“It was understood,” said one of the Melfans so quietly that it was plain that the remark was not intended to be overheard, “the first time you explained it.”
Gurronsevas decided to be diplomatically deaf.
Murchison had not spoken directly to Gurronsevas since its arrival; and since Timmins had been eagerly passing on all of the necessary information, there was no reason other than mere politeness for him to speak to the pathologist. He was beginning to have serious doubts about the feasibility of the whole project, and to say less now would reduce any subsequent embarrassment caused by an apology for wasting the other’s time. In any case, the pathologist was lying flat on the raft with its face and both eyes directed at the launch preparations.
Gurronsevas noted with growing impatience that most of Timmins’ attention was being directed at Pathologist Murchison. He reminded himself that the Earth-human DBDG classification belonged to a species which (unlike the vast majority of other life-forms within the Federation, who were intensely active only for short periods in the year) was capable of sexual arousal and activity throughout its adult life. There were some who envied them this ability, but privately Gurronsevas considered it a disadvantage which all too often reduced the quality of their mentation. But again, this was a good time to maintain diplomatic silence.
The next test began well, with the thin, bubbling jet of compressed gas driving the vehicle forward in a not quite straight line at a slowly increasing velocity and constant depth. The Chalder’s prey was amphibious so that it was normal for it to release air while fleeing. When the first lateral thrust came with its smaller and briefer explosion of bubbles, the vehicle made a wide curve that was bringing it back towards the raft. Another gas capsule melted and burst on the same side and the circle tightened until suddenly the vehicle broke the surface and began spinning and skidding uncontrollably over the water as the propulsion unit reinforced the spin set up by the two lateral jets. The others burst at random without effect and a moment later the vehicle came to rest, still spinning slowly, with its topside breaking the surface.
One of the Melfans retrieved it and a technical argument started regarding the inherent instability of the flattened ovoid configuration. Gurronsevas was too angry and disappointed to join in, but not so Murchison.
“This is not my specialty,” said the pathologist, “but when I used to play with my big brother’s toy boats as a child, they were fitted with keels which gave them directional stability even when the wind changed. When we grew older and progressed to speedboats and submarines we had radio-controlled rudders and diving vanes to maintain or change direction or depth. Couldn’t something similar be used here?”
Timmins and the Melfans stopped talking but did not reply. They were all looking at Gurronsevas. Plainly he could remain silent no longer.
“No,” he said. “Not unless the radio receiver and actuating devices could be fabricated from materials that were non-metallic, non-toxic and edible.”
“Edible?” said Murchison. In a quieter voice it went on, “So that’s why I was sent here. Until now I didn’t know that Thorny had a sense of humor. Please go on.”
“In its final form,” said Gurronsevas, doing so, “the entire vehicle would have to be edible, or at least non-toxic to the Chalder life-form, and that would include the water-soluble gas containers for propulsion and steering. The problem with the addition of a keel, which would also have to be edible and not sharp-edged enough to risk injury to the patient’s mouth, is that the structure would change the visual appearance of the vehicle so that it no longer resembled the Chalders’ natural and greatly preferred food source, which is a streamlined, hard-shelled, aquatic animal of the size and configuration of our test object. A weak and convalescent Chalder patient might not consider it worth the effort to chase unfamiliar food.
“You will understand,” Gurronsevas continued, “that the confined space of the AUGL ward causes physical as well as physiological effects which unnecessarily lengthen the period of convalescence. The patients become lazy, listless, almost debilitated by their inability to exercise properly. I should explain that the physiology of the AUGLs is such that—”
“I am familiar with the physiology of the Chalders, among others,” said Murchison.
For a moment Gurronsevas radiated embarrassment so strongly that he was surprised the water around him did not steam. He said, “My apologies, Pathologist Murchison. This Chalder knowledge is very new to me, and very exciting, and in my excitement I stupidly assumed a similar level of ignorance in others. I had no wish to offend you.”
“You didn’t,” said the pathologist. “I was just trying to stop your wasting time on an unnecessary explanation. But I have no knowledge or professional interest in the non-intelligent life-forms on Chalderescol, including the food animal you are trying to copy. How does the real one propel itself and take evasive action and manage to retain directional stability?”
Feeling greatly relieved, Gurronsevas said quickly, “On each side the animal has a set of eight laterally-mounted paddles. Their frequency of beat and angle of attack against the water can be varied so as to make the animal rise, dive, or — by going into reverse beat on one side — make a sudden change in direction. The paddle structure is a translucent framework supporting a transparent membrane which, when the creature is fleeing, is beating so fast as to be virtually invisible. When there is a change in direction, minor turbulence is created which is visually similar to the bubbles produced by the test object’s attitude jets.
“Regrettably,” he added, “the model looks but does not behave like the real thing. It is hopelessly unstable.”
“That it is,” said Murchison. For several minutes it remained silent, staring thoughtfully at the test object in the water while Timmins stared just as intently at the pathologist and the two Melfan technicians talked quietly to each other. Suddenly it spoke.
“We need a keel of some kind,” it said in a quiet but excited voice, “but one which will not alter the object’s appearance. The original life-form uses paddles which are translucent and move too quickly to be seen. Why don’t we use an invisible keel?”
Without giving anyone a chance to reply it went on, “We should be able to make it from a shaped and hardened transparent gel possessing the same refractive index as water. It would have to be edible, naturally, and be weak enough structurally not to damage the patient’s teeth or digestive tract. Some of the constituents I have in mind — well, the taste would range from neutral to downright awful, but we can work on that until—”
“You can produce this edible stabilizer?” Gurronsevas broke in, incredulity making him forget good manners. “Your department has done so before?”
“No,” said Murchison. “We have never been asked to do so before. It will be a difficult but not impossible biochemical problem to devise an edible and Chalder-non-toxic material of the required consistency. The shaping of the material into a keel and its attachment to the vehicle will be covered by your food synthesizer programming.”
“Meanwhile,” Timmins joined in, “we can start fitting non-edible and visible keels to the test vehicle to see which size and shape works best. Kledath, Dremon, lift it onto the raft. We’ve got work to do.”
Murchison rolled off the raft so as to give the others more space to work. It lay floating on its back beside Gurronsevas, completely relaxed, with eyes closed and only its face above the surface.
“I think you have solved this problem, Pathologist Murchison,” he said, “and I am most grateful.”
“We aim to please,” the pathologist said. Its mouth opened slightly in a smile and the eyes remained closed. “Have you other problems?”