Stacey's voice was as dry as ever, "Busy, Paul?"

"Just polishing up my talk," he said. "I'm due to lecture in an hour."

"Well, don't be nervous."

"I'd be less nervous if I knew what was going on."

"This might help. First, your corpse was none other than a three-time loser named Clarke and a pot full of aliases, none of which are worth mentioning. As dead as a mackerel."

"What are we going to do about him?"

"It's been done."

"How?"

"Don't ask."

"But isn't this disposing evidence?"

"Sure. But if any crime has been committed, he did it, or attempted to. He is no loss to the community."

"But that is against the law."

"So is kissing a woman who is of no relation to you, in public in this state," chuckled Stacey. "You'll only get involved in a lot of official curiosity if you disclose the death. That will get you a grilling and a mess of suspicion to fight against, while the birds who set him on you will be forewarned. They'll be free to plot further while you are busy defending an innocent stand. Besides," he added with another chuckle, "there is nothing like making them chew a fingernail, wondering just where their plans went afoul. Let them scurry around instead of you. If I guess right, they are not quite certain whether the man now talking to me is Paul Grayson, bona fide, or their little masquerader."

"But why, for the Love of Heaven?"

"Look, mes infante innocente, this is twice that you've met a character made up to resemble you. This means an intended masquerade. I don't know why. But I'll bet a hat that there is a motive to it all."

The last was so obvious that Paul saw no reason to comment. Stacey continued, "One more item before I go away and leave you to your test tubes. Nora Phillips."

"Yes?" came Paul's eager reply.

"Posing as a man making a survey, I, me, myself twiggled on the doorbell at 7111 Bridge Avenue this afternoon, after canvassing the entire neighborhood up to that point to make it look good."

"Go on."

"Nora Phillips is their niece. The elderly gentleman said so. She parked her car there for the time being since her pappy, brother to his wife, is desperately ill on Neosol."

"So?"

"She'll be back, but they did not know when."

"Get her address?"

"Couldn't get too curious. No."

"Damn."

"Why?"

"Somehow, Nora is tied up in this. On my side."

"Okay, I'm going to follow one other lead. Take it easy, Paul, and give the physicists hell."

"I'll try."

"I will begin at the beginning," smiled Paul, wishing he had the air of a professional lecturer and the literary ability of an author, "space was first conquered by rocket propulsion. Eventually a base was established on Luna and the space stations set up. Operating in space, the physicists discovered the supervelocity drive, which like electricity, was used long before people began to understand it.

"The rocket is a clumsy device and ill-adapted to anything but limited, professional use. But the superdrive made space travel practical for the ordinary man. Space was truly conquered then, and today men live on Venus and on Mars. Precariously and uncomfortably, but they live there. Men have spread throughout the solar system, working in mines and medicinal farms and jungles. Their tenure of employment is dictated by the rigors of life on these inimical planets of Sol.

"With the superdrive, explorers chased through the nearer galaxy, seeking a planet suitable for colonization. While most stars have been found to have planets, there was not one found that filled the bill until they located Neosol and Neoterra, both of which resemble Sol and the earth to a fine degree.

"Radio linked the colonies of Sol, and after Neosol was colonized, radio linked its spread-out colonists.

"Forty years ago, Carrington discovered the Z-wave, an outgrowth of the superdrive. Then the instantaneous Z-wave replaced the slow radio transmissions that required teletype and code communications, and voice to voice contacts prevailed throughout the solar system, and throughout the system of Neosol.

"But the Z-wave did not cross the gulf of interstellar space, and years of experimentation followed, all of which failed. Then, twenty years ago, Chadwick Haedaecker suggested the theory now known as Haedaecker's Theory, which tended to show that the Z-wave propagated because of the fields of force generated in the central cores of stars. Since that date, only desultory attempts have been made to test the Z-wave in deep space. Experimentation had stopped, for all practical purposes. About the only people who have given the matter much thought are students of theory, and a couple of hardy souls like myself, who—I have been accused and of which I must admit—hoped to become rich and famous by making some extraordinary discovery.

"I will now advance the idea that I hope will be eventually known as Grayson's Principle.

"The basis of Grayson's Principle is that the Z-wave will not propagate between points that have not previously been linked by electromagnetic waves!"

This caused a storm in the auditorium. A showing of frantic hands flowered above the sea of faces and the hall broke into a growling murmur of muttering voices, discussing pro and con.

The chairman came forward and spoke to Paul: "Shall I call order, or would you prefer to have a mid-lecture discussion?"

Paul smiled nervously. "I was prepared for this," he said. "The rest of this will run better if we get this one point settled. It will be too long from now to the end of my lecture to make these men hold their questions."

"Good!" smiled Thorndyke. He rapped for order. "Gentlemen," he said, speaking over the incomplete attention, "Mister Grayson has just made a rather shocking statement, which is cause for controversy. He has suggested himself that a mid-lecture period of questions will hasten our understanding of his theory."

There was a burst of applause and the flowering of hands went up again.

"Edwin Johnson," said the first man naming himself. "Granting that it takes light one hundred and forty years to cross between here and Neosol, I suggest that the entire galaxy has been coupled by electromagnetic waves for two thousand million years."

"I said 'linked'," explained Paul easily. "This question is one that stumped me for a long time and was possibly the one thing that prevented the advancement of the principle long before. But the detectors we employ to detect those frequencies we term 'light' are not similar to those we use for the longer frequencies of radio, even though both are electromagnetic waves. Light will not travel along a conductor, although it is true that the longer waves will be transmitted through a waveguide made of dielectric that is transparent to them. Ergo, it is the means we use to handle these frequencies that establish the 'linkage' rather than the medium or the wave itself."

"I am Fred Hughes," said the second. "Do you mean to state that the Z-wave has never been known to operate between points not previously linked by radio?"

"That is right."

"You've investigated everything?"

"Mine is negative evidence, I admit. This is why it is hard to establish as truth. But remember, the solar system was linked by radio long before the Z-wave was discovered."

"How about spacecraft?"

"Once the Z-wave linkage is established by its forerunner of radio, it is complete and can not be broken."

"A spacecraft employs radio until it reaches the superdrive point. Then—?"

"I have had no opportunity to check this point as yet. I believe it has to do with the doppler effect. Remember that the selectivity of the radio used in space is such that a doppler shift will not detune it grossly. Obviously, superdrive will completely ruin such tuning."

"But this has been tried?"

"Yes. It was once hoped that we could link to Neosol that way. The connection failed as soon as the ship entered superdrive."

"But interplanetary ships employ Z-wave."

"I have had no opportunity to check this on an interstellar scale. I shall at the earliest opportunity. It is my belief that the radio beacons between earth and Venus, for instance, are maintained at both ends by receiver and transmitter, the receiver being used to control the transmitter and keep the beam properly centered and to check its presence. This contact made in both directions along the spacelanes, maintains the operation of the Z-wave on the ship, running at higher than the speed of light. The radio is, of course, useless. But the Z-wave, propagating at some figure we cannot measure yet, suffers no doppler effect."

"I am Grant Lewdan," said the third. "Has the Z-wave ever been tried in the depths of interstellar space?"

"Yes."

"Did it work?"

"Up to a certain point."

"Then why didn't they pursue it?"

"This answer demands that we all understand the psychology of the human being and the mechanics of the scientific method. I will answer this first by analog:

"Presume for the moment that radio cannot propagate across a space that communication has not crossed previously. Then consider Marconi on his first attempt to send radio waves across a hundred feet of vacant lot. What is the method used in testing an unknown method of communication? The transmitter is started, and the operator either calls or signals by waving his hands, that the transmitter is now working. As soon as the hand signal is seen the receiver is checked, found to be working. Remember, this radio works because of the previous linkage by communication in accordance with our hypothesis. Success is noted.

"Then the distance is increased by many miles from mountain top to mountain top and a blinker system is employed to carry the experimental information back and forth. Again the transmitter is started and the blinker used to inform the other party that he is to watch for the radio's response. Again, it works, since communications have been established. For the third time, the radio equipment is separated by the antipodes of the earth and a telephone or telegraph connection is established. Again the transmitter is started and the signal is sent; again there is success. Now, gentlemen, the inference is that radio will work to a distance encompassing the entire earth.

"Now postulate a spacecraft taking this same equipment to the Moon. Lacking radio, no means of communication are practical. Let us say Venus instead, gentlemen, since a magnesium flare might be used from Luna. So, on Venus, there is no means of communication other than radio, which depends first upon the establishment of other means of communication ere it will work.

"A failure is noted.

"Now," smiled Paul, "this is what happened in deep space. I would like to read an excerpt from the Communications Expedition Number Three:

"'... Two spacecraft were dispatched from Pluto and proceeded outward for approximately one light hour as established by the timing wave from Pluto. The Z-wave was tested and found available ...' here follows a couple of columns of figures regarding signal strength and so on. '... At one hundred light hours, the same test was made and found successful....' At this point, gentlemen, remember that they used the timing wave from Pluto to establish their distance, which established radio communications.

"Now, remember the techniques employed in such tactics. It is not necessary for the spacecraft to wait a hundred hours for the arrival of the wave. The wave is sent forth a hundred hours before the ship gets there so that no waiting time will be necessary. In fact, they tried it at one thousand light hours, since that was the distance previously established by the timing wave from Pluto. Again it worked successfully. The timing wave had been started about twelve hundred hours before, and as usual, it was so-coded that at any point along the line, the ship could stop, listen in, and mark the time. It was, sort of, like a rope with a series of knots in it.

"Having made this approximation, the ships went into deep space, about three light years distant from Sol where they were not closer than three light years from any star. At this distance, the radio signal from Pluto had not arrived, and they had no idea of waiting for three years for it since they did not conceive of Grayson's Principle. But they communicated with one another.

"One light hour, waiting for the timing wave, and it was shown successful. I read again:

"'At ten light hours, there was no success. Our technical officer then spent many hours checking his equipment while the navigating officer used the scooter to run back and forth with Spacecraft BurAst 7,331 to ascertain whether the Z-wave gear was in operation. The arrival of the timing wave distracted his attention for a period of about five minutes during which he established the separation between the two ships. Upon returning to the Z-wave equipment and completing his many investigations as to sensitivity and function, he was satisfied that it was in operating shape. At this point it was tried again, and twenty minutes of two-way conversation ensued, proving that the Z-wave was operative at a distance of at least one hundred and seven point three eight light hours, as established by the timing wave. Second Technical Sergeant Frankford Brown was reprimanded for removing the Z-wave gear from the rack and panel and placing it on the test-bench and thus wasting many hours.

"'The equipment was again tried at one thousand light hours, but no success was found even though ten or twelve hours ensued during the listening test. Because our supplies were now running low, the test was abandoned at this distance and....' Here, gentlemen, follows an account of at least a hundred hours of testing constantly with the two ships at varying distances. Success came sometimes, complete failure at others. There is a complete set of spacial maps, but these show no contours of signal strength nor correlation.

"Only a man who believed that the Z-wave followed radio communications would establish such a correlation."

"And how was this correlation located?" asked Lewdan.

"Because I noted that when failure came, it was noted at distances, 'Approximately ten light hours, ... fifteen light hours ... three light hours.' But when success came, it came at, 'Seven, point nine-eight, or fourteen, point four-two light hours.' In other words, gentlemen, they knew their separation only when success came and they could measure the distance accurately by the radio timing wave."

During this time, the hands were dropping as the answer to one question answered the questions of others. At the end, there were no more hands upraised. Thorndyke then said: "We are now ready to continue with this lecture."

Paul took a gulp of water and started off again:

"I have one other item to bring forth. I have been working with the galactic survey—" and Paul went on for many minutes, explaining in detail what they had been doing and why. He finished up with his determination to test the Z-wave in accordance with his own theory. Then he said: "I have here a recording made over the Z-wave receiver I took with me to Proxima Centauri I. As you know, the interstellar beacon was erected on the top of the Z-wave Central Building. No visual connection seems necessary, but we all know that dielectric or permeabilic coupling serves in many places far better than a conducting link; it is my idea that similar factors to permeability and capacity will be found in the Z-wave. However Z-wave Central is all supplied from one power line. Here is a physical connection.

"Upon my arrival at the Proxima Station, this Z-wave recorder was started with the radio. You will hear, in the recording, which was made through a microphone to pick up the room-sounds as well as the Z-wave broadcast, the arrival of the radio signal from Terra, the timing signals, a few of my own comments made, I must admit, in the stress of enthusiasm, and finally, the terran side of an interplanetary Z-wave conversation between a woman and her man. While I deplore any public airing of the personal affairs of any man and woman, this is of the utmost importance to Civilization, while the subject of her conversation is such that she can have only pride in having it made into history. For," he added softly, "hers is the voice of true, honest affection, faith and trust in her mate, and such is well worthy of a monument in the halls of history!"

There was a round of good-natured applause at this moment. And then the recording rang out:

"... but it won't be long, my dear ... of course, it seems so.... Do that, by all means.... In a month, you say?... I'm very happy about that...." the signal faded and in the background the audience could hear the measured cadence of the radio timing signals, with a few of Paul's own personal comments of exultation. Then the Z-wave signal came in again, "... Terry said so.... How do I know?... By all means, my dear...."

Paul turned the recording off amid the thunderous roar of applause.