“Your idea paid off, Chief’s Assistant,” the Kholghoor SecReg Subchief told him.  “The slaves gave us a lot of physical description data on the estate, and told us about new fields that had been cleared, and a dam this Lord Ghromdour was building to flood some new rice-paddies.  We located a belt of about five parayears where these improvements had been made:  we started boomeranging the whole belt, time line by time line.  So far, we have ten or fifteen pictures of the main square at Sohram showing Croutha with firearms, and pictures of Wizard Trader camps and conveyer heads on the same time lines.  Here, let me show you; this is from an airboat over the forest outside the equivalent of Sohram.”

There was no jungle visible when the view changed; nothing but clusters of steel towers and platforms and buildings that marked conveyer heads, and a large rectangle of red-and-white antigrav-buoys moored to warn air traffic out of the area being boomeranged.  The pickup seemed to be pointed downward from the bow of an airboat circling at about ten thousand feet.

“Balls ready to go,” a voice called, and then repeated a string of time-line designations.  “Estimated return, 1820, give or take four minutes.”

“Varth,” Ranthar Jard said, evidently out of the boat’s radio.  “Your telecast is being beamed on Dhergabar Equivalent; Chief’s Assistant Verkan is watching.  When do you estimate your next return?”

“Any moment, now, sir; we’re holding this drop till they rematerialize.”

Vall watched unblinkingly, his fork poised halfway to his mouth.  Suddenly, about a thousand feet below the eye of the pickup, there was a series of blue flashes, and, an instant later, a blossoming of red-and-white parachutes, ejected from the photo-reconnaissance balls that had returned from the Kholghoor Sector.

“All right; drop away,” the boat captain called.  There was a gush, from underneath, of eight-inch spheres, their conductor-mesh twinkling golden-bright in the sunlight.  They dropped in a tight cluster for a thousand or so feet and then flashed and vanished.  From the ground, six or eight aircars rose to meet the descending parachutes and catch them.

The screen went cubist for a moment, and then Ranthar Jard’s swarthy, wide-jawed face looked out of it again.  He took his pipe from his mouth.

“We’ll probably get a positive out of the batch you just saw coming in,” he said.  “We get one out of about every two drops.”

“Message a list of the time-line designations you’ve gotten so far to Zulthran Torv, at Computer Office here,” Vall said.  “He’s working on the Esaron Sector dope; we think a pattern can be established.  I’ll be seeing you in about five hours; I’m rocketing out of here as soon as I get a few more things cleared up here.”

Zulthran Torv, normally cautious to the degree of pessimism, was jubilant when Vall called him.

“We have something, Vall,” he said.  “It is, roughly, what Dr. Nentrov suggested—­each of the intervals between the designations is a very minute but very exact fraction of the difference between lesser designation and the base-line designation.”