'I don't see why we should be obligated to people who tried to kill us without reason.'

'I don't know that they had no reason,' Gribardsun said. He turned his large gray eyes on Silverstein, who flushed and chewed savagely on the piece of bison meat he had just put in his mouth.

'I feel I owe some obligations,' Gribardsun said. 'But I'm not neurotic about it. There are limits to what I owe.'

'Are you talking about them or about me?'

'Both.'

A little while later he stretched out on a pile of bison hides and apparently went to sleep almost at once. He did not cover himself with furs, as the natives did, since his thermicron suit kept him warm enough. In fact, he had to open some vents in it against getting too warm. The many bodies in the tent built up the temperature.

Silverstein opened his own suit at many places and took refuge beneath three wolf-skin blankets. But he had trouble getting to sleep. The stench of smoke and unwashed bodies and rotting teeth and chamber pots and the loud snoring of the chief and his old mother and a bite now and then from a louse kept him awake for hours. He had no sooner fallen asleep, or so it seemed to him, than a noise awakened him. He sat up and saw Gribardsun pushing the teenager blonde from him. Evidently she had just come over to him. But Gribardsun was having none of her.

In the morning, Drummond commented on the incident. Gribardsun said, 'I have no moral objection to temporary matings, and I may even have offended her deeply. She probably Wanted to have a child by me because I am a powerful magician and warrior, according to her lights. But I would feel an additional obligation if she had a child by me. I'm not ready for any such thing - yet.'

'You mean you may be ready some day?' Drummond queried. 'How could that be?'

'You'll know if it happens.'

They did not talk much during the rest of the day except on matters of business. Silverstein filmed the day's hunting, which consisted of finding a herd of bison penned inside deep walls of snow. Gribardsun shot one bull to remind the tribesmen of the power of his rifle. Then he used spears to kill several more bulls. After that, he called a halt to the slaughter. By signs he told them they shouldn't waste the meat by killing the whole herd. They wouldn't be able to haul all the meat home today, and if they left carca.s.ses behind, the wolves would get them. The bison were trapped in the 'yard' and most of them would probably starve as soon as they had dug down through the snow and eaten all the gra.s.s under it. This was a common event; the heavy snows often trapped the herbivores.

The next day, Silverstein asked for, and got permission, to return to home camp. He hesitated for a few seconds before saying, 'I don't like to go unarmed.'

Gribardsun took the revolver and a box of ammunition from his pack. 'Use them with good sense,' he said.

Drummond flushed and said, 'Somehow, I have to clear myself. But I seem to get in deeper all the time. Yet I swear I'm innocent!'

'You haven't been proved guilty yet,' Gribardsun said. 'So you are presumed innocent until then. But that doesn't mean you're not on trial. The verdict depends on what you do in the future.'

'This is the d.a.m.nedest situation!' Drummond said, striking his thigh with his fist. 'Whoever would have thought, when we got into the machine to go to 12,000 B.C., that I would be suspected of trying to murder you? Or that Rachel and I would be estranged, perhaps beyond any chance of reconciliation? This is supposed to be a scientific expedition, but if things continue as they have, we're going to fail! We'll return - if we return - with relatively little to show. And that would be a disaster! If this expedition doesn't pay off, there may never be another. Time travel costs too much!'

'Then I suggest that you curb your emotions and work harder,' Gribardsun said. 'Now, I prescribe a tranquilizer for you, but not while you're on the way home. You'll need to be as alert as possible.

Drummond agreed to take the pill when he got back to home camp. He also promised to radio the camp every five minutes so his progress could be checked. And he set out across the deep snow.

Silverstein did not get to the Wota'shaimg camp until late that afternoon. Gribardsun received from von Billmann the report that Silverstein had been sighted. Ten minutes later, von Billmann, very excited, called in. Silverstein had pulled his revolver as he walked up to Rachel and had shot at her. She had dropped to the ground, and so the bullet missed her. Drummond fired three times as she rolled away but missed each time. By then von Billmann had loosed six rounds from his rifle. One bullet struck Drummond in the left shoulder, spun him around and tore off much of the flesh and part of the bone of the shoulder.

Von Billmann had had a concentrated course in first aid and preventive medicine since he was to take over as doctor if anything happened to Gribardsun. He had slapped pseudo-protein over the wound and then given Drummond ma.s.sive doses of P-blood from the stores brought from the vessel. Every person in the tribe had been blood-typed, and Gribardsun had convinced them that they could be donors and n.o.body would establish an evil control over them through their blood. (95 % of the tribe was A with 40% Rh negative.)

By the time Gribardsun arrived, late that evening, Drummond seemed to be out of physical danger. But it was evident next morning that he was suffering from more than physical shock. He did not recognize anybody; he seemed to have gone back to the age of twelve. He was a youth on the third level of Budapest, and his mother was dying. He spoke much in Mandarin Chinese, which his mother had taught him. She was half Chinese and had been born in Lin Shiang and lived there thirteen years before her family went to Budapest in one of those ma.s.sive interchanges of population which took place during the early part of the twenty-first century and still occurred to a lesser extent.

'Here's another obligation for you,' Rachel said as she led him into the conical hut.

All Gribardsun could do at that time was to examine him and commend Robert von Billmann for his medical ability.

Since Drummond could not be moved yet, Gribardsun returned in two days to the other tribe, the Shluwg, as they called themselves. He supervised the care of Drummond through the transceiver at various times of the day. The rest of the time, he studied the Shluwg language and also worked out a means of communicating by signs. He succeeded in putting across his intentions and then, leaving them to think things over, he went back to the Wota'shaimg camp. There he performed several operations on Drummond; he replaced the destroyed bone with plastic so that the shoulder would be almost as good as new. When they returned to their time, the plastic could be replaced with bone.

Drummond was sitting up and walking by then. But he was still withdrawn.

The day came when the Shluwg tribe marched into the area next to the Wota'shaimg camp. The Bear People were prepared for this and so, though they were not friendly, they were not hostile either. They did not approve of Gribardsun's idea of amalgamation of the two groups. But they would do as he suggested and try to get along with the strangers.

To do this it was necessary to set up channels for communication and certain rules of behavior. Several people from each tribe were set to the task of learning the language of the other. Gribardsun led hunters from both tribes on a great three-day hunt which brought in an immense amount of meat. He distributed the meat equally and then, after it was prepared, organized a three-day feast. There were only a few fights, - which he managed to cut short by threatening to punish both sides severely, regardless of where the fault lay.

Seven.

One fine sunny day, the two tribes set off for the trek southward. In three weeks, they had reached Gibraltar. The great rock was larger than in the twenty-first century. Gribardsun halted the tribes long enough to establish contact with several related tribes which lived on or about the rock. Specimens of their language and body tissues were taken along with photographs. Meat was exchanged for their tools and weapons and their necklaces of sea sh.e.l.ls.

The blood taken from the Gibraltar tribes was heavily B and slightly A, with four individuals who were O. This presented a puzzling picture. The answer, if it would ever be found, would probably come after all data was brought back to the twenty-first century.

The two tribes marched on across the land bridge which, at that time, was over six miles wide. They entered North Africa and continued along the coast eastward. The coast was about four to five hundred feet below the level of the Mediterranean as the twenty-first century knew it. The group moved slowly, because the three scientists were busy taking specimens and measurements. As the scientific collection increased, more people had to be detailed to carry the growing bulk of information. And that meant that the work of the bearers had to be parceled out among the others. As a result, Gribardsun had to spend more time hunting with the rifle to feed the mob. But he also had to devote extra time to the scientific work, since Silverstein was incapable of performing his duties.

The total range of duties kept Gribardsun working from dawn or before until far past supper. But he was an excellent administrator, in that he knew the value of letting his inferiors share the burden.

'I learned that in His Majesty's Service,' he told Rachel.

'His? But...

'I meant Her Majesty's, of course.'

'Even so,' Rachel said, 'that would make you born...'

It was just a matter of speaking,' he said. 'One of the archaic phrases of which I'm so fond. I meant, in the government service, of course. But I learned that if you don't want to kill yourself with work and worry, you delegate responsibility.'

'You should be exhausted,' she said. 'But you took fresh as ever. I'm the one who's dying of overwork and lack of sleep, and yet my duties are as nothing compared to yours.'

'You're worried about Drummond.'

'Yes. It's all over between us. And he may even have tried to - well, he did try to kill me, and I believe he tried to kill you. But he was mentally ill. He couldn't help himself. I don't hate him. I just don't love him any more. Yet, I feel responsible for him. Sorry for him, I suppose. I can understand him. I sometimes feel that I'm going insane myself. I just can't get a strong grip on reality. If this is reality. It all seems so dreamlike and too often nightmarish. Sometimes I think I'll scream if I don't see something familiar. I know it's blasphemy, from a scientific viewpoint, but I wish that we could return to our time tomorrow. I'd chuck all that has to be learned for a chance to climb aboard and know that in a few minutes I'd be back in the twenty-first century.'

'This reaction - this temporal shock - is just as valuable a datum as anything we'll bring back,' he said. 'I hope it won't cause time travel to be abandoned. I doubt it, since only one of us is very much incapacitated, and we can't prove that that happened because of temporal dislocation. In any event, you can be sure that those chosen for future expeditions will be much more deeply tested. But,' he added, smiling, 'it will be too late for anybody on this expedition.'

'Why do you smile?'

'I'll tell you some day.'

The two tribes moved on along the coast of Morocco. Though it was cold, often below freezing, and snow fell, the climate was not as rigorous as in Iberia. They marched more swiftly, but their halts were longer, since the three scientists had enough to do to keep them in each area for six months. They took thousands of photographs, made maps of the coastal areas, took samples of the soil and the water and specimens of flora and fauna, from local bacteria and amoeba and earthworms up to the elephants. They could not take the elephant bodies with them, of course, but Gribardsun and Rachel Silverstein did random dissections and preserved tissue slides. They made Carbon-14 and xenonargon datings on the spot with their equipment. They fished and then studied specimens before giving them over to the cooks.

The tribes living on the coast were generally small and lived by hunting and fishing. Rivers ran through the Sahara and emptied into the western half of the Mediterranean. The river mouths were plentiful with fish and seal and porpoise, and inland were the elephants and rhinoceroses, antelope and deer and goat, horses, aurochs, and even bison. There were also lions and bears and leopards. Although the great snow leopards existed in France and Iberia, Gribardsun had never seen one in those regions. But he had not been in Africa more than a week before he glimpsed three at a distance.

The natives were larger than the Arab-Berber type of the modern era but somewhat smaller, thinner-boned and darker than the modern Europeans. They were also longer-headed and tended toward aquiline faces. So far, no Negroes had been encountered nor had any of the Africans ever heard of black men.

'It's too late, even in 12,000 B.C., to determine the origin of the Negro race,' Gribardsun said. 'I don't suppose we'll ever know if it's true that they arose somewhere in southern Asia and then migrated to Africa and Austronesia and were killed off or absorbed on the Asiatic mainland. Or if they originated in Africa and then, somehow, some migrated to New Guinea and Melanesia, leaving d.a.m.n few traces along the trail. Even so, we might learn something if we could explore East Africa now and learn what types are living there. I suspect there'd be some Caucasoid and Capsoid types and perhaps some Negritos.'

'You surely aren't thinking of taking us down there?' Rachel said.

'I would object,' von Billmann said. 'That would take us entirely too far from the vessel; it would definitely imperil the expedition. Moreover, if we're going to roam far and wide, we should be doing it in central Europe, preferably somewhere between the Elbe and Vistula. We should be ascertaining whether proto-Indo-Hitt.i.te speech exists there, or ...'