"What kind of gas?" Keith asked.

"Its apparent molecular weight suggests a reasonably heavy or complex compound," replied Jag, now looking at one of his monitors. "However, the absorption spectrum is that of normal space dust — carbon grains, and so on." A pause. "There's no discernible magnetic field around the spheres. That's surprising; I had supposed the gas particles might have been held in place by such fields."

"Will the probe be damaged by impact with the particles?" asked Keith.

"It pleases me to respond in the negative," said Rhombus.

"I'm slowing the probe down to avoid that."

Part of the hologram was obscured as the hatch that covered the atmospheric scoop opened up — bad design, that. "Now collecting samples of the material between the spheres," said Rhombus. A few moments later the view cleared as the hatch closed. "Sample bay one full," the Ib reported. "Changing course for atmospheric skim."

The starfield wheeled around as the probe altered its trajectory. One of the circles of blackness was soon in the center of its view. The ebony sphere grew larger and larger until it dominated everything. The probe had headlights, which Rhombus had turned on. They made two murky shafts that penetrated a few meters into the dark, swirling material.

A different part of the view was obscured as another sample hatch opened.

"Taking upper-atmosphere samples," reported the Ib, and then, a moment later, "Sample container full."

"Adequate," said Jag. "Now dive down two hundred meters — or however far you can go safely — and get some more sphere material."

"Doing so, in harmonious peace," said Rhombus's clipped tones.

Everything was pitch-black, except for the twin pools of light from the headlight beams. They were now only penetrating a meter or so. For one brief moment, something solid seemed to be in the probe's path — an ovoid shape the size of a dirigible — but it was gone from view almost at once.

"Depth now ninety-one meters," said Rhombus. "Surprising.

External pressure is very light — far less than I'd have expected."

"Keep going down, then," said Jag.

The probe continued to descend. Rhombus's web flashed in consternation.

"The pressure sensor must have been damaged — maybe an impact with a piece of gravel. I'm still reading almost no atmospheric pressure."

Jag lifted his upper shoulders. "All right. Fill a compartment here, then bring it all home." The third hatch did not obscure the camera at all, although its opening probably shook the craft enough that had they been able to see anything the view would have jiggled a bit.

"The internal-pressure gauge inside the sample compartment shows the same almost-zero pressure the external gauge is indicating," said Rhombus. "Of course, they run through the same microprocessor.

Anyway, the compartment should have filled instantly, given that it was a vacuum before the hatch opened."

Rhombus left the hatch open for a few more seconds, just to be sure, then closed it, and turned the probe around, bringing it back to Starplex.

Once the probe was back in its launching tube, its sample compartments were disengaged and moved by robot arms onto conveyors, which took them down to Jag's lab. Jag, meanwhile, took an elevator there himself.

The containers plugged into jacks on the walls of the lab.

They didn't have to be opened; sensors and cameras could look inside through the jacks.

Jag sat down in his chair — a real handcrafted Waldahud seat, not a polychair — and activated the tall, thin monitors in front of him. He then keyed in a sequence of commands that selected a standard barrage of tests, and watched with growing amazement as the results appeared on his screens.

Spectroscopy: negative findings.

Electromagnetic sweep: negative findings.

Beta decay: none.

Gamma-ray emissions: none.

Screen after screen lit up: negative findings; none; negative findings; none.

He tapped a key, and the scale beneath the testing bay read off the mass of the sample container: 12.782 kilograms.

"Central Computer," called Jag into the air. "Check the spec sheet for this sample container. How much does it mass when empty?"

"The container's mass is 12.782 kilograms," barked PHANTOM in Waldahudar.

Jag swore. "The fardint thing is empty."

"Correct," said PHANTOM.

Jag tapped a key, and a hologram of Rhombus appeared.

"Teklarg," said Jag, calling the Ib by his name in Waldahu-dar, "that probe you sent out was defective. All of the sample material from its number-two container leaked out on the way back." "Sincere apologies, good Jag," said Rhombus. "I submit to punishment for wasting your time, and will dispatch a replacement at once."

"Do so," said Jag, and he stabbed the button that cut off communications. He turned his attention to the number-one sample container… and was shocked to discover that it, too, had leaked out its contents on the way back. "Shoddy human engineering," he grumbled to himself.

But he was grumbling even more once the second probe's sample containers had been conveyed to his lab. The readings were the same — including the anomalously low air-pressure readings after it had dived into the large sphere.

Once again, Jag summoned up a hologram of Rhombus.

"I say with all peaceful good wishes, dear Jag, that there does not appear to be anything wrong with either probe. The container seals are perfect. Nothing should have been able to leak out."

"Regardless, whatever samples we are collecting are getting out," said Jag. "Which means… well, which means that whatever the samples are made of must be unusual stuff indeed."

Lights moved up Rhombus's web. "A fair assumption."

Jag slid his dental plates together. "There must be a way to bring some of that material aboard for study."

"Doubtless you have already thought of this," said Rhombus, "and I waste both our time by mentioning the idea, but we could use a force box. You know, like the kind they use in labs for handling antimatter."

Jag lifted his upper shoulders. "Acceptable. But don't use an EM forcefield; instead, use artificial-gravity fields to hold the contents away from the box's walls, regardless of what acceleration we use."

"Will do, with obeisance," said Rhombus.

The force box was manipulated by tractor beams. It consisted of eight antigrav generators arranged as the corners of a perfect cube, with wide, paddlelike handles sticking off each face's midpoint to give the tractors something to hold on to. The box was pushed into one of the large gray spheres, and opened there. A second box was manipulated into the swarm of gravel between two of the spheres and activated there. The two boxes were then quickly hauled back in to Starplex.

Finally, the sample containers were maneuvered into separate isolation chambers in Jag's lab. The antigrav trick had been a success: one box did indeed contain samples of the gas that constituted the sphere, and the other held several pieces of translucent gravel plus one partially transparent rock the size of a hen's egg. Now, at last, Jag would find out what they were dealing with.