“What’s the new find, Dorothy?” asked Tom, smiling at her eagerness.

“A letter from Carl Denckel,” she replied.

“Impossible!” cried Tom. “The dear old boy died nine months ago.”

“But this was written nearly a year ago,” she rejoined. “Look at this envelope.”

The big blue square inscribed in crabbed German script was filled with addresses. “See,” said Dorothy. “He thought you were still at Columbia, so he addressed it to Columbia, America, forgetting New York. His ‘u’ was so much like an ‘o’ that they sent it to Colombia, South America. It travelled half over South America, and then they sent it up here. It went to three or four Columbias and Columbus’s in different States. Finally some bright man sent it to the University, and they sent it over to you. It’s for you all right.”

“Read it, Dorothy. What does he say?”

“An Herrn Doktor Thomas Haldane.

“Lieber Professor:—Es geht mir an den tod—” She had gone thus far in the German, when she glanced up and saw my uncomprehending face. “The German too much for you?” she asked. “I’ll translate.” She went on rapidly in English.

“To Doctor Thomas Haldane.

“Dear Professor:

“I am about to die. My physician tells me that I have less than a month left to work. I have just completed the apparatus which had engaged my attention exclusively for the last six years,—my wave-measuring machine. By means of this machine, any wave of a given intensity may be registered as regards its velocity and power.”

“If you don’t mind, I’d like to break in right there,” I interrupted.

“Go on,” said Tom.

“What kind of waves is he talking about? Is this some sort of a machine for measuring the tides down on the beach, or what is it?”

Tom laughed. “Not exactly,” he said. “Denckel’s machine is to measure waves like those of electrical energy. You know, don’t you, that we believe wireless messages go from one station to another by means of ether waves, as they call them?”

I nodded.

“Well, Denckel means to measure waves of that kind, and waves that would come from an arc lamp or a dynamo or a piece of radium or anything like that. It’s to measure the same sort of wave that charged the reflectoscopes, in short—See?”

“I do,” I answered. “But—”

“Hold on till we finish the letter, Jim, and we’ll go over it.” I subsided and Dorothy went on.

“More than that, the distance from the point of generation of the wave, and the exact direction from which it comes, can be ascertained. It is, as you may see, the unique discovery of the past five years. In computing and making it, I have used some discoveries made by my late colleague, Professor Mingern. At his death, six years ago, he passed his work on to me. Now that my death approaches, I pass my work on to you. I have had many pupils in my long life, but none so worthy, none so able to carry on the work, as you, my dear friend and pupil. Farewell.

“Carl Denckel.”

“He was as fine an old chap as ever I knew,” said Tom, with deep feeling. “To think of his sending that to me. But what can have happened to it?”

Dorothy stood with a second sheet in her hand. “Here’s something about it,” she said. “Manuscripts sent under cover to same address, apparatus sent to New York via Hamburg-American line.”

“Then the first thing to do is to find the apparatus,” said Tom. “We can send a trailer after the manuscript, but we can’t bank on getting it. I’ll go down to the custom-house to-morrow morning. What a blow to science, if the whole thing were lost.” “But,” he went on suddenly, “isn’t it extraordinary that this should come along just now? It helps us a whole lot.”

“That is so,” remarked Dorothy reflectively. “We ought to be able to tell just where ‘the man’ is every time.”

“Once more I humbly confess my ignorance,” I remarked, “but will you kindly enlighten me as to the way in which this is to help us in the search for the man?”

“Certainly,” said Dorothy smiling. “We know that the reflectoscopes were charged by a wave which ‘the man’ sent out from some definite spot. Theoretically, that place might be anywhere in the world. Practically, it’s probably somewhere not many miles from the ship he is destroying. But it is somewhere. His waves start from some definite point. There is some single point of generation. Now, with this machine, I ought to be able to find out just where the place is from which the wave starts, and not only within a hundred miles, but within a very brief space. Say, for instance, we had the machine in London, I could tell that ‘the man’ started his waves from Sandy Hook, and not from Hell Gate. That power of fixing the exact position of ‘the man’ gives us a tremendous step.”

“Absolutely tremendous,” I cried, and Tom chimed in, his eyes blazing with enthusiasm. “Here’s to the successful working out of the new clue.”

The announcement of dinner made rather an anti-climax to our discovery.

Tom laughed—“Well, we’ve got to eat, anyway. Come on.”

No feast could equal a dinner with Dorothy as hostess. Never did her sweet face look more charming than when she presided at her own board. The talk soon became confined to technicalities, as Dorothy and Tom discussed the possibilities of the new apparatus, and I sat watching Dorothy’s expressive face, as she talked of velocities and lengths, methods of generation and of control. But her absorption in her subject lasted but a brief time. Dinner over she turned to the piano. Then for two hours her music wafted me through many a lofty old Iberian turret.

As I walked to my rooms from the Haldanes’, I revelled in every breath of the city air. The very noises of the street exhilarated me, as I strolled along, one of the crowd, and a free man. The unexpected setback of my arrest now safely over, I could attack the new clue with eagerness, and the early morning found all three of us at the Hamburg-American pier. No trace of any such invoice as Carl Denckel had described was to be found in any of the office records. Book after book was searched for some account of the shipment, but in vain. As a last resort, we went out to the huge warehouses and searched them, up and down, back and forth. The morning passed in unavailing work. We swung up town to lunch, and then turned again to our task. The most unruly of warehouse men turned into an obedient slave at Dorothy’s behest, and from one long bare shed to another we passed, escorted by a retinue of willing workers. We paused at length at the end of the pier, where the big doors looked out on the water, glowing beneath the sun. The burly Irishman who had been our escort from the first took off his cap and wiped his wet brow.

“I’m feared it’s no use, mum,” he said apologetically. “Shure and I’d go on fer hours huntin’ fer you, if ’twas anny use, but it’s niver a bit. We’ve been iverywhere that a machine loike thot could be.”

With regret we gave up our futile search and retraced our steps towards the waiting car. We had seated ourselves and were watching the chauffeur, as he bent to crank the machine, when we heard a cry behind us. We turned and saw our guide running at full speed, his arms waving wildly. As he came near he shouted, “There’s just wan chance. I remembered meself that a while ago, there was a lot of old unclaimed and seized stuff sint to the appraiser’s stores to be auctioned off. They’ve been havin’ the sale the day and to-morrer at three. You might find it there.”

“We’ll try,” said Tom, and we quickly ran across to the auction. As we stepped inside the room, we saw a motley assembly before us,—junk dealers, Jew peddlers, old clothes men, clerks, buyers of hardware houses, and a few reporters. A lot of fancy door bolts were being sold, and competition was running high. Foremost among the bidders was a woman who was evidently an old acquaintance of the auctioneer’s. She was a queer compromise between the old and the new. On the tight brown wig of the conservative old Jewish matron was set askew a gay lacy hat, such as adorns the head of an East Side belle on a Tammany picnic. Her costume was in harmony with her head gear, consisting of a black skirt, and a flaming red waist trimmed with gorgeous gold embroidery. Her keen eyes twinkled at the badinage of the auctioneer, and her face showed an acumen hard to overcome. One by one the bidders withdrew, till only this woman and another Jew, an old man, were left. The price was mounting by cents, till the last limit of the woman’s purse seemed reached, and she stopped bidding. In vain the auctioneer tried to rouse her to another bid. “Twenty-six, twenty-six. Absolutely thrown away at twenty-six. Come, Mrs. Rosnosky, give me thirty. You can sell the lot for fifty. It’s the chance of your life.” Mrs. Rosnosky was not to be moved.

Again the auctioneer appealed in vain and, glancing around him, he reached down beside him and brought up a dusty broken mixture of wires and metals, of cones and cylinders. “Here, Mrs. Rosnosky! Make it thirty, and I’ll throw this in.”

As the eyes of my companions lighted on the mass, they started forward. Tom opened his mouth to bid, but, before the words could come from his lips, Mrs. Rosnosky had nodded decisively. Her competitor behind her had shaken his head, and the cry of “Sold to Mrs. Rosnosky at thirty” came through the air. Tom looked at Dorothy expressively, and she nodded back and whispered. “It looks as if it might be the machine. We’ll get it from her.”

Clearly Mrs. Rosnosky had obtained all she desired. Motioning to a boy in the rear, she stepped to the clerk’s desk, paid her money, and started to remove her goods by the aid of her helper, paying no attention to the cries and movement about her. We followed the machine as it left the building, and stood on the opposite side of the street, as the boy and the woman filled an old express cart with their purchases.

Last of all they put in the medley of apparatus on its wooden stand. As they placed it on the wagon, I lounged across the street. “Want to sell that?” I asked, pointing to the apparatus.

“Not for anything you want to pay, young man,” came back the answer, to my surprise.

“I’ll give you five dollars for it,” I said.

Mrs. Rosnosky vouchsafed no reply to my offer, and mounted the seat.

Tom, who had heard the conversation, came hurrying across. “What do you want for it?” he asked.

“Five thousand dollars,” replied Mrs. Rosnosky, clucking to her horse. Tom seized the bridle.

“Nonsense, woman. You got that for nothing, and you ask five thousand dollars. We’re willing to give you a fair price, but that’s robbery.”

Mrs. Rosnosky looked at us keenly. “If you really want to talk business,” she said, “say so. That’s worth five thousand dollars.” She seized a cylinder, with a sudden gesture, ripping it from its place. She pointed to a band of silvery metal round it. “That’s platinum,” she said. “There’s five thousand dollars in that stuff for me. If you want it, you take it now or not at all. I know what platinum is worth.”

Dorothy, who had crossed the street and stood beside us, broke in. “Take it, Tom,” and Tom obeyed, with a nod.

He turned to the woman. “I haven’t five thousand or five hundred dollars with me, but if you’ll come up town, I’ll get five thousand for you.”

Mrs. Rosnosky would not part with the apparatus. Tom would not let it out of his sight. Either Tom had to mount the express wagon, or Mrs. Rosnosky had to come in the motor car. The latter was her choice, and Mrs. Rosnosky had the joy of sitting enthroned in a big blue motor, while we sped up town. The bank had long since been closed, and for swiftness and surety we decided to run up to Tom’s club. There he was able to cash a check. Mrs. Rosnosky bore the gaze of the few men who lingered around the big club windows with a perfect and patronizing equanimity, and, her money in hand, finally descended from the car and returned to her East Side abode, a richer woman.

Tom heaved a sigh of relief as we started off again. “Thank heaven that red and gold nightmare with the wig is gone. She was a clever one, though. Who’d have thought of her recognizing platinum at a glance. I didn’t, I confess, under all that dust. Poor old Denckel, his heart would break if he could see the machine now.”

“Never mind, Tom,” said Dorothy, as he gazed ruefully at the wreck before him. “I think we can get that together again. But how I wish we had the data in the manuscript!”