk to the house physician.

"Yes," I agreed, as long as he had opened the subject. "I fancy the captain likes young people. He seems to enjoy being with them--Miss Hillman, for instance."

Gavira shot a sidelong glance at me. "The Belleclaire's a dangerous place for a wealthy widower," he returned. "I had some hopes in that direction myself--in spite of Fitzhugh--but the captain seems to leave us all at the post. Still, I suppose I may still be a brother to her--and physician. So, I should worry."

The impression I got of Gavira was that he enjoyed his freedom too much ever to fall in love, though an intimacy now and then with a clever girl like Alma Hillman was a welcome diversion.

"I'm sorry I sha'n't be able to be with you until late to-night," he said, as he paused at his office door. "I'm in the medical corps of the Guard and I promised to lecture to-night on gunshot wounds. Some of my material got smashed up, but I have my lantern slides, anyhow. I'll try to see you all later, though."

Was that a clever attempt at confession and avoidance on his part? I wondered. But, then, I reflected he could not possibly know that we knew he had anaerobic microbes and spores in his possession. I had cleared up nothing and I hastened to call up the shipyard, sure that the line could not be busy still.

Whatever it was that was the matter, central seemed unable to get me my number. Instead, I found myself cut right into a conversation that did not concern me, evidently the fault of the hotel switchboard operator.

I was about to protest when the words I heard stopped me in surprise. A man and a woman were talking, though I could not recognize the voices and no names were used.