I

The Planetarium Club abounds in unexpected conversations. It has a core of scientific men who are mostly devotees of the exact sciences, grave, shy, precise men, but wrapped round them are layers of biologists, engineers, explorers, civil servants, patent lawyers, criminologists, writers, even an artist or so. Almost any subject may be started in the smoking–room where most of the talk goes on, but the feeling against chewed newspaper is strong. Mr. Davis, as he ascended the club steps, made an effort to throw off those vague shadows that oppressed his mind, and to brighten his bearing to the quality that may be reasonably expected of a temperamental optimist.

But as he recrossed the hall from the vestiary to the dining–room he was still undecided whether he should sit at one of the small tables and go on with his state of uneasy deterioration, or take a place at one of the sociable boards. He elected for solitude, but repented as soon as his decision was made, and after his solitary lunch he made a real effort at sociability and joined a talking circle of a dozen men or more between the window and the fire, sitting down next to Foxfield, that hairy, untidy biologist, for whom he had a slightly condescending liking. The talk was rather under the stress of a new member, a parliamentary barrister, who might be almost anything in a few years' time and manifestly felt as much. This man had been elected before it was realized that he was slightly larger than any one else in the club and disposed to behave accordingly, and his conversational method was rather an elucidatory cross–examination than an original contribution to the interchanges.

'Tell me,' he would say and even point a finger. 'I don't know anything about these things. Tell me—'

'Tell me,' except in the case of monarchs, heirs apparent, and presidents of the United States, is by the standards of the Planetarium atrocious conversational manners. But so far no one in the club had been able to get this point of view over to the new–comer. It would happen sooner or later but so far it had not happened. He was talking now with an air of making out some sort of case against modern physics and demonstrating how entirely more sensible and practical a mind which had passed through the ennobling exercises of Greats and a straightforward legal and political training could be.

'Atoms and force were good enough for Lucretius and they were good enough for my stinks master when I was a boy. Then suddenly you have to disturb all that. There's wonderful discoveries, and the air is full of electrons and neutrons and positons.'

'Positrons,' a voice corrected.

'It's all the same to us. Positrons. And photons and protons and deutrons. Alpha rays and Beta rays and Gamma rays and X rays and Y rays. And they fly about like solar systems and all the rest of it. And the dear old Universe that used to be fixed and stable begins to expand and contract—like God playing a concertina. Tell me—frankly. I suggest to you—it's a bluff. It's something out of nothing. It's just a way of selling us mystery bottles with scientific labels. I ask you.'

He paused with the air of a man who has put a poser.

A small, elderly, but still acutely acid old gentleman was sitting deep in one of the armchairs. The finger had not challenged him, but now he put out a lean hand and spoke with a thin penetrating voice, like a rapier, with the faint glint of a Scotch accent along the edge.

'You say Tell me—and Tell me. Will you have the grace to listen while I tell ye? And not interrupt?'

And when the slightly outsize member made as if he had something further to say, the old gentleman just raised his hand and said: 'No. Listen, I tell ye, and told you shall be.'

The rising man, just faintly abashed, assumed an attitude of sceptical and slightly impatient intelligence, looking round the group for support in what he evidently imagined was going to be a duel of wits. Just for a moment he imagined that. And then suddenly he felt like facing twelve implacably hostile jurymen and the first lesson of the Planetarium Club entered into his soul. Not to bounce.

Quietly and unobtrusively he allowed himself to lapse into the pose of the modest best boy in the class who knows that he still has much to learn and who cannot command any one to tell him but is glad to be told.

'These things boil down,' said the old gentleman. 'I've lectured about them for years. And followed the changes. When one gets old one has to be concise and it's fortunate I've had some practice in packing my statements. Still I'll have to take five minutes. I'll do all I can for you. Those Oxford teachers of yours—for it's Oxford you come from—probably left your mathematical philosophy in a worst state than they found it when you came up from your English public school—if indeed your formula–dodging schoolmasters gave you any mathematical understanding at all even there—so I may not be able to explain everything to you. Some bits I'll just have to tell you—as you put it. But it's really quite simple and credible stuff they've made of it in the last twenty–five years, Rutherford and Bragg and Niels Bohr and the rest of those fellows, and the younger people find no difficulty about it at all.'

And with that and a galling air of careful simplification he proceeded to unfold a compact modern view of space and time and the movements of things therein. 'Don't ask me what electricity is,' he said, 'and I'll tell you everything else as we have it up to date. It's none so complicated as you think and there's never a contradiction.'

And very neatly he took his nucleus, twisted up his atoms with electrons and neutrons round the central proton, and sent them eddying into a world of throbbing photons. Then he ran his hand along the sixty–odd octaves of the spectrum from the hundred–yard electro–magnetic undulations beyond the longest radio length through heat rays and light rays to X rays and Gamma rays, smacked a few atoms together, shot them through with helium atoms, and described the results, and by way of epilogue gave a lucid word to those flying sub–atomies, the cosmic rays.

'After all, it's none so confused,' he said, and indeed the pictures that arose as one listened to his slightly remonstrating, very persuasive Scotch intonation had the music of ripples and wavelets, of dancing reflections upon the side of a ship, of the concentric colour rings of films on water, of every sort of pleasant patterning and logical ornamentation. He made dead matter dance and circle, set to partners, interfere, shimmer, glow, become iridescent and mysteriously endowed with energy. The atoms of our fathers seemed by contrast like a game of marbles abandoned in a corner of a muddy playground on a wet day. He even had a cautious word for the young neutrinos, the latest aspirants to his dance in the atomic assembly–rooms. The one or two men who were experts in the subject listened, pleased to hear the A B C of their subject so lucidly delivered, and the rest were glad to check up their vague impressions of these fluctuating modern conceptions.

'And where do we come in?' asked someone. 'Where is thought and the soul in all this?'

'Just a film, just a thin zone of reflection halfway in the scale of size between those electrons and the stars.'