But the point was lost on Kingsley. He went on: 'Any attempt to use sound would be drowned by the enormous amount of background noise that must exist inside the Cloud. It would be far worse than trying to talk in a roaring gale. I think we can be pretty sure that communication would have to take place electrically.'

'That seems fair enough.'

'Good. Well, the next point is that by our standards the distances between the individuals would be very large, since the Cloud by our standards is enormously large. It would obviously be intolerable to rely on essentially D.C. methods over such distances.'

'D.C. methods? Chris, will you please try to avoid jargon?'

'Direct current.'

'That explains it, I suppose!'

'Oh, the sort of thing we get on the telephone. Roughly speaking, the difference between D.C. communication and A.C. communication is the difference between the telephone and radio.'

Marlowe grinned at Ann Halsey.

'What Chris is trying to say in his inimitable manner is that communication must occur by radiative propagation.'

'If you think that makes it clearer ...'

'Of course it's clear. Stop being obstructive, Ann. Radiative propagation occurs when we emit a light signal or a radio signal. It travels across s.p.a.ce through a vacuum at a speed of 186,000 miles per second. Even at this speed it would still take about ten minutes for a signal to travel across the Cloud.

'My next point is that the volume of information that can be transmitted radiatively is enormously greater than the amount that we can communicate by ordinary sound. We've seen that with our pulsed radio transmitters. So if this Cloud contains separate individuals, the individuals must be able to communicate on a vastly more detailed scale than we can. What we can get across in an hour of talk they might get across in a hundredth of a second.'

'Ah, I begin to see light,' broke in McNeil. 'If communication occurs on such a scale then it becomes somewhat doubtful whether we should talk any more of separate individuals!'

'You're home, John!'

'But I I'm not home,' said Parkinson. not home,' said Parkinson.

'In vulgar parlance,' said McNeil amiably, 'what Chris is saying is that individuals in the Cloud, if there are any, must be highly telepathic, so telepathic that it becomes rather meaningless to regard them as being really separate from each other.'

'Then why didn't he say so in the first place?' from Ann Halsey.

'Because like most vulgar parlance, the word "telepathy" doesn't really mean very much.'

'Well, it certainly means a great deal more to me.'

'And what does it mean to you, Ann?'

'It means conveying one's thoughts without talking, or of course without writing or winking or anything like that.'

'In other words it means if it means anything at all communication by a non-acoustic medium.'

'And that means using radiative propagation,' chipped in Leicester.

'And radiative propagation means the use of alternating currents, not the direct currents and voltages we use in our brains.'

'But I thought we were capable of some degree of telepathy,' suggested Parkinson.

'Rubbish. Our brains simply don't work the right way for telepathy. Everything is based on D.C. voltages, and radiative transmission is impossible that way.'

'I know this is rather a red herring, but I thought these extra-sensory people had established some rather remarkable correlations,' Parkinson persisted.

'b.l.o.o.d.y bad science,' growled Alexandrov. 'Correlations obtained after experiments done is b.l.o.o.d.y bad. Only prediction in science.'

'I don't follow.'

'What Alexis means is that only predictions really count in science,' explained Weichart. 'That's the way Kingsley downed me an hour or two ago. It's no good doing a lot of experiments first and then discovering a lot of correlations afterwards, not unless the correlations can be used for making new predictions. Otherwise it's like betting on a race after it's been run.'

'Kingsley's ideas have many very interesting neurological implications,' McNeil remarked. 'Communication for us is a matter of extreme difficulty. We ourselves have to make a translation of the electrical activity essentially D.C. activity in our brains. To do this, quite a bit of the brain is given over to the control of the lip muscles and of the vocal chords. Even so our translation is very incomplete. We don't do too badly perhaps in conveying simple ideas, but the conveying of emotions is very difficult. Kingsley's little beasts could, I suppose, convey emotions too, and that's another reason why it's rather meaningless to talk of separate individuals. It's rather terrifying to realize that everything we've been talking about tonight and conveying so inadequately from one to another could be communicated with vastly greater precision and understanding among Kingsley's little beasts in about a hundredth of a second.'

'I'd like to follow the idea of separate individuals a little further,' said Barnett, turning to Kingsley. 'Would you think of each individual in the Cloud as building a radiative transmitter of some sort?'

'Not as building building a transmitter. Let me describe how I see biological evolution taking place within the Cloud. At an early stage I think there would be a whole lot of more or less separate disconnected individuals. Then communication would develop, not by a deliberate inorganic building of a means of radiative transmission, but through a slow biological development. The individuals would develop a means of radiative transmission as a biological organ, rather as we have developed a mouth, tongue, lips, and vocal chords. Communication would improve to a degree that we can scarcely contemplate. A thought would no sooner be thought than it would be communicated. An emotion would no sooner be experienced than it would be shared. With this would come a submergence of the individual and an evolution into a coherent whole. The beast, as I visualize it, need not be located in a particular place in the Cloud. Its different parts may be spread through the Cloud, but I regard it as a neurological unity, interlocked by a communication system in which signals are transmitted back and forth at a speed of 186,000 miles a second.' a transmitter. Let me describe how I see biological evolution taking place within the Cloud. At an early stage I think there would be a whole lot of more or less separate disconnected individuals. Then communication would develop, not by a deliberate inorganic building of a means of radiative transmission, but through a slow biological development. The individuals would develop a means of radiative transmission as a biological organ, rather as we have developed a mouth, tongue, lips, and vocal chords. Communication would improve to a degree that we can scarcely contemplate. A thought would no sooner be thought than it would be communicated. An emotion would no sooner be experienced than it would be shared. With this would come a submergence of the individual and an evolution into a coherent whole. The beast, as I visualize it, need not be located in a particular place in the Cloud. Its different parts may be spread through the Cloud, but I regard it as a neurological unity, interlocked by a communication system in which signals are transmitted back and forth at a speed of 186,000 miles a second.'

'We ought to get down to considering those signals more closely. I suppose they'd have to have a longish wave-length. Ordinary light presumably would be useless since the Cloud is opaque to it,' said Leicester.

'My guess is that the signals are radio waves,' went on Kingsley. 'There's a good reason why it should be so. To be really efficient one must have complete phase control in a communication system. This can be done with radio waves, but not, so far as we know, with shorter wave-lengths.'

McNeil was excited.

'Our radio transmissions!' he exclaimed. 'They'd have interfered with the beast's neurological control.'

'They would if they'd been allowed to.'

'What d'you mean, Chris?'

'Well, the beast hasn't only to contend with our transmissions, but with the whole welter of cosmic radio waves. From all quarters of the Universe there'd be radio waves interfering with its neurological activity unless it had developed some form of protection.'

'What sort of protection have you in mind?'

'Electrical discharges in the outer part of the Cloud causing sufficient ionization to prevent the entry of external radio waves. Such a protection would be as essential as the skull is to the human brain.'

Aniseed smoke was rapidly filling the room. Marlowe suddenly found his pipe too hot to hold and put it down gingerly.

'My G.o.d, you think this explains the rise of ionization in the atmosphere, when we switch on our transmitters?'

'That's the general idea. We were talking earlier on about a feedback mechanism. That, I imagine, is just what the beast has got. If any external waves get in too deeply, then up go the voltages and away go the discharges until the waves can get in no farther.'

'But the ionization takes place in our own atmosphere.'

'For this purpose I think we can regard our atmosphere as a part of the Cloud. We know from the shimmering of the night sky that gas extends all the way from the Earth to the denser parts of the Cloud, the disk-like parts. In short we're inside the Cloud, electronically speaking. That, I think, explains our communication troubles. At an earlier stage, when we were outside the Cloud, the beast didn't protect itself by ionizing our atmosphere, but through its outer electronic shield. But once we got inside the shield the discharges began to occur in our own atmosphere. The beast has been boxing-in our transmissions.'

'Very fine reasoning, Chris,' said Marlowe.

'h.e.l.lish fine,' nodded Alexandrov.

'How about the one-centimetre transmissions? They went through all right,' Weichart objected.

'Although the chain of reasoning is getting rather long there's a suggestion that one can make on that. I think it's worth making because it suggests the next action we might take. It seems to me most unlikely that this Cloud is unique. Nature doesn't work in unique examples. So let's suppose there are lots of these beasts inhabiting the Galaxy. Then I would expect communication to occur between one cloud and another. This would imply that some wave-lengths would be required for external communication purposes, wave-lengths that could penetrate into the Cloud and would do no neurological harm.'

'And you think one centimetre may be such a wave-length?'

'That's the general idea.'

'But then why was there no reply to our one-centimetre transmission?' asked Parkinson.

'Perhaps because we sent no message. There'd be no point in replying to a perfectly blank transmission.'

'Then we ought to start sending pulsed messages on the one centimetre,' exclaimed Leicester. 'But how can we expect the Cloud to decipher them?'

'That's not an urgent problem to begin with. It will be obvious that our transmissions contain information that will be clear from the frequent repet.i.tion of various patterns. As soon as the Cloud realizes that our transmissions have intelligent control behind them I think we can expect some sort of reply. How long will it take to get started, Harry? You're not in a position to modulate the one centimetre yet, are you?'

'No, but we can be in a couple of days, if we work night shifts. I had a sort of presentiment that I wasn't going to see my bed tonight. Come on, chaps, let's get started.'

Leicester stood up, stretched himself, and ambled out. The meeting broke up. Kingsley took Parkinson on one side.

'Look, Parkinson,' he said, 'there's no need to go gabbling about this until we know more about it.'

'Of course not. The Prime Minister suspects I'm off my head as it is.'

'There is one thing that you might pa.s.s on, though. If London, Washington, and the rest of the political circus could get ten-centimetre transmitters working, it's just possible that they might avoid the fadeout trouble.'

When Kingsley and Ann Halsey were alone later that night, Ann remarked: 'How on earth did you come on such an idea, Chris?'

'Well, it's pretty obvious really. The trouble is that we're all inhibited against such thinking. The idea that the Earth is the only possible abode of life runs pretty deep in spite of all the science fiction and kids' comics. If we had been able to look at the business with an impartial eye we should have spotted it long ago. Right from the first, things have gone wrong and they've gone wrong according to a systematic sort of pattern. Once I overcame the psychological block, I saw all the difficulties could be removed by one simple and entirely plausible step. One by one the bits of the puzzle fitted into place. I think Alexandrov probably had the same idea, only his English is a bit on the terse side.'

'On the b.l.o.o.d.y terse side, you mean. But seriously, do you think this communication business will work?'

'I very much hope so. It's quite crucial that it should.'

'Why do you say that?'

'Think of the disasters the Earth has suffered so far, without the Cloud taking any purposive steps against us. A bit of reflection from its surface nearly roasted us. A short obscuration of the Sun nearly froze us. If the merest tiny fraction of the energy controlled by the Cloud should be directed against us we should be wiped out, every plant and animal.'

'But why should that happen?'

'How can one tell? Do you think of the tiny beetle or the ant that you crush under your foot on an afternoon's walk? One of those gas bullets that hit the Moon three months ago would finish us. Sooner or later the Cloud will probably let fly with some more of 'em. Or we might be electrocuted in some monstrous discharge.'

'Could the Cloud really do that?'

'Easily. The energy that it controls is simply enormous. If we can get some sort of a message across, then perhaps the Cloud will take the trouble to avoid crushing us under its foot.'

'But why should it bother?'

'Well, if a beetle were to say to you, "Please, Miss Halsey, will you avoid treading here, otherwise I shall be crushed," wouldn't you be willing to move your foot a trifle?'

Communication Established

Four days later after thirty-three hours of transmission from Nortonstowe the first communication from the Cloud came through. It would be idle to attempt to describe the prevailing excitement. Suffice it to say that frenzied attempts were made to decode the incoming message, for message it obviously was, judging from regular patterns that could be discovered among the rapid pulses of radio signal. The attempts were not successful. Nor was this surprising, for, as Kingsley remarked, it can be difficult enough to discover a code when the message has initially been thought out in a known language. Here the language of the Cloud was entirely unknown.

'That seems good sense to me,' remarked Leicester. 'Our problem isn't likely to be any easier than the Cloud's problem, and the Cloud won't understand our messages until it's discovered the English language.'

'The problem's probably a great deal worse than that,' said Kingsley. 'We've every reason to believe that the Cloud is more intelligent than we are, so its language whatever it may be is likely to be a lot more complicated than ours. My proposal is that we stop bothering trying to decipher the messages we've been receiving. Instead I propose we rely on the Cloud being able to decipher our messages. Then when it's learned our language it can reply in our own code.'

'Dam' good idea. Always force foreigner to learn English,' said Alexandrov to Yvette Hedelfort.

'To begin with, I think we should stick as much as possible to science and mathematics because these are likely to be the best common denominator. Later on we can try sociological stuff. The big job will be to record all the material we want to transmit.'

'You mean that we ought to transmit a sort of basic course in science and mathematics, and in basic English?' said Weichart.

'That's the idea. And I think we ought to get down to it right away.'

The policy was successful, too successful. Within two days the first intelligible reply was received. It read: 'Message received. Information slight. Send more.'

For the next week almost everyone was kept busy reading from suitably chosen books. The readings were recorded and then transmitted. But always there came short replies demanding more information, and still more information.

Marlowe said to Kingsley: 'It's no good, Chris, we shall have to think up a new idea. This brute'll soon exhaust the lot of us. My voice is getting as hoa.r.s.e as an old crow with this constant reading.'

'Harry Leicester's working on a new idea.'

'I'm glad of that. What is it?'

'Well, it may kill two birds with one stone. The slowness of our present methods isn't the only trouble. Another difficulty is that a great deal of what we're sending must seem shockingly unintelligible. A whole mult.i.tude of words in our language refer to objects that we see and touch and hear. Unless the Cloud knows what those objects are I don't see how it can make sense of a great deal of the stuff we're churning out. If you haven't ever seen an orange or come in contact with an orange in some way, I don't see how you could possibly know what the word "orange" means, however intelligent you were.'

'I can see that. What d'you propose to do?'

'It was Harry's idea. He thinks he can use a television camera. Luckily I got Parkinson to lay some in. Harry thinks he can hook one up to our transmitter, and what's more he's pretty confident that he can modify it to do something like 20,000 lines instead of the miserable 450 or so lines of ordinary television.'

'That's because of the much lower wave-length?'

'Yes, of course. We ought to be able to transmit an excellent picture.'

'But the Cloud doesn't have a television tube!'

'Of course not. How the Cloud decides to a.n.a.lyse our signals is entirely its own business. What we must make sure of is that we're transmitting all relevant information. So far, we've been doing a pretty poor job and the Cloud's been quite right to complain.'

'How do you propose to use the television camera?'

'We'll start by going through a whole list of words, demonstrating various nouns and verbs. This will be preliminary. It's got to be carefully done but it shouldn't take too long to go through about five thousand words perhaps a week. Then we can transmit the contents of whole books by scanning the pages with the camera. It should be possible to deal with the whole Encyclopaedia Britannica Encyclopaedia Britannica in a few days by this method.' in a few days by this method.'

'That certainly ought to satisfy the brute's thirst for knowledge. Well, I suppose I'd better get back to my reading! Tell me when the camera's going to be ready. I can't estimate how glad I'll be to get rid of this ch.o.r.e.'

Later Kingsley could be seen in contact with Leicester. 'I'm sorry, Harry,' he said, 'but I've got some other problems.'