Mansard had been, but it must have been very close. She knew that Dr. Mansard had invented the surgiscope.

This was an instrument with a three-dimensional screen as its heart. The screen was a cubical frame in which an apparently solid image was built up of an object under an electron microscope.

The actual cutting instrument of the surgiscope was an ion stream. By operating a tool in the three-dimensional screen, corresponding movements were made by the ion stream on the object under the microscope. The principle was the same as that used in operation of remote control “hands” in atomic laboratories to handle hot material, and with the surgiscope very delicate operations could be performed at the cellular level.

Dr. Mansard and his wife had disappeared into the turbulent atmosphere of Jupiter just after his invention of the surgiscope, and it had been developed by Dom Blessing. Its success had built Spaceway Instruments, Incorporated, which Blessing headed.

Through all these years since Dr. Mansard's disappearance, Blessing had been searching the Jovian moons for a second, hidden laboratory of Dr. Mansard. When it was found at last, he sent Trella, his most trusted secretary, to Ganymede to bring back to him the notebooks found there.

Blessing would, of course, be happy to learn that a son of Dr. Mansard lived, and would see that he received his rightful share of the inheritance. Because of this, Trella was tempted to tell Quest the good news herself; but she decided against it. It was Blessing's privilege to do this his own way, and he might not appreciate her meddling.

At midtrip, Trella made a rueful confession to Jakdane.

“It seems I was taking unnecessary precautions when I asked you to be a chaperon,” she said. “I kept waiting for Quest to do something, and when he didn't I told him I loved him.”

“What did he say?”

“It's very peculiar,” she said unhappily. “He said he can't love me. He said he wants to love me and he feels that he should, but there's something in him that refuses to permit it.”

She expected Jakdane to salve her wounded feelings with a sympathetic pleasantry, but he did not. Instead, he just looked at her very thoughtfully and said no more about the matter.

He explained his attitude after Asrange ran amuck.

Asrange was the third passenger. He was a lean, saturnine individual who said little and kept to himself as much as possible. He was distantly polite in his relations with both crew and other passengers, and never showed the slightest spark of emotion … until the day Quest squirted coffee on him.

It was one of those accidents that can occur easily in space. The passengers and the two crewmen on that particular waking shift (including Jakdane) were eating lunch on the center-deck. Quest picked up his bulb of coffee, but inadvertently pressed it before he got it to his lips. The coffee squirted all over the front of Asrange's clean white tunic.

“I'm sorry!” exclaimed Quest in distress.

The man's eyes went wide and he snarled. So quickly it seemed impossible, he had unbuckled himself from his seat and hurled himself backward from the table with an incoherent cry. He seized the first object his hand touched—it happened to be a heavy wooden cane leaning against Jakdane's bunk—propelled himself like a projectile at Quest.

Quest rose from the table in a sudden uncoiling of movement. He did not unbuckle his safety belt—he rose and it snapped like a string.

For a moment Trella thought he was going to meet Asrange's assault. But he fled in a long leap toward the companionway leading to the astrogation deck above. Landing feet-first in the middle of the table and rebounding, Asrange pursued with the stick upraised.

In his haste, Quest missed the companionway in his leap and was cornered